Electroreduction of nitrate has been gaining wide attention in recent years owing to it's beneficial for converting nitrate into benign N_(2) from the perspective of electrocatalytic denitrification or into value-...Electroreduction of nitrate has been gaining wide attention in recent years owing to it's beneficial for converting nitrate into benign N_(2) from the perspective of electrocatalytic denitrification or into value-added ammonia from the perspective of electrocatalytic NH_(3) synthesis.By reason of the undesired formation of ammonia is dominant during electroreduction of nitrate-containing wastewater,chloride has been widely used to improve N_(2) selectivity.Nevertheless,selective electroreduction of nitrate to N2 gas in chloride-containing system poses several drawbacks.In this review,we focus on the key strategies for efficiently enhancing N_(2) selectivity of electroreduction of nitrate in chloride-free system,including optimal selection of elements,combining an active metal catalyst with another metal,manipulating the crystalline morphology and facet orientation,constructing core–shell structure catalysts,etc.Before summarizing the strategies,four possible reaction pathways of electro-reduction of nitrate to N_(2) are discussed.Overall,this review attempts to provide practical strategies for enhancing N2 selectivity without the aid of electrochlorination and highlight directions for future research for designing appropriate electrocatalyst for final electrocatalytic denitrifi-cation.展开更多
The d-d orbital coupling induced by crystal-phase engineering can effectively adjust the electronic structure of electrocatalysts,thus showing significant catalytic performance,while it has been rarely explored in ele...The d-d orbital coupling induced by crystal-phase engineering can effectively adjust the electronic structure of electrocatalysts,thus showing significant catalytic performance,while it has been rarely explored in electrochemical acetonitrile reduction reaction(ARR)to date.Herein,we successfully realize the structural transformation of Pd Cu metallic aerogels(MAs)from face-centered cubic(FCC)to body-centered cubic(BCC)through annealing treatment.Specifically,the BCC Pd Cu MAs exhibit excellent ARR performance with high ethylamine selectivity of 90.91%,Faradaic efficiency of 88.60%,yield rate of 316.0 mmol h^(-1)g^(-1)_(Pd+Cu)and long-term stability for consecutive electrolysis within 20 h at-0.55 V vs.reversible hydrogen electrode,outperforming than those of FCC Pd Cu MAs.Under the membrane electrode assembly system,BCC Pd Cu MAs also demonstrate excellent ethylamine yield rate of 389.5 mmol h^(-1)g^(-1)_(Pd+Cu).Density functional theory calculation reveals that the d-d orbital coupling in BCC Pd Cu MAs results in an evident correlation effect for the interaction of Pd and Cu sites,which boosts up the Cu sites electronic activities to enhance ARR performance.Our work opens a new route to develop efficient ARR electrocatalysts from the perspective of crystalline structure transformation.展开更多
Electrocatalytic converting CO_(2) into chemical products has emerged as a promising approach to achieving carbon neutrality.Herein,we report a bismuth-based catalyst with high curvature terminal and amorphous layer w...Electrocatalytic converting CO_(2) into chemical products has emerged as a promising approach to achieving carbon neutrality.Herein,we report a bismuth-based catalyst with high curvature terminal and amorphous layer which fabricated via two-step electrodeposition achieves stable formate output in a wide voltage window of 600 mV.The Faraday efficiency(FE) of formate reached up to 99.4% at-0.8 V vs.RHE and it remained constant for more than 92 h at-15 mA cm^(-2).More intriguingly,FE formate of95.4% can be realized at a current density of industrial grade(-667.7 mA cm^(-2)) in flow cell.The special structure promoted CO_(2) adsorption and reduced its activation energy and enhanced the electric-thermal field and K^(+) enrichment which accelerated the reaction kinetics.In situ spectroscopy and theoretical calculation further confirmed that the introduction of amorphous structure is beneficial to adsorpting CO_(2)and stabling*OCHO intermediate.This work provides special insights to fabricate efficient electrocatalysts by means of structural and crystal engineering and makes efforts to realize the industrialization of bismuth-based catalysts.展开更多
Electrochemical CO_(2)reduction to formate is a potential approach to achieving global carbon neutrality.Here,Cu1Bi1bimetallic catalyst was prepared by a co-precipitation method.It has a ginger like composite structur...Electrochemical CO_(2)reduction to formate is a potential approach to achieving global carbon neutrality.Here,Cu1Bi1bimetallic catalyst was prepared by a co-precipitation method.It has a ginger like composite structure(CuO/CuBi_(2)O_(4))and exhibited a high formate faradaic efficiency of 98.07%at–0.98 V and a large current density of–56.12 mA.cm^(-2)at–1.28 V,which is twice as high as Bi2O3catalyst.Especially,high selectivity(FE^(–)_(HCOO)>85%)is maintained over a wide potential window of 500 mV.In-situ Raman measurements and structure characterization revealed that the reduced Cu1Bi1bimetallic catalyst possesses abundant Cu-Bi interfaces and residual Bi-O structures.The abundant Cu-Bi interface structures on the catalyst surface can provide abundant active sites for CO_(2)RR,while the Bi-O structures may stabilize the CO_(2)^(*–)intermediate.The synergistic effect of abundant Cu-Bi interfaces and Bi-O species promotes the efficient synthesis of formate by following the OCHO^(*)pathway.展开更多
Earth-abundant and nontoxic Sn-based materials have been regarded as promising catalysts for the electrochemical conversion of CO_(2)to C1 products,e.g.,CO and formate.However,it is still difficult for Snbased materia...Earth-abundant and nontoxic Sn-based materials have been regarded as promising catalysts for the electrochemical conversion of CO_(2)to C1 products,e.g.,CO and formate.However,it is still difficult for Snbased materials to obtain satisfactory performance at low-to-moderate overpotentials.Herein,a simple and facile electrospinning technique is utilized to prepare a composite of a bimetallic Sn-Co oxide/carbon matrix with a hollow nanotube structure(Sn Co-HNT).Sn Co-HNT can maintain>90%faradaic efficiencies for C1 products within a wide potential range from-0.6 VRHE to-1.2 VRHE,and a highest 94.1%selectivity towards CO in an H-type cell.Moreover,a 91.2%faradaic efficiency with a 241.3 m A cm^(-2)partial current density for C1 products could be achieved using a flow cell.According to theoretical calculations,the fusing of Sn/Co oxides on the carbon matrix accelerates electron transfer at the atomic level,causing electron deficiency of Sn centers and reversible variation between Co^(2+)and Co^(3+)centers.The synergistic effect of the Sn/Co composition improves the electron affinity of the catalyst surface,which is conducive to the adsorption and stabilization of key intermediates and eventually increases the catalytic activity in CO_(2)electroreduction.This study could provide a new strategy for the construction of oxide-derived catalysts for CO_(2)electroreduction.展开更多
Electrochemical CO_(2)reduction(CO_(2)RR)over molecular catalysts is a paramount approach for CO_(2)conversion to CO.Herein,we report a novel phthalocyanine-derived catalyst synthesized by a two-step method with a muc...Electrochemical CO_(2)reduction(CO_(2)RR)over molecular catalysts is a paramount approach for CO_(2)conversion to CO.Herein,we report a novel phthalocyanine-derived catalyst synthesized by a two-step method with a much improved electroconductivity.Furthermore,the catalyst contains both Ni-N4sites and highly dispersed metallic Ni nanoclusters,leading to an increased CO_(2)RR currents by two folds.Isotope labelling study and in situ spectroscopic analysis demonstrate that the existence of metallic Ni nanoclusters is the key factor for the activity enhancement and can shift the CO_(2)RR mechanism from being electron transfer(ET)-limited(forming*COO^(-))to concerted proton-electron transfer(CPET)-limited(forming CO).展开更多
Electrochemical CO reduction reaction(CORR) provides a promising approach for producing valuable multicarbon products(C_(2+)), while the low solubility of CO in aqueous solution and high energy barrier of C–C couplin...Electrochemical CO reduction reaction(CORR) provides a promising approach for producing valuable multicarbon products(C_(2+)), while the low solubility of CO in aqueous solution and high energy barrier of C–C coupling as well as the competing hydrogen evolution reaction(HER) largely limit the efficiency for C_(2+)production in CORR. Here we report an overturn on the Faradaic efficiency of CORR from being HER-dominant to C_(2+)formation-dominant over a wide potential window, accompanied by a significant activity enhancement over a Moss-like Cu catalyst via pressuring CO. With the CO pressure rising from 1 to 40 atm, the C_(2+)Faradaic efficiency and partial current density remarkably increase from 22.8%and 18.9 mA cm^(-2)to 89.7% and 116.7 mA cm^(-2), respectively. Experimental and theoretical investigations reveal that high pressure-induced high CO coverage on metallic Cu surface weakens the Cu–C bond via reducing electron transfer from Cu to adsorbed CO and restrains hydrogen adsorption, which significantly facilitates the C–C coupling while suppressing HER on the predominant Cu(111) surface, thereby boosting the CO electroreduction to C_(2+)activity.展开更多
Simultaneously achieving high activity,selectivity and stability for electrochemical CO_(2)reduction reaction(CO_(2)RR)remains great challenges.Herein,a phosphorus-modified Sn/Sn Oxcore/shell(P-Sn/SnO_x)catalyst,deriv...Simultaneously achieving high activity,selectivity and stability for electrochemical CO_(2)reduction reaction(CO_(2)RR)remains great challenges.Herein,a phosphorus-modified Sn/Sn Oxcore/shell(P-Sn/SnO_x)catalyst,derived from in situ electrochemical reduction of an amorphous Sn(HPO_(4))_(2) pre-catalyst,exhibits high CO_(2)RR performance.The total Faradaic efficiency(FE)of C_(1) products is close to 100%in a broad potential range from-0.49 to-1.02 V vs.reversible hydrogen electrode,and a total current density of 315.0 m A cm^(-2)is achieved.Moreover,the P-Sn/SnO_(x) catalyst maintains a formate FE of~90%for 120 h.Density functional theory calculations suggest that the phosphorus-modified Sn/SnO_(x) core/shell structure effectively facilitates formate production by enhancing CO_(2)adsorption and improving free energy profile of formate formation.展开更多
Implant-associated infections caused by biomedical catheters severely threaten patients'health.The use of electrochemical control on NO release from benign nitrite equipped in the catheter can potentially resolve ...Implant-associated infections caused by biomedical catheters severely threaten patients'health.The use of electrochemical control on NO release from benign nitrite equipped in the catheter can potentially resolve this issue with excellent biocompatibility.Inspired by nitrite reductase,a Cu-BDC(BDC:benzene-1,4-dicarboxylic acid)catalyst with coordinated Cu(Ⅱ)sites was constructed as a heterogeneous electrocatalyst to control nitrite reduction to nitric oxide for catheter antibacteria.The combined results of in situ and ex situ tests unveil the key function of interconversion between Cu(Ⅱ)and Cu(Ⅰ)species in NO_(2)^(-)reduction to NO.After being incorporated into the actual catheter,the Cu-BDC catalyst exhibits high electrocatalytic activity toward NO_(2)^(-)reduction to NO and excellent antibacteria efficacy with a sterilizing rate of 99.9%,paving the way for the development of advanced metal-organic frameworks(MOFs)electrocatalysts for catheter antibacteria.展开更多
Ammonia plays an essential role in human production and life as a raw material for chemical fertilizers.The nitrate electroreduction to ammonia reaction(NO_(3)RR)has garnered attention due to its advantages over the H...Ammonia plays an essential role in human production and life as a raw material for chemical fertilizers.The nitrate electroreduction to ammonia reaction(NO_(3)RR)has garnered attention due to its advantages over the Haber-Bosch process and electrochemical nitrogen reduction reaction.Therefore,it represents a promising approach to safeguard the ecological environment by enabling the cycling of nitrogen species.This review begins by discussing the theoretical insights of the NO_(3)RR.It then summarizes recent advances in catalyst design and construction strategies,including alloying,structure engineering,surface engineering,and heterostructure engineering.Finally,the challenges and prospects in this field are presented.This review aims to guide for enhancing the efficiency of electrocatalysts in the NO_(3)RR,and offers insights for converting NO_(3)-to NH_(3).展开更多
Regulating the selectivity toward a target hydrocarbon product is still the focus of CO_(2)electroreduction.Here,we discover that the original surface Cu species in Cu gas-diffusion electrodes plays a more important r...Regulating the selectivity toward a target hydrocarbon product is still the focus of CO_(2)electroreduction.Here,we discover that the original surface Cu species in Cu gas-diffusion electrodes plays a more important role than the surface roughness,local pH,and facet in governing the selectivity toward C_(1)or C_(2)hydrocarbons.The selectivity toward C_(2)H_(4) progressively increases,while CH_(4) decreases steadily upon lowering the Cu oxidation species fraction.At a relatively low electrodeposition voltage of 1.5 V,the Cu gas-diffusion electrode with the highest Cu^(δ+)/Cu^(0)ratio favors the pathways of∗CO hydrogenation to form CH_(4) with maximum Faradaic efficiency of 65.4%and partial current density of 228 mA cm^(−2)at−0.83 V vs RHE.At 2.0 V,the Cu gas-diffusion electrode with the lowest Cu^(δ+)/Cu^(0)ratio prefers C-C coupling to form C_(2)+products with Faradaic efficiency topping 80.1%at−0.75 V vs RHE,where the Faradaic efficiency of C_(2)H_(4) accounts for 46.4%and the partial current density of C_(2)H_(4) achieves 279 mA cm^(−2).This work demonstrates that the selectivity from CH_(4) to C_(2)H_(4) is switchable by tuning surface Cu species composition of Cu gas-diffusion electrodes.展开更多
A simple method was proposed to activate alkaline Cu(OH)_(2)with an acidic ionomer,Nafion,to regulate its surface microenvironment,including hydrophobicity and local basicity.In particular,the direct complete neutrali...A simple method was proposed to activate alkaline Cu(OH)_(2)with an acidic ionomer,Nafion,to regulate its surface microenvironment,including hydrophobicity and local basicity.In particular,the direct complete neutralization reaction between Cu(OH)_(2)and Nafion in aqueous solution induces the exposing of vast anions which can exclude the in-situ-formed hydroxides and raise the local basicity.Remarkably,the optimal Nafionactivated Cu(OH)_(2)-derived Cu can efficiently suppress the hydrogen evolution reaction(HER)and improve the selectivity for multi-carbon products in the CO_(2)electroreduction reaction(eCO_(2)RR).The H2 Faradaic efficiency(FE)decreased to 11%at a current density of 300 mA/cm2(−0.76 V vs.RHE)in a flow cell,while the bare one with H2 had an FE of 40%.The total eCO_(2)RR FE reaches as high as 83%,along with an evidently increased C2H4 FE of 44%as compared with the bare one(24%),and good stability(8000 s),surpassing that of most of the reported Cu(OH)_(2)-derived Cu.The experimental and theoretical results both show that the strong hydrophobicity and high local basicity jointly boosted the eCO_(2)RR as acquired by felicitously introducing ionomer on the Cu(OH)_(2)-derived Cu surface.展开更多
CO_(2) electroreduction(CO_(2) ER)to high value-added chemicals is considered as a promising technology to achieve sustainable carbon neutralization.By virtue of the progressive research in recent years aiming at desi...CO_(2) electroreduction(CO_(2) ER)to high value-added chemicals is considered as a promising technology to achieve sustainable carbon neutralization.By virtue of the progressive research in recent years aiming at design and understanding of catalytic materials and electrolyte systems,the CO_(2) ER performance(such as current density,selectivity,stability,CO_(2) conversion,etc.)has been continually increased.Unfortunately,there has been relatively little attention paid to the large-scale CO 2 electrolyzers,which stand just as one obstacle,alongside series-parallel integration,challenging the practical application of this infant technology.In this review,the latest progress on the structures of low-temperature CO_(2) electrolyzers and scale-up studies was systematically overviewed.The influence of the CO_(2) electrolyzer configurations,such as the flow channel design,gas diffusion electrode(GDE)and ion exchange membrane(IEM),on the CO_(2) ER performance was further discussed.The review could provide inspiration for the design of large-scale CO_(2) electrolyzers so as to accelerate the industrial application of CO_(2) ER technology.展开更多
Capturing CO_(2) from the atmosphere and converting it into fuels are an effi cient strategy to stop the deteriorating greenhouse eff ect and alleviate the energy crisis.Among various CO_(2) conversion approaches,elec...Capturing CO_(2) from the atmosphere and converting it into fuels are an effi cient strategy to stop the deteriorating greenhouse eff ect and alleviate the energy crisis.Among various CO_(2) conversion approaches,electrocatalytic CO_(2) reduction reaction(CO_(2) RR)has received extensive attention because of its mild operating conditions.However,the high onset potential,low selectivity toward multi-carbon products and poor cruising ability of CO_(2) RR impede its development.To regulate product distribution,previous studies performed electrocatalyst modifi cation using several universal methods,including composition manipulation,morphology control,surface modifi cation,and defect engineering.Recent studies have revealed that the cathode and electrolytes infl uence the selectivity of CO_(2) RR via pH changes and ionic eff ects,or by directly participating in the reduction pathway as cocatalysts.This review summarizes the state-of-the-art optimization strategies to effi ciently enhance CO_(2) RR selectivity from two main aspects,namely the cathode electrocatalyst and the electrolyte.展开更多
It is well-known that the electrolytes can influence the electrochemical reduction of carbon dioxide(ERCO2)in aqueous media.In this work,we explore the effects of alkali metal cations and anions(Li^+,Na^+,K^+,Rb^+,Cs^...It is well-known that the electrolytes can influence the electrochemical reduction of carbon dioxide(ERCO2)in aqueous media.In this work,we explore the effects of alkali metal cations and anions(Li^+,Na^+,K^+,Rb^+,Cs^+,HCO3^-,Cl^-,Br^-,I^-)on the current density and product selectivity for the ERCO2 into formic acid(HCOOH)on the SnO2/carbon paper(Sn O2/C)electrode.Results of the ERCO2 experiments show that for the cations,the promotion effects on current density and faradaic efficiencies(FEs)are in the order of Li^+b Na^+b K^+b Cs^+b Rb^+.For the anions,the current density values are in the order of Na HCO3 b NaClb Na Br b Na I and KHCO3 b KCl≈KI b KBr,respectively,and that on the FEs for the formation of the HCOOH(FEHCOOH)is HCO3-b Cl-b Br-b I-.Based on this result,the effects of alkali metal cations and anions on ERCO2 are discussed.展开更多
Developing of economic and efficient catalysts is critical for the application of electroreduction of carbon dioxide to highly valuable chemicals.Herein,we present a facile method to synthesize N-doped hieratically po...Developing of economic and efficient catalysts is critical for the application of electroreduction of carbon dioxide to highly valuable chemicals.Herein,we present a facile method to synthesize N-doped hieratically porous carbon through pyrolysis of petroleum pitch followed by ammonia etching.We found mesopores are favored formation by removing of asphaltene from petroleum pitch during the carbonation process.Simultaneously,ammonia etching can not only increase the pyridinic-N content,but also upgrade the ratio of meso-to micro-pores of carbon materials.Using the N-doped hieratically porous carbon as catalyst for carbon dioxide electroreduction,the Faradaic efficiency of carbon monoxide reaches 83%at-0.9 V vs.the reversible hydrogen electrode(RHE)in 0.1 M KHCO_(3).This superior performance is attributed to the synergistic effects of highly pyridinic-N content in conjunction with the hieratically porous architecture,rendering abundant exposed and accessible active sites for electroreduction of CO_(2).Our work provides a new strategy for the large-scale preparation of high-performance,low-cost catalysts for CO_(2) electroreduction.展开更多
Surface chemistry modification represents a promising strategy to tailor the adsorption and activation of reaction intermediates for enhancing activity.Herein,we designed a surface oxygen-injection strategy to tune th...Surface chemistry modification represents a promising strategy to tailor the adsorption and activation of reaction intermediates for enhancing activity.Herein,we designed a surface oxygen-injection strategy to tune the electronic structure of SnS_(2) nanosheets,which showed effectively enhanced electrocatalytic activity and selectivity of CO_(2) reduction to formate and syngas(CO and H_(2)).The oxygen-injection SnS_(2) nanosheets exhibit a remarkable Faradaic efficiency of 91.6%for carbonaceous products with a current density of 24.1 mA cm^(−2) at−0.9 V vs RHE,including 83.2%for formate production and 16.5%for syngas with the CO/H_(2) ratio of 1:1.By operando X-ray absorption spectroscopy,we unravel the in situ surface oxygen doping into the matrix during reaction,thereby optimizing the Sn local electronic states.Operando synchrotron radiation infrared spectroscopy along with theoretical calculations further reveals that the surface oxygen doping facilitated the CO_(2) activation and enhanced the affinity for HCOO*species.This result demonstrates the potential strategy of surface oxygen injection for the rational design of advanced catalysts for CO_(2) electroreduction.展开更多
Atomically dispersed metal-nitrogen sites-anchored carbon materials have been developed as effective catalysts for CO2 electroreduction(CO2 ER),but they still suffer from the imprecisely control of type and coordinati...Atomically dispersed metal-nitrogen sites-anchored carbon materials have been developed as effective catalysts for CO2 electroreduction(CO2 ER),but they still suffer from the imprecisely control of type and coordination number of N atoms bonded with central metal.Herein,we develop a family of single metal atom bonded by N atoms anchored on carbons(SAs-M-N-C,M=Fe,Co,Ni,Cu)for CO2 ER,which composed of accurate pyrrole-type M-N4 structures with isolated metal atom coordinated by four pyrrolic N atoms.Benefitting from atomically coordinated environment and specific selectivity of M-N4 centers,SAs-Ni-N-C exhibits superior CO2 ER performance with onset potential of-0.3 V,CO Faradaic efficiency(F.E.) of 98.5%at-0.7 V,along with low Tafel slope of 115 mV dec-1 and superior stability of 50 h,exceeding all the previously reported M-N-C electrocatalysts for CO2-to-CO conversion.Experimental results manifest that the different intrinsic activities of M-N4 structures in SAs-M-N-C result in the corresponding sequence of Ni> Fe> Cu> Co for CO2 ER performance.An integrated Zn-CO2 battery with Zn foil and SAs-Ni-N-C is constructed to simultaneously achieve CO2-to-CO conversion and electric energy output,which delivers a peak power density of 1.4 mW cm-2 and maximum CO F.E.of 93.3%.展开更多
Perovskite oxides are popular as cathode materials of solid oxide electrolysis cells, because of their good redox stability and high resistance to coke formation.Unexpectedly, a negative effect of Ni doping is found o...Perovskite oxides are popular as cathode materials of solid oxide electrolysis cells, because of their good redox stability and high resistance to coke formation.Unexpectedly, a negative effect of Ni doping is found on Sr2Fe(1.5-x)NixMo(0.5)O(x = 0, 0.05, 0.1, 0.2) cathode for pure CO2 electroreduction at 800 ℃, although Ni is highly active for CO2 electroreduction.The CO2 electroreduction performance degrades with the increase of Ni doping amount.Various characterization techniques are used to disclose the negative effect.Ni doping decreases the perovskite stability under electroreduction conditions, Fe and Ni cations in the B-site are reduced to metal nanoparticles and SrCO3 forms on the surface of the perovskite.The phase instability results from the weaker Ni–O bond.Although the Fe-Ni nanoparticles are in favor of the CO2 electroreduction, too much SrCO3 and carbon deposition block the charge transfer and diffusion of oxygenous species on the cathode surface.展开更多
Herein we report CO_(2) electrochemical reduction reaction(CO_(2) ERR)on the cobalt tetraphenylporphyrin(Co TPP)modified TiO_(2) nanotube(TNT)electrode.It was found the axial coordination of drop-casting solvent to Co...Herein we report CO_(2) electrochemical reduction reaction(CO_(2) ERR)on the cobalt tetraphenylporphyrin(Co TPP)modified TiO_(2) nanotube(TNT)electrode.It was found the axial coordination of drop-casting solvent to Co TPP and the porphyrin structure are the major factors that have significant effects on the catalytic performance of the electrode.As confirmed by spectrophotometric titration,pyridine has a stronger coordination bond to Co TPP than DMF and THF thus leading to the highest efficiency among the dropcasting solvents tested in the study.Based on the spectrophotometric analysis,possible coordination mechanism between drop-casting solvents and Co TPP is put forward.On the other hand,introduction of-COOMe substituents in phenyl rings of Co TPP weakens the coordination bond between pyridine and Co TPP as clearly evidenced by deuterium NMR spectra,resulting in a detrimental effect on CO_(2) ERR.Therefore,the manipulation of the coordination environment around the metal center of immobilized catalyst is crucial in designing an efficient electrocatalytic system.展开更多
基金supported by State Key Laboratory of Water Resource Protection and Utilization in Coal Mining(No.GJNY-18-73.17).
文摘Electroreduction of nitrate has been gaining wide attention in recent years owing to it's beneficial for converting nitrate into benign N_(2) from the perspective of electrocatalytic denitrification or into value-added ammonia from the perspective of electrocatalytic NH_(3) synthesis.By reason of the undesired formation of ammonia is dominant during electroreduction of nitrate-containing wastewater,chloride has been widely used to improve N_(2) selectivity.Nevertheless,selective electroreduction of nitrate to N2 gas in chloride-containing system poses several drawbacks.In this review,we focus on the key strategies for efficiently enhancing N_(2) selectivity of electroreduction of nitrate in chloride-free system,including optimal selection of elements,combining an active metal catalyst with another metal,manipulating the crystalline morphology and facet orientation,constructing core–shell structure catalysts,etc.Before summarizing the strategies,four possible reaction pathways of electro-reduction of nitrate to N_(2) are discussed.Overall,this review attempts to provide practical strategies for enhancing N2 selectivity without the aid of electrochlorination and highlight directions for future research for designing appropriate electrocatalyst for final electrocatalytic denitrifi-cation.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52161135302,22105087)the Postdoctoral Research Foundation of China(Grant No.2022M721360)the Natural Science Foundation of Jiangsu Province(Grant No.BK20210446)。
文摘The d-d orbital coupling induced by crystal-phase engineering can effectively adjust the electronic structure of electrocatalysts,thus showing significant catalytic performance,while it has been rarely explored in electrochemical acetonitrile reduction reaction(ARR)to date.Herein,we successfully realize the structural transformation of Pd Cu metallic aerogels(MAs)from face-centered cubic(FCC)to body-centered cubic(BCC)through annealing treatment.Specifically,the BCC Pd Cu MAs exhibit excellent ARR performance with high ethylamine selectivity of 90.91%,Faradaic efficiency of 88.60%,yield rate of 316.0 mmol h^(-1)g^(-1)_(Pd+Cu)and long-term stability for consecutive electrolysis within 20 h at-0.55 V vs.reversible hydrogen electrode,outperforming than those of FCC Pd Cu MAs.Under the membrane electrode assembly system,BCC Pd Cu MAs also demonstrate excellent ethylamine yield rate of 389.5 mmol h^(-1)g^(-1)_(Pd+Cu).Density functional theory calculation reveals that the d-d orbital coupling in BCC Pd Cu MAs results in an evident correlation effect for the interaction of Pd and Cu sites,which boosts up the Cu sites electronic activities to enhance ARR performance.Our work opens a new route to develop efficient ARR electrocatalysts from the perspective of crystalline structure transformation.
基金financial support from the Zhejiang Provincial Natural Science Foundation of China(LQ22B060007)the National Natural Science Foundation of China(22206042)+2 种基金the Scientific Research Start-up of Hangzhou Normal University(2021GDL014)the Hebei Natural Science Foundation(E2021203047)the Hebei Provincial Foundation for Returness(C20200369)。
文摘Electrocatalytic converting CO_(2) into chemical products has emerged as a promising approach to achieving carbon neutrality.Herein,we report a bismuth-based catalyst with high curvature terminal and amorphous layer which fabricated via two-step electrodeposition achieves stable formate output in a wide voltage window of 600 mV.The Faraday efficiency(FE) of formate reached up to 99.4% at-0.8 V vs.RHE and it remained constant for more than 92 h at-15 mA cm^(-2).More intriguingly,FE formate of95.4% can be realized at a current density of industrial grade(-667.7 mA cm^(-2)) in flow cell.The special structure promoted CO_(2) adsorption and reduced its activation energy and enhanced the electric-thermal field and K^(+) enrichment which accelerated the reaction kinetics.In situ spectroscopy and theoretical calculation further confirmed that the introduction of amorphous structure is beneficial to adsorpting CO_(2)and stabling*OCHO intermediate.This work provides special insights to fabricate efficient electrocatalysts by means of structural and crystal engineering and makes efforts to realize the industrialization of bismuth-based catalysts.
基金financially supported by the National Natural Science Foundation of China(22172082,21978137,and 21878162)the Natural Science Foundation of Tianjin(20JCZDJC00770)+1 种基金the NCC Fund(NCC2020FH05)the Fundamental Research Funds for the Central Universities。
文摘Electrochemical CO_(2)reduction to formate is a potential approach to achieving global carbon neutrality.Here,Cu1Bi1bimetallic catalyst was prepared by a co-precipitation method.It has a ginger like composite structure(CuO/CuBi_(2)O_(4))and exhibited a high formate faradaic efficiency of 98.07%at–0.98 V and a large current density of–56.12 mA.cm^(-2)at–1.28 V,which is twice as high as Bi2O3catalyst.Especially,high selectivity(FE^(–)_(HCOO)>85%)is maintained over a wide potential window of 500 mV.In-situ Raman measurements and structure characterization revealed that the reduced Cu1Bi1bimetallic catalyst possesses abundant Cu-Bi interfaces and residual Bi-O structures.The abundant Cu-Bi interface structures on the catalyst surface can provide abundant active sites for CO_(2)RR,while the Bi-O structures may stabilize the CO_(2)^(*–)intermediate.The synergistic effect of abundant Cu-Bi interfaces and Bi-O species promotes the efficient synthesis of formate by following the OCHO^(*)pathway.
基金supported by the National Natural Science Foundation of China(U21A20312,22172099,21975162,51902209)the Natural Science Foundation of Guangdong(2020A1515010840)the Shenzhen Science and Technology Program(SGDX20201103095802006,RCBS20200714114819161,JCYJ20190808111801674,JCYJ20200109105803806,RCYX20200714114535052)。
文摘Earth-abundant and nontoxic Sn-based materials have been regarded as promising catalysts for the electrochemical conversion of CO_(2)to C1 products,e.g.,CO and formate.However,it is still difficult for Snbased materials to obtain satisfactory performance at low-to-moderate overpotentials.Herein,a simple and facile electrospinning technique is utilized to prepare a composite of a bimetallic Sn-Co oxide/carbon matrix with a hollow nanotube structure(Sn Co-HNT).Sn Co-HNT can maintain>90%faradaic efficiencies for C1 products within a wide potential range from-0.6 VRHE to-1.2 VRHE,and a highest 94.1%selectivity towards CO in an H-type cell.Moreover,a 91.2%faradaic efficiency with a 241.3 m A cm^(-2)partial current density for C1 products could be achieved using a flow cell.According to theoretical calculations,the fusing of Sn/Co oxides on the carbon matrix accelerates electron transfer at the atomic level,causing electron deficiency of Sn centers and reversible variation between Co^(2+)and Co^(3+)centers.The synergistic effect of the Sn/Co composition improves the electron affinity of the catalyst surface,which is conducive to the adsorption and stabilization of key intermediates and eventually increases the catalytic activity in CO_(2)electroreduction.This study could provide a new strategy for the construction of oxide-derived catalysts for CO_(2)electroreduction.
基金sponsored by the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning and Shanghai Sailing Program(19YF1410600)。
文摘Electrochemical CO_(2)reduction(CO_(2)RR)over molecular catalysts is a paramount approach for CO_(2)conversion to CO.Herein,we report a novel phthalocyanine-derived catalyst synthesized by a two-step method with a much improved electroconductivity.Furthermore,the catalyst contains both Ni-N4sites and highly dispersed metallic Ni nanoclusters,leading to an increased CO_(2)RR currents by two folds.Isotope labelling study and in situ spectroscopic analysis demonstrate that the existence of metallic Ni nanoclusters is the key factor for the activity enhancement and can shift the CO_(2)RR mechanism from being electron transfer(ET)-limited(forming*COO^(-))to concerted proton-electron transfer(CPET)-limited(forming CO).
基金financial support from the National Key R&D Program of China (Nos. 2022YFA1504500, 2022YFA1503100)the National Natural Science Foundation of China (Nos. 21988101, 21890753, 22225204, 92145301, 22002160 and 22272174)+4 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB36030200)the CAS Project for Young Scientists in Basic Research (No. YSBR-028)the Fundamental Research Funds for the Central Universities (No. 20720220008)the Dalian National Lab for Clean Energy (DNL Cooperation Fund 202001)the Innovation Research Fund Project of DICP (No. DICP I202016)。
文摘Electrochemical CO reduction reaction(CORR) provides a promising approach for producing valuable multicarbon products(C_(2+)), while the low solubility of CO in aqueous solution and high energy barrier of C–C coupling as well as the competing hydrogen evolution reaction(HER) largely limit the efficiency for C_(2+)production in CORR. Here we report an overturn on the Faradaic efficiency of CORR from being HER-dominant to C_(2+)formation-dominant over a wide potential window, accompanied by a significant activity enhancement over a Moss-like Cu catalyst via pressuring CO. With the CO pressure rising from 1 to 40 atm, the C_(2+)Faradaic efficiency and partial current density remarkably increase from 22.8%and 18.9 mA cm^(-2)to 89.7% and 116.7 mA cm^(-2), respectively. Experimental and theoretical investigations reveal that high pressure-induced high CO coverage on metallic Cu surface weakens the Cu–C bond via reducing electron transfer from Cu to adsorbed CO and restrains hydrogen adsorption, which significantly facilitates the C–C coupling while suppressing HER on the predominant Cu(111) surface, thereby boosting the CO electroreduction to C_(2+)activity.
基金supported by the National Key R&D Program of China (2021YFA1501503)the National Natural Science Foundation of China (22125205,22002155,22002158,92045302)+5 种基金the“Transformational Technologies for Clean Energy and Demonstration”Strategic Priority Research Program of the Chinese Academy of Sciences (XDA21070613)the Fundamental Research Funds for the Central Universities (20720220008)the China Postdoctoral Science Foundation (2019M661142)the Natural Science Foundation of Liaoning Province (2021-MS-022)the High-Level Talents Innovation Project of Dalian City (2020RQ038)the support from the Photon Science Center for Carbon Neutrality。
文摘Simultaneously achieving high activity,selectivity and stability for electrochemical CO_(2)reduction reaction(CO_(2)RR)remains great challenges.Herein,a phosphorus-modified Sn/Sn Oxcore/shell(P-Sn/SnO_x)catalyst,derived from in situ electrochemical reduction of an amorphous Sn(HPO_(4))_(2) pre-catalyst,exhibits high CO_(2)RR performance.The total Faradaic efficiency(FE)of C_(1) products is close to 100%in a broad potential range from-0.49 to-1.02 V vs.reversible hydrogen electrode,and a total current density of 315.0 m A cm^(-2)is achieved.Moreover,the P-Sn/SnO_(x) catalyst maintains a formate FE of~90%for 120 h.Density functional theory calculations suggest that the phosphorus-modified Sn/SnO_(x) core/shell structure effectively facilitates formate production by enhancing CO_(2)adsorption and improving free energy profile of formate formation.
基金the financial support from National Postdoctoral Science Foundation of China(Nos.2021M702436 and BX2021211)Haihe Laboratory of Sustainable Chemical Transformations+1 种基金National Natural Science Foundation of China(Nos.22101202 and 22071173)Tianjin Science and Technology Programme(Nos.20JCJQJC00050 and 22ZYJDSS00060)。
文摘Implant-associated infections caused by biomedical catheters severely threaten patients'health.The use of electrochemical control on NO release from benign nitrite equipped in the catheter can potentially resolve this issue with excellent biocompatibility.Inspired by nitrite reductase,a Cu-BDC(BDC:benzene-1,4-dicarboxylic acid)catalyst with coordinated Cu(Ⅱ)sites was constructed as a heterogeneous electrocatalyst to control nitrite reduction to nitric oxide for catheter antibacteria.The combined results of in situ and ex situ tests unveil the key function of interconversion between Cu(Ⅱ)and Cu(Ⅰ)species in NO_(2)^(-)reduction to NO.After being incorporated into the actual catheter,the Cu-BDC catalyst exhibits high electrocatalytic activity toward NO_(2)^(-)reduction to NO and excellent antibacteria efficacy with a sterilizing rate of 99.9%,paving the way for the development of advanced metal-organic frameworks(MOFs)electrocatalysts for catheter antibacteria.
基金supported by the National Natural Science Foundation of China(22202151)Fundamental Research Program of Shanxi Province(202203021212243)。
文摘Ammonia plays an essential role in human production and life as a raw material for chemical fertilizers.The nitrate electroreduction to ammonia reaction(NO_(3)RR)has garnered attention due to its advantages over the Haber-Bosch process and electrochemical nitrogen reduction reaction.Therefore,it represents a promising approach to safeguard the ecological environment by enabling the cycling of nitrogen species.This review begins by discussing the theoretical insights of the NO_(3)RR.It then summarizes recent advances in catalyst design and construction strategies,including alloying,structure engineering,surface engineering,and heterostructure engineering.Finally,the challenges and prospects in this field are presented.This review aims to guide for enhancing the efficiency of electrocatalysts in the NO_(3)RR,and offers insights for converting NO_(3)-to NH_(3).
基金partially financially supported by NSF CBET-2033343.J.Z.thanks the support from National Natural Science Foundation of China(52172293,51772072,and 51672065)the Fundamental Research Funds for the Central Universities(JZ2021HGQB0282 and PA2021GDSK0088)+3 种基金financial support from the Key R&D Projects of Anhui Province(202104b11020016)the 111 Project(B18018)the National Synchrotron Light Source II,a U.S.Department of Energy(DOE)Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No.DE-SC0012704the use of facilities within the Eyring Materials Center at Arizona State University supported in part by NNCI-ECCS-1542160.
文摘Regulating the selectivity toward a target hydrocarbon product is still the focus of CO_(2)electroreduction.Here,we discover that the original surface Cu species in Cu gas-diffusion electrodes plays a more important role than the surface roughness,local pH,and facet in governing the selectivity toward C_(1)or C_(2)hydrocarbons.The selectivity toward C_(2)H_(4) progressively increases,while CH_(4) decreases steadily upon lowering the Cu oxidation species fraction.At a relatively low electrodeposition voltage of 1.5 V,the Cu gas-diffusion electrode with the highest Cu^(δ+)/Cu^(0)ratio favors the pathways of∗CO hydrogenation to form CH_(4) with maximum Faradaic efficiency of 65.4%and partial current density of 228 mA cm^(−2)at−0.83 V vs RHE.At 2.0 V,the Cu gas-diffusion electrode with the lowest Cu^(δ+)/Cu^(0)ratio prefers C-C coupling to form C_(2)+products with Faradaic efficiency topping 80.1%at−0.75 V vs RHE,where the Faradaic efficiency of C_(2)H_(4) accounts for 46.4%and the partial current density of C_(2)H_(4) achieves 279 mA cm^(−2).This work demonstrates that the selectivity from CH_(4) to C_(2)H_(4) is switchable by tuning surface Cu species composition of Cu gas-diffusion electrodes.
基金National Natural Science Foundation of China,Grant/Award Numbers:52201227,21972126,51872209,52072273Zhejiang Provincial Special Support Program for High-level Talents,Grant/Award Number:2019R52042Key Project of Zhejiang Provincial Natural Science Foundation,Grant/Award Number:LZ20B030001。
文摘A simple method was proposed to activate alkaline Cu(OH)_(2)with an acidic ionomer,Nafion,to regulate its surface microenvironment,including hydrophobicity and local basicity.In particular,the direct complete neutralization reaction between Cu(OH)_(2)and Nafion in aqueous solution induces the exposing of vast anions which can exclude the in-situ-formed hydroxides and raise the local basicity.Remarkably,the optimal Nafionactivated Cu(OH)_(2)-derived Cu can efficiently suppress the hydrogen evolution reaction(HER)and improve the selectivity for multi-carbon products in the CO_(2)electroreduction reaction(eCO_(2)RR).The H2 Faradaic efficiency(FE)decreased to 11%at a current density of 300 mA/cm2(−0.76 V vs.RHE)in a flow cell,while the bare one with H2 had an FE of 40%.The total eCO_(2)RR FE reaches as high as 83%,along with an evidently increased C2H4 FE of 44%as compared with the bare one(24%),and good stability(8000 s),surpassing that of most of the reported Cu(OH)_(2)-derived Cu.The experimental and theoretical results both show that the strong hydrophobicity and high local basicity jointly boosted the eCO_(2)RR as acquired by felicitously introducing ionomer on the Cu(OH)_(2)-derived Cu surface.
基金supported by National Key R&D Program of China(2020YFA0710200)the National Natural Science Foundation of China(21838010,22122814)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2018064)State Key Laboratory of Multiphase complex systems,Institute of Process Engineering,Chinese Academy of Sciences(No.MPCS-2022-A-03)Innovation Academy for Green Manufacture Institute,Chinese Academy of Science(IAGM2020C14).
文摘CO_(2) electroreduction(CO_(2) ER)to high value-added chemicals is considered as a promising technology to achieve sustainable carbon neutralization.By virtue of the progressive research in recent years aiming at design and understanding of catalytic materials and electrolyte systems,the CO_(2) ER performance(such as current density,selectivity,stability,CO_(2) conversion,etc.)has been continually increased.Unfortunately,there has been relatively little attention paid to the large-scale CO 2 electrolyzers,which stand just as one obstacle,alongside series-parallel integration,challenging the practical application of this infant technology.In this review,the latest progress on the structures of low-temperature CO_(2) electrolyzers and scale-up studies was systematically overviewed.The influence of the CO_(2) electrolyzer configurations,such as the flow channel design,gas diffusion electrode(GDE)and ion exchange membrane(IEM),on the CO_(2) ER performance was further discussed.The review could provide inspiration for the design of large-scale CO_(2) electrolyzers so as to accelerate the industrial application of CO_(2) ER technology.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.22071173,21871206)the Natural Science Foundation of Tianjin City(No.17JCJQJC44700).
文摘Capturing CO_(2) from the atmosphere and converting it into fuels are an effi cient strategy to stop the deteriorating greenhouse eff ect and alleviate the energy crisis.Among various CO_(2) conversion approaches,electrocatalytic CO_(2) reduction reaction(CO_(2) RR)has received extensive attention because of its mild operating conditions.However,the high onset potential,low selectivity toward multi-carbon products and poor cruising ability of CO_(2) RR impede its development.To regulate product distribution,previous studies performed electrocatalyst modifi cation using several universal methods,including composition manipulation,morphology control,surface modifi cation,and defect engineering.Recent studies have revealed that the cathode and electrolytes infl uence the selectivity of CO_(2) RR via pH changes and ionic eff ects,or by directly participating in the reduction pathway as cocatalysts.This review summarizes the state-of-the-art optimization strategies to effi ciently enhance CO_(2) RR selectivity from two main aspects,namely the cathode electrocatalyst and the electrolyte.
基金financially supported by International Academic Cooperation and Exchange Program of Shanghai Science and Technology Committee(18160723600)Scientific Research and Technology Development Plan of Guangxi(GUIKE AD17195084)。
文摘It is well-known that the electrolytes can influence the electrochemical reduction of carbon dioxide(ERCO2)in aqueous media.In this work,we explore the effects of alkali metal cations and anions(Li^+,Na^+,K^+,Rb^+,Cs^+,HCO3^-,Cl^-,Br^-,I^-)on the current density and product selectivity for the ERCO2 into formic acid(HCOOH)on the SnO2/carbon paper(Sn O2/C)electrode.Results of the ERCO2 experiments show that for the cations,the promotion effects on current density and faradaic efficiencies(FEs)are in the order of Li^+b Na^+b K^+b Cs^+b Rb^+.For the anions,the current density values are in the order of Na HCO3 b NaClb Na Br b Na I and KHCO3 b KCl≈KI b KBr,respectively,and that on the FEs for the formation of the HCOOH(FEHCOOH)is HCO3-b Cl-b Br-b I-.Based on this result,the effects of alkali metal cations and anions on ERCO2 are discussed.
基金financially supported by the National Natural Science Foundation of China(21808242)the Shandong Provincial Natural Science Foundation(ZR2018BB070)+1 种基金the Fundamental Research Funds for the Central Universities of China(19CX02042A)the Foundation of State Key Laboratory of Highefficiency Utilization of Coal and Green Chemical Engineering(2020-KF-31)。
文摘Developing of economic and efficient catalysts is critical for the application of electroreduction of carbon dioxide to highly valuable chemicals.Herein,we present a facile method to synthesize N-doped hieratically porous carbon through pyrolysis of petroleum pitch followed by ammonia etching.We found mesopores are favored formation by removing of asphaltene from petroleum pitch during the carbonation process.Simultaneously,ammonia etching can not only increase the pyridinic-N content,but also upgrade the ratio of meso-to micro-pores of carbon materials.Using the N-doped hieratically porous carbon as catalyst for carbon dioxide electroreduction,the Faradaic efficiency of carbon monoxide reaches 83%at-0.9 V vs.the reversible hydrogen electrode(RHE)in 0.1 M KHCO_(3).This superior performance is attributed to the synergistic effects of highly pyridinic-N content in conjunction with the hieratically porous architecture,rendering abundant exposed and accessible active sites for electroreduction of CO_(2).Our work provides a new strategy for the large-scale preparation of high-performance,low-cost catalysts for CO_(2) electroreduction.
基金This work was supported by National Natural Science Foundation of China(Grants No.12025505)China Ministry of Science and Technology(2017YFA0208300)+2 种基金Youth Innovation Promotion Association CAS(CX2310007007 and CX2310000091)Open Fund Project of State Key Laboratory of Environmentally Friendly Energy Materials(20kfhg08)We would thank NSRL and SSRF for the synchrotron beam time.The calculations were performed on the supercomputing system in the Supercomputing Center of University of Science and Technology of China.
文摘Surface chemistry modification represents a promising strategy to tailor the adsorption and activation of reaction intermediates for enhancing activity.Herein,we designed a surface oxygen-injection strategy to tune the electronic structure of SnS_(2) nanosheets,which showed effectively enhanced electrocatalytic activity and selectivity of CO_(2) reduction to formate and syngas(CO and H_(2)).The oxygen-injection SnS_(2) nanosheets exhibit a remarkable Faradaic efficiency of 91.6%for carbonaceous products with a current density of 24.1 mA cm^(−2) at−0.9 V vs RHE,including 83.2%for formate production and 16.5%for syngas with the CO/H_(2) ratio of 1:1.By operando X-ray absorption spectroscopy,we unravel the in situ surface oxygen doping into the matrix during reaction,thereby optimizing the Sn local electronic states.Operando synchrotron radiation infrared spectroscopy along with theoretical calculations further reveals that the surface oxygen doping facilitated the CO_(2) activation and enhanced the affinity for HCOO*species.This result demonstrates the potential strategy of surface oxygen injection for the rational design of advanced catalysts for CO_(2) electroreduction.
基金financial support from Zhejiang Province Basic Public Welfare Research Project(LGF19B070006)financial supports from National Natural Science Foundation of China(21922811,21878270,51702284,21961160742)+2 种基金Zhejiang Provincial Natural Science Foundation of China(LR19B060002)supported by the Fundamental Research Funds for the Central Universitiesthe Startup Foundation for Hundred-Talent Program of Zhejiang University.
文摘Atomically dispersed metal-nitrogen sites-anchored carbon materials have been developed as effective catalysts for CO2 electroreduction(CO2 ER),but they still suffer from the imprecisely control of type and coordination number of N atoms bonded with central metal.Herein,we develop a family of single metal atom bonded by N atoms anchored on carbons(SAs-M-N-C,M=Fe,Co,Ni,Cu)for CO2 ER,which composed of accurate pyrrole-type M-N4 structures with isolated metal atom coordinated by four pyrrolic N atoms.Benefitting from atomically coordinated environment and specific selectivity of M-N4 centers,SAs-Ni-N-C exhibits superior CO2 ER performance with onset potential of-0.3 V,CO Faradaic efficiency(F.E.) of 98.5%at-0.7 V,along with low Tafel slope of 115 mV dec-1 and superior stability of 50 h,exceeding all the previously reported M-N-C electrocatalysts for CO2-to-CO conversion.Experimental results manifest that the different intrinsic activities of M-N4 structures in SAs-M-N-C result in the corresponding sequence of Ni> Fe> Cu> Co for CO2 ER performance.An integrated Zn-CO2 battery with Zn foil and SAs-Ni-N-C is constructed to simultaneously achieve CO2-to-CO conversion and electric energy output,which delivers a peak power density of 1.4 mW cm-2 and maximum CO F.E.of 93.3%.
基金the financial support from the National Natural Science Foundation of China (91545202, U1508203)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDB17000000)+2 种基金Dalian National Laboratory for Clean Energy (DNL)CAS (DICP&QIBEBT UN201708)Dalian Youth Science and Technology Fund (2017RQ064)
文摘Perovskite oxides are popular as cathode materials of solid oxide electrolysis cells, because of their good redox stability and high resistance to coke formation.Unexpectedly, a negative effect of Ni doping is found on Sr2Fe(1.5-x)NixMo(0.5)O(x = 0, 0.05, 0.1, 0.2) cathode for pure CO2 electroreduction at 800 ℃, although Ni is highly active for CO2 electroreduction.The CO2 electroreduction performance degrades with the increase of Ni doping amount.Various characterization techniques are used to disclose the negative effect.Ni doping decreases the perovskite stability under electroreduction conditions, Fe and Ni cations in the B-site are reduced to metal nanoparticles and SrCO3 forms on the surface of the perovskite.The phase instability results from the weaker Ni–O bond.Although the Fe-Ni nanoparticles are in favor of the CO2 electroreduction, too much SrCO3 and carbon deposition block the charge transfer and diffusion of oxygenous species on the cathode surface.
基金Financial support from the ARC Discovery Project(DP1901013720)。
文摘Herein we report CO_(2) electrochemical reduction reaction(CO_(2) ERR)on the cobalt tetraphenylporphyrin(Co TPP)modified TiO_(2) nanotube(TNT)electrode.It was found the axial coordination of drop-casting solvent to Co TPP and the porphyrin structure are the major factors that have significant effects on the catalytic performance of the electrode.As confirmed by spectrophotometric titration,pyridine has a stronger coordination bond to Co TPP than DMF and THF thus leading to the highest efficiency among the dropcasting solvents tested in the study.Based on the spectrophotometric analysis,possible coordination mechanism between drop-casting solvents and Co TPP is put forward.On the other hand,introduction of-COOMe substituents in phenyl rings of Co TPP weakens the coordination bond between pyridine and Co TPP as clearly evidenced by deuterium NMR spectra,resulting in a detrimental effect on CO_(2) ERR.Therefore,the manipulation of the coordination environment around the metal center of immobilized catalyst is crucial in designing an efficient electrocatalytic system.