Developing suitable photocatalysts and understanding their intrinsic catalytic mechanism remain key challenges in the pursuit of highly active,good selective,and long-term stable photocatalytic CO_(2)reduction(PCO_(2)...Developing suitable photocatalysts and understanding their intrinsic catalytic mechanism remain key challenges in the pursuit of highly active,good selective,and long-term stable photocatalytic CO_(2)reduction(PCO_(2)R)systems.Herein,monoclinic Cu_(2)(OH)_(2)CO_(3)is firstly proven to be a new class of photocatalyst,which has excellent catalytic stability and selectivity for PCO_(2)R in the absence of any sacrificial agent and cocatalysts.Based on a Cu_(2)(OH)_(2)^(13)CO_(3)photocatalyst and 13CO_(2)two-sided^(13)C isotopic tracer strategy,and combined with in situ diffused reflectance infrared Fourier transform spectroscopy(DRIFTS)analysis and density functional theory(DFT)calculations,two main CO_(2)transformation routes,and the photo-decomposition and self-restructuring dynamic equilibrium mechanism of Cu_(2)(OH)_(2)CO_(3)are definitely revealed.The PCO_(2)R activity of Cu_(2)(OH)_(2)CO_(3)is comparable to some of state-of-the-art novel photocatalysts.Significantly,the PCO_(2)R properties can be further greatly enhanced by simply combining Cu_(2)(OH)_(2)CO_(3)with typical TiO_(2)to construct composites photocatalyst.The highest CO_(2)and CH_(4)production rates by 7.5 wt%Cu_(2)(OH)_(2)CO_(3)-TiO_(2)reach 16.4μmol g^(-1)h^(-1)and 116.0μmol g^(-1)h^(-1),respectively,which are even higher than that of some of PCO_(2)R systems containing sacrificial agents or precious metals modified photocatalysts.This work provides a better understanding for the PCO_(2)R mechanism at the atomic levels,and also indicates that basic carbonate photocatalysts have broad application potential in the future.展开更多
The global energy-related CO_(2) emissions have rapidly increased as the world economy heavily relied on fossil fuels.This paper explores the pressing challenge of CO_(2) emissions and highlights the role of porous me...The global energy-related CO_(2) emissions have rapidly increased as the world economy heavily relied on fossil fuels.This paper explores the pressing challenge of CO_(2) emissions and highlights the role of porous metal oxide materials in the electrocatalytic reduction of CO_(2)(CO_(2)RR).The focus is on the development of robust and selective catalysts,particularly metal and metal-oxide-based materials.Porous metal oxides offer high surface area,enhancing the accessibility to active sites and improving reaction kinetics.The tunability of these materials allows for tailored catalytic behavior,targeting optimized reaction mechanisms for CO_(2)RR.The work also discusses the various synthesis strategies and identifies key structural and compositional features,addressing challenges like high overpotential,poor selectivity,and low stability.Based on these insights,we suggest avenues for future research on porous metal oxide materials for electrochemical CO_(2) reduction.展开更多
The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-b...The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-based electrocatalyst was developed for use in gas-diffusion electrodes(GDE),and the effect of nitrogen(N)doping on the ECR activity of ZnO electrocatalysts was investigated.Initially,a ZnO nanosheet was prepared via the hydrothermal method,and nitridation was performed at different times to control the N-doping content.With an increase in the N-doping content,the morphological properties of the nanosheet changed significantly,namely,the 2D nanosheets transformed into irregularly shaped nanoparticles.Furthermore,the ECR performance of Zn O electrocatalysts with different N-doping content was assessed in 1.0 M KHCO_(3) electrolyte using a gas-diffusion electrode-based ECR cell.While the ECR activity increased after a small amount of N doping,it decreased for higher N doping content.Among them,the N:ZnO-1 h electrocatalysts showed the best CO selectivity,with a faradaic efficiency(FE_(CO))of 92.7%at-0.73 V vs.reversible hydrogen electrode(RHE),which was greater than that of an undoped Zn O electrocatalyst(FE_(CO)of 63.4%at-0.78 V_(RHE)).Also,the N:ZnO-1 h electrocatalyst exhibited outstanding durability for 16 h,with a partial current density of-92.1 mA cm^(-2).This improvement of N:ZnO-1 h electrocatalyst can be explained by density functional theory calculations,demonstrating that this improvement of N:ZnO-1 h electrocatalyst comes from(ⅰ)the optimized active sites lowering the free energy barrier for the rate-determining step(RDS),and(ⅱ)the modification of electronic structure enhancing the electron transfer rate by N doping.展开更多
Nafion as a universal polymer ionomer was widely applied for nanocatalysts electrode preparation.However,the effect of Nafion on electrocatalytic performance was often overlooked,especially for CO_(2)electrolysis.Here...Nafion as a universal polymer ionomer was widely applied for nanocatalysts electrode preparation.However,the effect of Nafion on electrocatalytic performance was often overlooked,especially for CO_(2)electrolysis.Herein,the key roles of Nafion for CO_(2)RR were systematically studied on Cu nanoparticles(NPs)electrocatalyst.We found that Nafion modifier not only inhibit hydrogen evolution reaction(HER)by decreasing the accessibility of H_(2)O from electrolyte to Cu NPs,and increase the CO_(2)concentration at electrocatalyst interface for enhancing the CO_(2)mass transfer process,but also activate CO_(2)molecule by Lewis acid-base interaction between Nafion and CO_(2)to accelerate the formation of^(*)CO,which favor of C–C coupling for boosting C_(2)product generation.Owing to these features,the HER selectivity was suppressed from 40.6%to 16.8%on optimal Cu@Nafion electrode at-1.2 V versus reversible hydrogen electrode(RHE),and as high as 73.5%faradaic efficiencies(FEs)of C_(2)products were achieved at the same applied potential,which was 2.6 times higher than that on bare Cu electrode(~28.3%).In addition,Nafion also contributed to the long-term stability by hinder Cu NPs morphology reconstruction.Thus,this work provides insights into the impact of Nafion on electrocatalytic CO_(2)RR performance.展开更多
The photocatalytic conversion of CO_(2)into solar‐powered fuels is viewed as a forward‐looking strategy to address energy scarcity and global warming.This work demonstrated the selective photoreduction of CO_(2)to C...The photocatalytic conversion of CO_(2)into solar‐powered fuels is viewed as a forward‐looking strategy to address energy scarcity and global warming.This work demonstrated the selective photoreduction of CO_(2)to CO using ultrathin Bi_(12)O_(17)Cl_(2)nanosheets decorated with hydrothermally synthesized bismuth clusters and oxygen vacancies(OVs).The characterizations revealed that the coexistences of OVs and Bi clusters generated in situ contributed to the high efficiency of CO_(2)–CO conversion(64.3μmol g^(−1)h^(−1))and perfect selectivity.The OVs on the facet(001)of the ultrathin Bi_(12)O_(17)Cl_(2)nanosheets serve as sites for CO_(2)adsorption and activation sites,capturing photoexcited electrons and prolonging light absorption due to defect states.In addition,the Bi‐cluster generated in situ offers the ability to trap holes and the surface plasmonic resonance effect.This study offers great potential for the construction of semiconductor hybrids as multiphotocatalysts,capable of being used for the elimination and conversion of CO_(2)in terms of energy and environment.展开更多
Developing bimetallic catalysts is an effective strategy for enhancing the activity and selectivity of electrochemical CO_(2) reduction reactions,where understanding the structure-activity relationship is essential fo...Developing bimetallic catalysts is an effective strategy for enhancing the activity and selectivity of electrochemical CO_(2) reduction reactions,where understanding the structure-activity relationship is essential for catalyst design.Herein,we prepared two Cu-Ag bimetallic catalysts with Ag nanoparticles attached to the top or the bottom of Cu nanowires.When tested in a flow cell,the Cu-Ag catalyst with Ag nanoparticles on the bottom achieved a faradaic efficiency of 54%for ethylene production,much higher than the catalyst with Ag nanoparticles on the top.The catalysts were further studied in the H-cell and zero-gap MEA cell.It was found that placing the two metals in the intensified reaction zone is crucial to triggering the tandem reaction of bimetallic catalysts.Our work elucidates the structure-activity relationship of bimetallic catalysts for CO_(2) reduction and demonstrates the importance of considering both catalyst structures and cell characteristics to achieve high activity and selectivity.展开更多
Atomically-dispersed metal-based materials represent an emerging class of photocatalysts attributed to their high catalytic activity,abundant surface active sites,and efficient charge separation.Nevertheless,the roles...Atomically-dispersed metal-based materials represent an emerging class of photocatalysts attributed to their high catalytic activity,abundant surface active sites,and efficient charge separation.Nevertheless,the roles of different forms of atomically-dispersed metals(i.e.,single-atoms and atomic clusters)in photocatalytic reactions remain ambiguous.Herein,we developed an ethylenediamine(EDA)-assisted reduction method to controllably synthesize atomically dispersed Au in the forms of Au single atoms(Au_(SA)),Au clusters(Au_(C)),and a mixed-phase of Au_(SA)and Au_(C)(Au_(SA+C))on CdS.In addition,we elucidate the synergistic effect of Au_(SA)and Au_(C)in enhancing the photocatalytic performance of CdS substrates for simultaneous CO_(2)reduction and aryl alcohol oxidation.Specifically,Au_(SA)can effectively lower the energy barrier for the CO_(2)→*COOH conversion,while Au_(C)can enhance the adsorption of alcohols and reduce the energy barrier for dehydrogenation.As a result,the Au_(SA)and Au_(C)co-loaded CdS show impressive overall photocatalytic CO_(2)conversion performance,achieving remarkable CO and BAD production rates of 4.43 and 4.71 mmol g^(−1)h^(−1),with the selectivities of 93%and 99%,respectively.More importantly,the solar-to-chemical conversion efficiency of Au_(SA+C)/CdS reaches 0.57%,which is over fivefold higher than the typical solar-to-biomass conversion efficiency found in nature(ca.0.1%).This study comprehensively describes the roles of different forms of atomically-dispersed metals and their synergistic effects in photocatalytic reactions,which is anticipated to pave a new avenue in energy and environmental applications.展开更多
Coal-fired power plants are a major carbon source in China. In order to assess the evaluation of China's carbon reduction progress with the promise made on the Paris Agreement, it is crucial to monitor the carbon ...Coal-fired power plants are a major carbon source in China. In order to assess the evaluation of China's carbon reduction progress with the promise made on the Paris Agreement, it is crucial to monitor the carbon flux intensity from coal-fired power plants. Previous studies have calculated CO_(2) emissions from point sources based on Orbiting Carbon Observatory-2 and-3(OCO-2 and OCO-3) satellite measurements, but the factors affecting CO_(2) flux estimations are uncertain. In this study, we employ a Gaussian Plume Model to estimate CO_(2) emissions from three power plants in China based on OCO-3 XCO_(2) measurements. Moreover, flux uncertainties resulting from wind information, background values,satellite CO_(2) measurements, and atmospheric stability are discussed. This study highlights the CO_(2) flux uncertainty derived from the satellite measurements. Finally, satellite-based CO_(2) emission estimates are compared to bottom-up inventories.The satellite-based CO_(2) emission estimates at the Tuoketuo and Nongliushi power plants are ~30 and ~10 kt d^(-1) smaller than the Open-Data Inventory for Anthropogenic Carbon dioxide(ODIAC) respectively, but ~10 kt d^(-1) larger than the ODIAC at Baotou.展开更多
The activity and selectivity of electrocatalytic CO_(2)reduction reaction(CO_(2)RR)to C_(2)products on metal catalysts can be regulated by molecular surfactants.However,the mechanism behind it remains elusive and deba...The activity and selectivity of electrocatalytic CO_(2)reduction reaction(CO_(2)RR)to C_(2)products on metal catalysts can be regulated by molecular surfactants.However,the mechanism behind it remains elusive and debatable.Herein,copper nanowires(Cu NWs)were fabricated and decorated with cobalt phthalocyanine(CoPc).The electronic interaction between the Cu NWs,CoPc,CO_(2) and CO_(2)RR intermediates were explored by density functional theory(DFT)calculations.It was found that the selectivity and activity of CO_(2)RR towards C_(2)products on Cu NWs were considerably enhanced from 35.2%to 69.9%by surface decoration of CoPc.DFT calculations revealed that CO_(2)RR can proceed in the interphase between Cu substrate and CoPc,and the CO_(2)RR intermediates could synergistically bond with both Cu and Co metal centre in CuNWs-CoPc,which favours the adsorption of CO_(2),CO and CO_(2)RR intermediates,thus reducing the free energy for CO-COcoupling towards C_(2)products.The synergistic interaction was further extended to phthalocyanine(Pc)and other metal phthalocyanine derivatives(MPc),where a relatively weaker synergistic interaction of COintermediates with MPc and Cu substrate and only a slight enhancement of CO_(2)RR towards C_(2) products were observed.This study demonstrates a synergistic catalysis pathway for CO_(2)RR,a novel perspective in interpreting the role of CoPc in enhancing the activity and selectivity of CO_(2)RR on Cu NWs,in contrast to the conventional tandem catalysis mechanism.展开更多
Metal halide perovskites(MHP)are potential candidates for the photocatalytic reduction of CO_(2)due to their long photogenerated carrier lifetime and charge diffusion length.However,the conventional long-chain ligand ...Metal halide perovskites(MHP)are potential candidates for the photocatalytic reduction of CO_(2)due to their long photogenerated carrier lifetime and charge diffusion length.However,the conventional long-chain ligand impedes the adsorption and activation of CO_(2)molecules in practical applications.Here,a ligand modulation technology is employed to enhance the photocatalytic CO_(2)reduction activity of lead-free Cs_(2)AgInCl_(6)microcrystals(MCs).The Cs_(2)AgInCl_(6)MCs passivated by Oleic acid(OLA)and Octanoic acid(OCA)are used for photocatalytic CO_(2)reduction.The results show that the surface defects and electronic properties of Cs_(2)AgInCl_(6)MCs can be adjusted through ligand modulation.Compared with the OLA-Cs_(2)AgInCl_(6),the OCA-Cs_(2)AgInCl_(6)catalyst demonstrated a significant improvement in the catalytic yield of CO and CH_(4).The CO and CH_(4)catalytic yields of OCA-Cs_(2)AgInCl_(6)reached 171.88 and34.15μmol g^(-1)h^(-1)which were 2.03 and 12.98 times higher than those of OLA-Cs_(2)AgInCl_(6),and the total electron consumption rate of OCA-Cs_(2)AgInCl_(6)was 615.2μmol g^(-1)h^(-1)which was 3.25 times higher than that of OLA-Cs_(2)AgInCl_(6).Furthermore,in situ diffuse reflectance infrared Fourier transform spectra revealed the enhancement of photocatalytic activity in Cs_(2)AgInCl_(6)MCs induced by ligand modulation.This study illustrates the potential of lead-free Cs_(2)AgInCl_(6)MCs for efficient photocatalytic CO_(2)reduction and provides a ligand modulation strategy for the active promotion of MHP photocatalysts.展开更多
The development of earth-abundant electrocatalysts with high performance for electrochemical CO_(2)reduction(ECR)is of great significance.Cu-based catalysts have been widely investigated for ECR due to their unique ab...The development of earth-abundant electrocatalysts with high performance for electrochemical CO_(2)reduction(ECR)is of great significance.Cu-based catalysts have been widely investigated for ECR due to their unique ability to generate various carbonaceous products,but directing selectivity toward one certain product and identifying the real active sites during ECR are still full of challenge.Here,after the incorporation of CdO into CuO,the Cu_(0.5)Cd_(0.5)-O catalyst achieves a 10.3-fold enhancement for CO selectivity in comparison with CuO,and a CO faradic efficiency nearly 90%with a current density around20 mA cm^(-2)could maintain at least 60 h.Interestingly,a wide CO/H_(2)ratio(0.07-10)is reached on Cu_(x)Cd_(1-x)-O catalysts by varying the Cu/Cd ratio,demonstrating the potential of syngas production using such catalysts.The results of ex situ XRD,XPS,and in situ Raman reveal that the real active sites of Cu_(0.5)Cd_(0.5)-O catalysts for CO production during ECR reaction are the reconstructed mixed phases of CuCd alloy and CdCO_(3).In situ FTIR and theoretical calculations further implicate the presence of Cd related species promotes the CO desorption and inhibits the H_(2)evolution,thus leading to an enhanced CO generation.展开更多
Electrochemical CO_(2) reduction to produce value-added chemicals and fuels is one of the research hotspots in the field of energy conversion.The development of efficient catalysts with high conductivity and readily a...Electrochemical CO_(2) reduction to produce value-added chemicals and fuels is one of the research hotspots in the field of energy conversion.The development of efficient catalysts with high conductivity and readily accessible active sites for CO_(2) electroreduction remains challenging yet indispensable.In this work,a reliable poly(ethyleneimine)(PEI)-assisted strategy is developed to prepare a hollow carbon nanocomposite comprising a single-site Ni-modified carbon shell and confined Ni nanoparticles(NPs)(denoted as Ni@NHCS),where PEI not only functions as a mediator to induce the highly dispersed growth of Ni NPs within hollow carbon spheres,but also as a nitrogen precursor to construct highly active atomically-dispersed Ni-Nx sites.Benefiting from the unique structural properties of Ni@NHCS,the aggregation and exposure of Ni NPs can be effectively prevented,while the accessibility of abundant catalytically active Ni-Nx sites can be ensured.As a result,Ni@NHCS exhibits a high CO partial current density of 26.9 mA cm^(-2) and a Faradaic efficiency of 93.0% at-1.0 V vs.RHE,outperforming those of its PEI-free analog.Apart from the excellent activity and selectivity,the shell confinement effect of the hollow carbon sphere endows this catalyst with long-term stability.The findings here are anticipated to help understand the structure-activity relationship in Ni-based carbon catalyst systems for electrocatalytic CO_(2) reduction.Furthermore,the PEI-assisted synthetic concept is potentially applicable to the preparation of high-performance metal-based nanoconfined materials tailored for diverse energy conversion applications and beyond.展开更多
Combination of CO_(2) capture using inorganic alkali with subsequently electrochemical conversion of the resultant HCO_(3)^(-)to high-value chemicals is a promising route of low cost and high efficiency.The electroche...Combination of CO_(2) capture using inorganic alkali with subsequently electrochemical conversion of the resultant HCO_(3)^(-)to high-value chemicals is a promising route of low cost and high efficiency.The electrochemical reduction of HCO_(3)^(-)is challenging due to the inaccessible of negatively charged molecular groups to the electrode surface.Herein,we adopt a comprehensive strategy to tackle this challenge,i.e.,cascade of in situ chemical conversion of HCO_(3)^(-)to CO_(2) and CO_(2) electrochemical reduction in a flow cell.With a tailored Ni-N-S single atom catalyst(SACs),where sulfur(S)atoms located in the second shell of Ni center,the CO_(2)electroreduction(CO_(2)ER)to CO is boosted.The experimental results and density functional theory(DFT)calculations reveal that the introduction of S increases the p electron density of N atoms near Ni atom,thereby stabilizing^(*)H over N and boosting the first proton coupled electron transfer process of CO_(2)ER,i.e.,^(*)+e^(-)+^(*)H+^(*)CO_(2)→^(*)COOH.As a result,the obtained catalyst exhibits a high faradaic efficiency(FE_(CO)~98%)and a low overpotential of 425 mV for CO production as well as a superior turnover frequency(TOF)of 47397 h^(-1),outcompeting most of the reported Ni SACs.More importantly,an extremely high FECOof 90%is achieved at 50 mA cm^(-2)in the designed membrane electrode assembly(MEA)cascade electrolyzer fed with liquid bicarbonate.This work not only highlights the significant role of the second coordination on the first coordination shell of the central metal for CO_(2)ER,but also provides an alternative and feasible strategy to realize the electrochemical conversion of HCO_(3)^(-)to high-value chemicals.展开更多
Electrochemical reduction of CO_(2) to syngas(CO and H_(2))offers an efficient way to mitigate carbon emissions and store intermittent renewable energy in chemicals.Herein,the hierarchical one‐dimensional/three‐dime...Electrochemical reduction of CO_(2) to syngas(CO and H_(2))offers an efficient way to mitigate carbon emissions and store intermittent renewable energy in chemicals.Herein,the hierarchical one‐dimensional/three‐dimensional nitrogen‐doped porous carbon(1D/3D NPC)is prepared by carbonizing the composite of Zn‐MOF‐74 crystals in situ grown on a commercial melamine sponge(MS),for electrochemical CO_(2) reduction reaction(CO_(2)RR).The 1D/3D NPC exhibits a high CO/H_(2) ratio(5.06)and CO yield(31 mmol g^(−1)h^(−1))at−0.55 V,which are 13.7 times and 21.4 times those of 1D porous carbon(derived from Zn‐MOF‐74)and N‐doped carbon(carbonized by MS),respectively.This is attributed to the unique spatial environment of 1D/3D NPC,which increases the adsorption capacity of CO_(2) and promotes electron transfer from the 3D N‐doped carbon framework to 1D carbon,improving the reaction kinetics of CO_(2)RR.Experimental results and charge density difference plots indicate that the active site of CO_(2)RR is the positively charged carbon atom adjacent to graphitic N on 1D carbon and the active site of HER is the pyridinic N on 1D carbon.The presence of pyridinic N and pyrrolic N reduces the number of electron transfer,decreasing the reaction kinetics and the activity of CO_(2)RR.The CO/H_(2) ratio is related to the distribution of N species and the specific surface area,which are determined by the degree of spatial confinement effect.The CO/H_(2) ratios can be regulated by adjusting the carbonization temperature to adjust the degree of spatial confinement effect.Given the low cost of feedstock and easy strategy,1D/3D NPC catalysts have great potential for industrial application.展开更多
At room temperature,the conversion of greenhouse gases into valuable chemicals using metal-free catalysts for dry reforming of methane(DRM) is quite promising and challenging.Herein,we developed a novel covalent organ...At room temperature,the conversion of greenhouse gases into valuable chemicals using metal-free catalysts for dry reforming of methane(DRM) is quite promising and challenging.Herein,we developed a novel covalent organic porous polymer (TPE-COP) with rapid charge separation of the electron–hole pairs for DRM driven by visible light at room temperature,which can efficiently generate syngas (CO and H_(2)).Both electron donor (tris(4-aminophenyl)amine,TAPA) and acceptor (4,4',4'',4'''-((1 E,1'E,1''E,1'''E)-(ethene-1,1,2,2-tetrayltetrakis (benzene-4,1-diyl))tetrakis (ethene-2,1-diyl))tetrakis (1-(4-formylbenzyl)quinolin-1-ium),TPE-CHO) were existed in TPE-COP,in which the push–pull effect between them promoted the separation of photogenerated electron–hole,thus greatly improving the photocatalytic activity.Density functional theory (DFT) simulation results show that TPE-COP can form charge-separating species under light irradiation,leading to electrons accumulation in TPE-CHO unit and holes in TAPA,and thus efficiently initiating DRM.After 20 h illumination,the photocatalytic results show that the yields reach 1123.6 and 30.8μmol g^(-1)for CO and H_(2),respectively,which are significantly higher than those of TPE-CHO small molecules.This excellent result is mainly due to the increase of specific surface area,the enhancement of light absorption capacity,and the improvement of photoelectron-generating efficiency after the formation of COP.Overall,this work contributes to understanding the advantages of COP materials for photocatalysis and fundamentally pushes metal-free catalysts into the door of DRM field.展开更多
Photocatalytic CO_(2)reduction to produce high value-added carbon-based fuel has been proposed as a promising approach to mitigate global warming issues.However,the conversion efficiency and product selectivity are st...Photocatalytic CO_(2)reduction to produce high value-added carbon-based fuel has been proposed as a promising approach to mitigate global warming issues.However,the conversion efficiency and product selectivity are still low due to the sluggish dynamics of transfer processes involved in proton-assisted multi-electron reactions.Lowering the formation energy barriers of intermediate products is an effective method to enhance the selectivity and productivity of final products.In this study,we aim to regulate the surface electronic structure of Bi_(2)WO_(6)by doping surface chlorine atoms to achieve effective photocatalytic CO_(2)reduction.Surface Cl atoms can enhance the absorption ability of light,affect its energy band structure and promote charge separation.Combined with DFT calculations,it is revealed that surface Cl atoms can not only change the surface charge distribution which affects the competitive adsorption of H_(2)O and CO_(2),but also lower the formation energy barrier of intermediate products to generate more intermediate*COOH,thus facilitating CO production.Overall,this study demonstrates a promising surface halogenation strategy to enhance the photocatalytic CO_(2)reduction activity of a layered structure Bi-based catalyst.展开更多
Efficient photocatalytic reduction of CO_(2) to high-calorific-value CH4,an ideal target product,is a blueprint for C_(1)industry relevance and carbon neutrality,but it also faces great challenges.Herein,we demonstrat...Efficient photocatalytic reduction of CO_(2) to high-calorific-value CH4,an ideal target product,is a blueprint for C_(1)industry relevance and carbon neutrality,but it also faces great challenges.Herein,we demonstrate unprecedented hybrid SiC photocatalysts modified by Fe-based cocatalyst,which are prepared via a facile impregnation-reduction method,featuring an optimized local electronic structure.It exhibits a superior photocatalytic carbon-based products yield of 30.0μmol g^(−1) h^(−1) and achieves a record CH_(4) selectivity of up to 94.3%,which highlights the effectiveness of electron-rich Fe cocatalyst for boosting photocatalytic performance and selectivity.Specifically,the synergistic effects of directional migration of photogenerated electrons and strongπ-back bonding on low-valence Fe effectively strengthen the adsorption and activation of reactants and intermediates in the CO_(2)→CH_(4) pathway.This study inspires an effective strategy for enhancing the multielectron reduction capacity of semiconductor photocatalysts with low-cost Fe instead of noble metals as cocatalysts.展开更多
Atomically‐dispersed copper sites coordinated with nitrogen‐doped carbon(Cu–N–C)can provide novel possibilities to enable highly selective and active electrochemical CO_(2) reduction reactions.However,the construc...Atomically‐dispersed copper sites coordinated with nitrogen‐doped carbon(Cu–N–C)can provide novel possibilities to enable highly selective and active electrochemical CO_(2) reduction reactions.However,the construction of optimal local electronic structures for nitrogen‐coordinated Cu sites(Cu–N_(4))on carbon remains challenging.Here,we synthesized the Cu–N–C catalysts with atomically‐dispersed edge‐hosted Cu–N_(4) sites(Cu–N_(4)C_(8))located in a micropore between two graphitic sheets via a facile method to control the concentration of metal precursor.Edge‐hosted Cu–N_(4)C_(8) catalysts outperformed the previously reported M–N–C catalysts for CO_(2)‐to‐CO conversion,achieving a maximum CO Faradaic efficiency(FECO)of 96%,a CO current density of–8.97 mA cm^(–2) at–0.8 V versus reversible hydrogen electrode(RHE),and over FECO of 90%from–0.6 to–1.0 V versus RHE.Computational studies revealed that the micropore of the graphitic layer in edge‐hosted Cu–N_(4)C_(8) sites causes the d‐orbital energy level of the Cu atom to shift upward,which in return decreases the occupancy of antibonding states in the*COOH binding.This research suggests new insights into tailoring the locally coordinated structure of the electrocatalyst at the atomic scale to achieve highly selective electrocatalytic reactions.展开更多
基金financial support from the National Natural Science Foundation of China(No.22272038)the Science and Technology Planning Project of Guangzhou City(No.2023A03J0026)。
文摘Developing suitable photocatalysts and understanding their intrinsic catalytic mechanism remain key challenges in the pursuit of highly active,good selective,and long-term stable photocatalytic CO_(2)reduction(PCO_(2)R)systems.Herein,monoclinic Cu_(2)(OH)_(2)CO_(3)is firstly proven to be a new class of photocatalyst,which has excellent catalytic stability and selectivity for PCO_(2)R in the absence of any sacrificial agent and cocatalysts.Based on a Cu_(2)(OH)_(2)^(13)CO_(3)photocatalyst and 13CO_(2)two-sided^(13)C isotopic tracer strategy,and combined with in situ diffused reflectance infrared Fourier transform spectroscopy(DRIFTS)analysis and density functional theory(DFT)calculations,two main CO_(2)transformation routes,and the photo-decomposition and self-restructuring dynamic equilibrium mechanism of Cu_(2)(OH)_(2)CO_(3)are definitely revealed.The PCO_(2)R activity of Cu_(2)(OH)_(2)CO_(3)is comparable to some of state-of-the-art novel photocatalysts.Significantly,the PCO_(2)R properties can be further greatly enhanced by simply combining Cu_(2)(OH)_(2)CO_(3)with typical TiO_(2)to construct composites photocatalyst.The highest CO_(2)and CH_(4)production rates by 7.5 wt%Cu_(2)(OH)_(2)CO_(3)-TiO_(2)reach 16.4μmol g^(-1)h^(-1)and 116.0μmol g^(-1)h^(-1),respectively,which are even higher than that of some of PCO_(2)R systems containing sacrificial agents or precious metals modified photocatalysts.This work provides a better understanding for the PCO_(2)R mechanism at the atomic levels,and also indicates that basic carbonate photocatalysts have broad application potential in the future.
基金funded by the National Natural Science Foundation of China,China (Nos.52272303 and 52073212)the General Program of Municipal Natural Science Foundation of Tianjin,China (Nos.17JCYBJC22700 and 17JCYBJC17000)the State Scholarship Fund of China Scholarship Council,China (Nos.201709345012 and 201706255009)。
文摘The global energy-related CO_(2) emissions have rapidly increased as the world economy heavily relied on fossil fuels.This paper explores the pressing challenge of CO_(2) emissions and highlights the role of porous metal oxide materials in the electrocatalytic reduction of CO_(2)(CO_(2)RR).The focus is on the development of robust and selective catalysts,particularly metal and metal-oxide-based materials.Porous metal oxides offer high surface area,enhancing the accessibility to active sites and improving reaction kinetics.The tunability of these materials allows for tailored catalytic behavior,targeting optimized reaction mechanisms for CO_(2)RR.The work also discusses the various synthesis strategies and identifies key structural and compositional features,addressing challenges like high overpotential,poor selectivity,and low stability.Based on these insights,we suggest avenues for future research on porous metal oxide materials for electrochemical CO_(2) reduction.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) (Grant Nos.2018R1A6A1A03024334,2019R1A2C1007637,2021M3I3A1082880,2021R1I1A1A01044174)the Basic Science Research Capacity Enhancement Project through Korea Basic Science Institute (Grant No.2019R1A6C1010024)。
文摘The discovery of efficient,selective,and stable electrocatalysts can be a key point to produce the largescale chemical fuels via electrochemical CO_(2) reduction(ECR).In this study,an earth-abundant and nontoxic ZnO-based electrocatalyst was developed for use in gas-diffusion electrodes(GDE),and the effect of nitrogen(N)doping on the ECR activity of ZnO electrocatalysts was investigated.Initially,a ZnO nanosheet was prepared via the hydrothermal method,and nitridation was performed at different times to control the N-doping content.With an increase in the N-doping content,the morphological properties of the nanosheet changed significantly,namely,the 2D nanosheets transformed into irregularly shaped nanoparticles.Furthermore,the ECR performance of Zn O electrocatalysts with different N-doping content was assessed in 1.0 M KHCO_(3) electrolyte using a gas-diffusion electrode-based ECR cell.While the ECR activity increased after a small amount of N doping,it decreased for higher N doping content.Among them,the N:ZnO-1 h electrocatalysts showed the best CO selectivity,with a faradaic efficiency(FE_(CO))of 92.7%at-0.73 V vs.reversible hydrogen electrode(RHE),which was greater than that of an undoped Zn O electrocatalyst(FE_(CO)of 63.4%at-0.78 V_(RHE)).Also,the N:ZnO-1 h electrocatalyst exhibited outstanding durability for 16 h,with a partial current density of-92.1 mA cm^(-2).This improvement of N:ZnO-1 h electrocatalyst can be explained by density functional theory calculations,demonstrating that this improvement of N:ZnO-1 h electrocatalyst comes from(ⅰ)the optimized active sites lowering the free energy barrier for the rate-determining step(RDS),and(ⅱ)the modification of electronic structure enhancing the electron transfer rate by N doping.
基金financially supported by the Natural Science Foundation of Guangdong Province (2022A1515012359)the National Natural Science Foundation of China (21902121)+1 种基金the STU Scientific Research Foundation for Talents (NTF21020)the 2020 Li Ka Shing Foundation Cross-Disciplinary Research Grant (2020LKSFG09A)。
文摘Nafion as a universal polymer ionomer was widely applied for nanocatalysts electrode preparation.However,the effect of Nafion on electrocatalytic performance was often overlooked,especially for CO_(2)electrolysis.Herein,the key roles of Nafion for CO_(2)RR were systematically studied on Cu nanoparticles(NPs)electrocatalyst.We found that Nafion modifier not only inhibit hydrogen evolution reaction(HER)by decreasing the accessibility of H_(2)O from electrolyte to Cu NPs,and increase the CO_(2)concentration at electrocatalyst interface for enhancing the CO_(2)mass transfer process,but also activate CO_(2)molecule by Lewis acid-base interaction between Nafion and CO_(2)to accelerate the formation of^(*)CO,which favor of C–C coupling for boosting C_(2)product generation.Owing to these features,the HER selectivity was suppressed from 40.6%to 16.8%on optimal Cu@Nafion electrode at-1.2 V versus reversible hydrogen electrode(RHE),and as high as 73.5%faradaic efficiencies(FEs)of C_(2)products were achieved at the same applied potential,which was 2.6 times higher than that on bare Cu electrode(~28.3%).In addition,Nafion also contributed to the long-term stability by hinder Cu NPs morphology reconstruction.Thus,this work provides insights into the impact of Nafion on electrocatalytic CO_(2)RR performance.
基金Natural Science Foundation of Shandong Province,Grant/Award Number:ZR2022MB106national training program of innovation and entrepreneurship for undergraduates,Grant/Award Number:202210424099National Natural Science Foundation of China,Grant/Award Numbers:21601067,21701057,21905147。
文摘The photocatalytic conversion of CO_(2)into solar‐powered fuels is viewed as a forward‐looking strategy to address energy scarcity and global warming.This work demonstrated the selective photoreduction of CO_(2)to CO using ultrathin Bi_(12)O_(17)Cl_(2)nanosheets decorated with hydrothermally synthesized bismuth clusters and oxygen vacancies(OVs).The characterizations revealed that the coexistences of OVs and Bi clusters generated in situ contributed to the high efficiency of CO_(2)–CO conversion(64.3μmol g^(−1)h^(−1))and perfect selectivity.The OVs on the facet(001)of the ultrathin Bi_(12)O_(17)Cl_(2)nanosheets serve as sites for CO_(2)adsorption and activation sites,capturing photoexcited electrons and prolonging light absorption due to defect states.In addition,the Bi‐cluster generated in situ offers the ability to trap holes and the surface plasmonic resonance effect.This study offers great potential for the construction of semiconductor hybrids as multiphotocatalysts,capable of being used for the elimination and conversion of CO_(2)in terms of energy and environment.
基金the funding support from the National Key Research and Development Program of China(2019YFE0123400)the Tianjin Distinguished Young Scholars Fund(20JCJQJC00260)+4 种基金the Major Science and Technology Project of Anhui Province(202203f07020007)the Anhui Conch Group Co.,Ltdthe“111”Project(B16027)the funding support from the Natural Science Foundation of China(22209081)the fellowship of China Postdoctoral Science Foundation(2021M690082)。
文摘Developing bimetallic catalysts is an effective strategy for enhancing the activity and selectivity of electrochemical CO_(2) reduction reactions,where understanding the structure-activity relationship is essential for catalyst design.Herein,we prepared two Cu-Ag bimetallic catalysts with Ag nanoparticles attached to the top or the bottom of Cu nanowires.When tested in a flow cell,the Cu-Ag catalyst with Ag nanoparticles on the bottom achieved a faradaic efficiency of 54%for ethylene production,much higher than the catalyst with Ag nanoparticles on the top.The catalysts were further studied in the H-cell and zero-gap MEA cell.It was found that placing the two metals in the intensified reaction zone is crucial to triggering the tandem reaction of bimetallic catalysts.Our work elucidates the structure-activity relationship of bimetallic catalysts for CO_(2) reduction and demonstrates the importance of considering both catalyst structures and cell characteristics to achieve high activity and selectivity.
文摘Atomically-dispersed metal-based materials represent an emerging class of photocatalysts attributed to their high catalytic activity,abundant surface active sites,and efficient charge separation.Nevertheless,the roles of different forms of atomically-dispersed metals(i.e.,single-atoms and atomic clusters)in photocatalytic reactions remain ambiguous.Herein,we developed an ethylenediamine(EDA)-assisted reduction method to controllably synthesize atomically dispersed Au in the forms of Au single atoms(Au_(SA)),Au clusters(Au_(C)),and a mixed-phase of Au_(SA)and Au_(C)(Au_(SA+C))on CdS.In addition,we elucidate the synergistic effect of Au_(SA)and Au_(C)in enhancing the photocatalytic performance of CdS substrates for simultaneous CO_(2)reduction and aryl alcohol oxidation.Specifically,Au_(SA)can effectively lower the energy barrier for the CO_(2)→*COOH conversion,while Au_(C)can enhance the adsorption of alcohols and reduce the energy barrier for dehydrogenation.As a result,the Au_(SA)and Au_(C)co-loaded CdS show impressive overall photocatalytic CO_(2)conversion performance,achieving remarkable CO and BAD production rates of 4.43 and 4.71 mmol g^(−1)h^(−1),with the selectivities of 93%and 99%,respectively.More importantly,the solar-to-chemical conversion efficiency of Au_(SA+C)/CdS reaches 0.57%,which is over fivefold higher than the typical solar-to-biomass conversion efficiency found in nature(ca.0.1%).This study comprehensively describes the roles of different forms of atomically-dispersed metals and their synergistic effects in photocatalytic reactions,which is anticipated to pave a new avenue in energy and environmental applications.
基金supported by the Shanghai Sailing Program (Grant No. 22YF1442000)the Key Laboratory of Middle Atmosphere and Global Environment Observation(Grant No. LAGEO-2021-07)+1 种基金the National Natural Science Foundation of China (Grant No. 41975035)Jiaxing University (Grant Nos. 00323027AL and CD70522035)。
文摘Coal-fired power plants are a major carbon source in China. In order to assess the evaluation of China's carbon reduction progress with the promise made on the Paris Agreement, it is crucial to monitor the carbon flux intensity from coal-fired power plants. Previous studies have calculated CO_(2) emissions from point sources based on Orbiting Carbon Observatory-2 and-3(OCO-2 and OCO-3) satellite measurements, but the factors affecting CO_(2) flux estimations are uncertain. In this study, we employ a Gaussian Plume Model to estimate CO_(2) emissions from three power plants in China based on OCO-3 XCO_(2) measurements. Moreover, flux uncertainties resulting from wind information, background values,satellite CO_(2) measurements, and atmospheric stability are discussed. This study highlights the CO_(2) flux uncertainty derived from the satellite measurements. Finally, satellite-based CO_(2) emission estimates are compared to bottom-up inventories.The satellite-based CO_(2) emission estimates at the Tuoketuo and Nongliushi power plants are ~30 and ~10 kt d^(-1) smaller than the Open-Data Inventory for Anthropogenic Carbon dioxide(ODIAC) respectively, but ~10 kt d^(-1) larger than the ODIAC at Baotou.
基金supported by the National Natural Science Foundation of China(U2032151,22272059)。
文摘The activity and selectivity of electrocatalytic CO_(2)reduction reaction(CO_(2)RR)to C_(2)products on metal catalysts can be regulated by molecular surfactants.However,the mechanism behind it remains elusive and debatable.Herein,copper nanowires(Cu NWs)were fabricated and decorated with cobalt phthalocyanine(CoPc).The electronic interaction between the Cu NWs,CoPc,CO_(2) and CO_(2)RR intermediates were explored by density functional theory(DFT)calculations.It was found that the selectivity and activity of CO_(2)RR towards C_(2)products on Cu NWs were considerably enhanced from 35.2%to 69.9%by surface decoration of CoPc.DFT calculations revealed that CO_(2)RR can proceed in the interphase between Cu substrate and CoPc,and the CO_(2)RR intermediates could synergistically bond with both Cu and Co metal centre in CuNWs-CoPc,which favours the adsorption of CO_(2),CO and CO_(2)RR intermediates,thus reducing the free energy for CO-COcoupling towards C_(2)products.The synergistic interaction was further extended to phthalocyanine(Pc)and other metal phthalocyanine derivatives(MPc),where a relatively weaker synergistic interaction of COintermediates with MPc and Cu substrate and only a slight enhancement of CO_(2)RR towards C_(2) products were observed.This study demonstrates a synergistic catalysis pathway for CO_(2)RR,a novel perspective in interpreting the role of CoPc in enhancing the activity and selectivity of CO_(2)RR on Cu NWs,in contrast to the conventional tandem catalysis mechanism.
基金the National Natural Science Foundation of China(Grant No.62375032)the Natural Science Foundation of Chongqing(Grant No.CSTB2023TIADKPX0017)+2 种基金the Open Fund of the State Key Laboratory of High Field Laser Physics(Shanghai Institute of Optics and Fine Mechanics)the China Postdoctoral Science Foundation(Grant No.BX20230355)the Department of Education of Guizhou Province(Guizhou Teaching and Technology[2023]015)。
文摘Metal halide perovskites(MHP)are potential candidates for the photocatalytic reduction of CO_(2)due to their long photogenerated carrier lifetime and charge diffusion length.However,the conventional long-chain ligand impedes the adsorption and activation of CO_(2)molecules in practical applications.Here,a ligand modulation technology is employed to enhance the photocatalytic CO_(2)reduction activity of lead-free Cs_(2)AgInCl_(6)microcrystals(MCs).The Cs_(2)AgInCl_(6)MCs passivated by Oleic acid(OLA)and Octanoic acid(OCA)are used for photocatalytic CO_(2)reduction.The results show that the surface defects and electronic properties of Cs_(2)AgInCl_(6)MCs can be adjusted through ligand modulation.Compared with the OLA-Cs_(2)AgInCl_(6),the OCA-Cs_(2)AgInCl_(6)catalyst demonstrated a significant improvement in the catalytic yield of CO and CH_(4).The CO and CH_(4)catalytic yields of OCA-Cs_(2)AgInCl_(6)reached 171.88 and34.15μmol g^(-1)h^(-1)which were 2.03 and 12.98 times higher than those of OLA-Cs_(2)AgInCl_(6),and the total electron consumption rate of OCA-Cs_(2)AgInCl_(6)was 615.2μmol g^(-1)h^(-1)which was 3.25 times higher than that of OLA-Cs_(2)AgInCl_(6).Furthermore,in situ diffuse reflectance infrared Fourier transform spectra revealed the enhancement of photocatalytic activity in Cs_(2)AgInCl_(6)MCs induced by ligand modulation.This study illustrates the potential of lead-free Cs_(2)AgInCl_(6)MCs for efficient photocatalytic CO_(2)reduction and provides a ligand modulation strategy for the active promotion of MHP photocatalysts.
基金financially supported by the National Natural Science Foundation of China with grant number of 22172082 and 21978137。
文摘The development of earth-abundant electrocatalysts with high performance for electrochemical CO_(2)reduction(ECR)is of great significance.Cu-based catalysts have been widely investigated for ECR due to their unique ability to generate various carbonaceous products,but directing selectivity toward one certain product and identifying the real active sites during ECR are still full of challenge.Here,after the incorporation of CdO into CuO,the Cu_(0.5)Cd_(0.5)-O catalyst achieves a 10.3-fold enhancement for CO selectivity in comparison with CuO,and a CO faradic efficiency nearly 90%with a current density around20 mA cm^(-2)could maintain at least 60 h.Interestingly,a wide CO/H_(2)ratio(0.07-10)is reached on Cu_(x)Cd_(1-x)-O catalysts by varying the Cu/Cd ratio,demonstrating the potential of syngas production using such catalysts.The results of ex situ XRD,XPS,and in situ Raman reveal that the real active sites of Cu_(0.5)Cd_(0.5)-O catalysts for CO production during ECR reaction are the reconstructed mixed phases of CuCd alloy and CdCO_(3).In situ FTIR and theoretical calculations further implicate the presence of Cd related species promotes the CO desorption and inhibits the H_(2)evolution,thus leading to an enhanced CO generation.
文摘Electrochemical CO_(2) reduction to produce value-added chemicals and fuels is one of the research hotspots in the field of energy conversion.The development of efficient catalysts with high conductivity and readily accessible active sites for CO_(2) electroreduction remains challenging yet indispensable.In this work,a reliable poly(ethyleneimine)(PEI)-assisted strategy is developed to prepare a hollow carbon nanocomposite comprising a single-site Ni-modified carbon shell and confined Ni nanoparticles(NPs)(denoted as Ni@NHCS),where PEI not only functions as a mediator to induce the highly dispersed growth of Ni NPs within hollow carbon spheres,but also as a nitrogen precursor to construct highly active atomically-dispersed Ni-Nx sites.Benefiting from the unique structural properties of Ni@NHCS,the aggregation and exposure of Ni NPs can be effectively prevented,while the accessibility of abundant catalytically active Ni-Nx sites can be ensured.As a result,Ni@NHCS exhibits a high CO partial current density of 26.9 mA cm^(-2) and a Faradaic efficiency of 93.0% at-1.0 V vs.RHE,outperforming those of its PEI-free analog.Apart from the excellent activity and selectivity,the shell confinement effect of the hollow carbon sphere endows this catalyst with long-term stability.The findings here are anticipated to help understand the structure-activity relationship in Ni-based carbon catalyst systems for electrocatalytic CO_(2) reduction.Furthermore,the PEI-assisted synthetic concept is potentially applicable to the preparation of high-performance metal-based nanoconfined materials tailored for diverse energy conversion applications and beyond.
基金financially supported by the Natural Science Foundation of Shandong Province (ZR2020QB132,ZR2020MB025)the Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure (SKL202108SIC)the Taishan Scholar Program of Shandong Province (ts201712046)。
文摘Combination of CO_(2) capture using inorganic alkali with subsequently electrochemical conversion of the resultant HCO_(3)^(-)to high-value chemicals is a promising route of low cost and high efficiency.The electrochemical reduction of HCO_(3)^(-)is challenging due to the inaccessible of negatively charged molecular groups to the electrode surface.Herein,we adopt a comprehensive strategy to tackle this challenge,i.e.,cascade of in situ chemical conversion of HCO_(3)^(-)to CO_(2) and CO_(2) electrochemical reduction in a flow cell.With a tailored Ni-N-S single atom catalyst(SACs),where sulfur(S)atoms located in the second shell of Ni center,the CO_(2)electroreduction(CO_(2)ER)to CO is boosted.The experimental results and density functional theory(DFT)calculations reveal that the introduction of S increases the p electron density of N atoms near Ni atom,thereby stabilizing^(*)H over N and boosting the first proton coupled electron transfer process of CO_(2)ER,i.e.,^(*)+e^(-)+^(*)H+^(*)CO_(2)→^(*)COOH.As a result,the obtained catalyst exhibits a high faradaic efficiency(FE_(CO)~98%)and a low overpotential of 425 mV for CO production as well as a superior turnover frequency(TOF)of 47397 h^(-1),outcompeting most of the reported Ni SACs.More importantly,an extremely high FECOof 90%is achieved at 50 mA cm^(-2)in the designed membrane electrode assembly(MEA)cascade electrolyzer fed with liquid bicarbonate.This work not only highlights the significant role of the second coordination on the first coordination shell of the central metal for CO_(2)ER,but also provides an alternative and feasible strategy to realize the electrochemical conversion of HCO_(3)^(-)to high-value chemicals.
基金National Natural Science Foundation of China,Grant/Award Numbers:51873085,52071171,52202248The Australian Government through the Cooperative Research Centres Projects,Grant/Award Number:CRCPⅩⅢ000077+10 种基金Linkage Project,Grant/Award Numbers:LP210100467,LP210200345,LP210200504,LP220100088Natural Science Foundation of Liaoning Province‐Outstanding Youth Foundation,Grant/Award Number:2022‐YQ‐14Discovery Project,Grant/Award Number:DP220100603China Scholarship Council(CSC Scholarship),Grant/Award Number:202006800009Liaoning Revitalization Talents Program,Grant/Award Number:XLYC2007056Australian Research Council(ARC)through Future Fellowship,Grant/Award Numbers:FT210100298,FT210100806Shenyang Science and Technology Project,Grant/Award Number:21‐108‐9‐04Industrial Transformation Training Centre schemes,Grant/Award Number:IC180100005Natural Science Foundation of Liaoning Province,Grant/Award Number:2020‐MS‐137Key Research Project of Department of Education of Liaoning Province,Grant/Award Number:LJKZZ20220015Liaoning BaiQianWan Talents Program,Grant/Award Number:LNBQW2018B0048。
文摘Electrochemical reduction of CO_(2) to syngas(CO and H_(2))offers an efficient way to mitigate carbon emissions and store intermittent renewable energy in chemicals.Herein,the hierarchical one‐dimensional/three‐dimensional nitrogen‐doped porous carbon(1D/3D NPC)is prepared by carbonizing the composite of Zn‐MOF‐74 crystals in situ grown on a commercial melamine sponge(MS),for electrochemical CO_(2) reduction reaction(CO_(2)RR).The 1D/3D NPC exhibits a high CO/H_(2) ratio(5.06)and CO yield(31 mmol g^(−1)h^(−1))at−0.55 V,which are 13.7 times and 21.4 times those of 1D porous carbon(derived from Zn‐MOF‐74)and N‐doped carbon(carbonized by MS),respectively.This is attributed to the unique spatial environment of 1D/3D NPC,which increases the adsorption capacity of CO_(2) and promotes electron transfer from the 3D N‐doped carbon framework to 1D carbon,improving the reaction kinetics of CO_(2)RR.Experimental results and charge density difference plots indicate that the active site of CO_(2)RR is the positively charged carbon atom adjacent to graphitic N on 1D carbon and the active site of HER is the pyridinic N on 1D carbon.The presence of pyridinic N and pyrrolic N reduces the number of electron transfer,decreasing the reaction kinetics and the activity of CO_(2)RR.The CO/H_(2) ratio is related to the distribution of N species and the specific surface area,which are determined by the degree of spatial confinement effect.The CO/H_(2) ratios can be regulated by adjusting the carbonization temperature to adjust the degree of spatial confinement effect.Given the low cost of feedstock and easy strategy,1D/3D NPC catalysts have great potential for industrial application.
基金supported by National Natural Science Foundation of China (Nos. 22274039 and 22178089)Hunan Provincial Innovation Foundation for Postgraduate (No.CX20220392)。
文摘At room temperature,the conversion of greenhouse gases into valuable chemicals using metal-free catalysts for dry reforming of methane(DRM) is quite promising and challenging.Herein,we developed a novel covalent organic porous polymer (TPE-COP) with rapid charge separation of the electron–hole pairs for DRM driven by visible light at room temperature,which can efficiently generate syngas (CO and H_(2)).Both electron donor (tris(4-aminophenyl)amine,TAPA) and acceptor (4,4',4'',4'''-((1 E,1'E,1''E,1'''E)-(ethene-1,1,2,2-tetrayltetrakis (benzene-4,1-diyl))tetrakis (ethene-2,1-diyl))tetrakis (1-(4-formylbenzyl)quinolin-1-ium),TPE-CHO) were existed in TPE-COP,in which the push–pull effect between them promoted the separation of photogenerated electron–hole,thus greatly improving the photocatalytic activity.Density functional theory (DFT) simulation results show that TPE-COP can form charge-separating species under light irradiation,leading to electrons accumulation in TPE-CHO unit and holes in TAPA,and thus efficiently initiating DRM.After 20 h illumination,the photocatalytic results show that the yields reach 1123.6 and 30.8μmol g^(-1)for CO and H_(2),respectively,which are significantly higher than those of TPE-CHO small molecules.This excellent result is mainly due to the increase of specific surface area,the enhancement of light absorption capacity,and the improvement of photoelectron-generating efficiency after the formation of COP.Overall,this work contributes to understanding the advantages of COP materials for photocatalysis and fundamentally pushes metal-free catalysts into the door of DRM field.
基金supported by the National Natural Science Foundation of China(Grant No.51708078)Natural Science Foundation of Chongqing(Grant No.CSTB2022NSCQ-MSX0815)+2 种基金Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202200542)the Chongqing Innovative Research Group Project(Grant No.CXQT21015)Foundation of Chongqing Normal University(22XLB022).
文摘Photocatalytic CO_(2)reduction to produce high value-added carbon-based fuel has been proposed as a promising approach to mitigate global warming issues.However,the conversion efficiency and product selectivity are still low due to the sluggish dynamics of transfer processes involved in proton-assisted multi-electron reactions.Lowering the formation energy barriers of intermediate products is an effective method to enhance the selectivity and productivity of final products.In this study,we aim to regulate the surface electronic structure of Bi_(2)WO_(6)by doping surface chlorine atoms to achieve effective photocatalytic CO_(2)reduction.Surface Cl atoms can enhance the absorption ability of light,affect its energy band structure and promote charge separation.Combined with DFT calculations,it is revealed that surface Cl atoms can not only change the surface charge distribution which affects the competitive adsorption of H_(2)O and CO_(2),but also lower the formation energy barrier of intermediate products to generate more intermediate*COOH,thus facilitating CO production.Overall,this study demonstrates a promising surface halogenation strategy to enhance the photocatalytic CO_(2)reduction activity of a layered structure Bi-based catalyst.
基金supported by the National Natural Science Foundation of China(Grant No.22072022)the Natural Science Foundation of Fujian Province(2021L3003)the Science Foundation of Shandong Province(ZR2019BB065).
文摘Efficient photocatalytic reduction of CO_(2) to high-calorific-value CH4,an ideal target product,is a blueprint for C_(1)industry relevance and carbon neutrality,but it also faces great challenges.Herein,we demonstrate unprecedented hybrid SiC photocatalysts modified by Fe-based cocatalyst,which are prepared via a facile impregnation-reduction method,featuring an optimized local electronic structure.It exhibits a superior photocatalytic carbon-based products yield of 30.0μmol g^(−1) h^(−1) and achieves a record CH_(4) selectivity of up to 94.3%,which highlights the effectiveness of electron-rich Fe cocatalyst for boosting photocatalytic performance and selectivity.Specifically,the synergistic effects of directional migration of photogenerated electrons and strongπ-back bonding on low-valence Fe effectively strengthen the adsorption and activation of reactants and intermediates in the CO_(2)→CH_(4) pathway.This study inspires an effective strategy for enhancing the multielectron reduction capacity of semiconductor photocatalysts with low-cost Fe instead of noble metals as cocatalysts.
基金National Research Foundation of Korea,Grant/Award Numbers:NRF‐2019M3D1A1079303,NRF‐2021R1A2C1011415,NRF‐2021R1A2C3004019。
文摘Atomically‐dispersed copper sites coordinated with nitrogen‐doped carbon(Cu–N–C)can provide novel possibilities to enable highly selective and active electrochemical CO_(2) reduction reactions.However,the construction of optimal local electronic structures for nitrogen‐coordinated Cu sites(Cu–N_(4))on carbon remains challenging.Here,we synthesized the Cu–N–C catalysts with atomically‐dispersed edge‐hosted Cu–N_(4) sites(Cu–N_(4)C_(8))located in a micropore between two graphitic sheets via a facile method to control the concentration of metal precursor.Edge‐hosted Cu–N_(4)C_(8) catalysts outperformed the previously reported M–N–C catalysts for CO_(2)‐to‐CO conversion,achieving a maximum CO Faradaic efficiency(FECO)of 96%,a CO current density of–8.97 mA cm^(–2) at–0.8 V versus reversible hydrogen electrode(RHE),and over FECO of 90%from–0.6 to–1.0 V versus RHE.Computational studies revealed that the micropore of the graphitic layer in edge‐hosted Cu–N_(4)C_(8) sites causes the d‐orbital energy level of the Cu atom to shift upward,which in return decreases the occupancy of antibonding states in the*COOH binding.This research suggests new insights into tailoring the locally coordinated structure of the electrocatalyst at the atomic scale to achieve highly selective electrocatalytic reactions.