In this paper, a low-cost activated carbon(AC) was prepared from deactivated resin catalyst(DRC) for methyl tert-butyl ether(MTBE) synthesis through carbonization and subsequent steam activation treatment. The activat...In this paper, a low-cost activated carbon(AC) was prepared from deactivated resin catalyst(DRC) for methyl tert-butyl ether(MTBE) synthesis through carbonization and subsequent steam activation treatment. The activated carbon was characterized in detail. After loading various transition metals, including Cu^(2+), Ag+, Co^(2+), Ni^(2+), Zn^(2+), and Fe^(3+) via the ultrasonic-assisted impregnation method, a series of metal-loaded adsorbents(xM-AC) were obtained and their dimethyl sulfide(DMS) adsorption performance was investigated in a batch system. Among these adsorbents, 15Cu-AC presented a superior DMS adsorption capacity equating to 58.986 mg/g due to the formation of S-M(σ) bonds between Cu^(2+) and sulfur atoms of DMS as confirmed by the Raman spectra and kinetic study.展开更多
Oxygen and nitrogen-functionalized carbon nanotubes （OCNTs and NCNTs） were applied as metal-free catalysts in selective olefin hydro- genation. A series of NCNTs was synthesized by NH3 post-treatment of OCNTs. Tempe...Oxygen and nitrogen-functionalized carbon nanotubes （OCNTs and NCNTs） were applied as metal-free catalysts in selective olefin hydro- genation. A series of NCNTs was synthesized by NH3 post-treatment of OCNTs. Temperature-programmed desorption, N2 physisorption, Raman spectroscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy were employed to characterize the surface properties of OCNTs and NCNTs, aiming at a detailed analysis of the type and amount of oxygen- and nitrogen-containing groups as well as surface defects. The gas-phase treatments applied for oxygen and nitrogen functionalization at elevated temperatures up to 600 ℃ led to the increase of surface defects, but did not cause structural damages in the bulk. NCNTs showed a clearly higher activity than the pristine CNTs and OCNTs in the hydrogenation of 1,5-cyclooctadiene, and also the selectivity to cyclooctene was higher. The favorable catalytic properties are ascribed to the nitrogen-containing surface functional groups as well as surface defects related to nitrogen species. In contrast, oxygen-containing surface groups and the surface defects caused by oxygen species did not show clear contribution to the hydrogenation catalysis.展开更多
Electrochemical carbon dioxide reduction reaction(CO_(2)RR)provides an attractive approach to carbon capture and utilization for the production high-value-added products.However,CO_(2)RR still suffers from poor select...Electrochemical carbon dioxide reduction reaction(CO_(2)RR)provides an attractive approach to carbon capture and utilization for the production high-value-added products.However,CO_(2)RR still suffers from poor selectivity and low current density due to its sluggish kinetics and multitudinous reaction pathways.Single-atom catalysts(SACs)demonstrate outstanding activity,excellent selectivity,and remarkable atom utilization efficiency,which give impetus to the search for electrocatalytic processes aiming at high selectivity.There appears significant activity in the development of efficient SACs for CO_(2)RR,while the density of the atomic sites remains a considerable barrier to be overcome.To construct high-metal-loading SACs,aggregation must be prevented,and thus novel strategies are required.The key to creating high-density atomically dispersed sites is designing enough anchoring sites,normally defects,to stabilize the highly mobile separated metal atoms.In this review,we summarized the advances in developing high-loading SACs through defect engineering,with a focus on the synthesis strategies to achieve high atomic site loading.Finally,the future opportunities and challenges for CO_(2)RR in the area of high-loading single-atom electrocatalysts are also discussed.展开更多
Accelerating the rate-limiting oxygen reduction reaction （ORR） at the cathode remains the foremost issue for the commercialization of fuel cells. Transition metal-nitrogen-carbon （M-N/C, M = Fe, Co, etc.） nanostru...Accelerating the rate-limiting oxygen reduction reaction （ORR） at the cathode remains the foremost issue for the commercialization of fuel cells. Transition metal-nitrogen-carbon （M-N/C, M = Fe, Co, etc.） nanostructures are the most promising class of non-precious metal catalysts （NPMCs） with satisfactory activities and stabilities in practical fuel cell applications. However, the long-debated nature of the active sites and the elusive structure-performance correlation impede further developments of M-N/C materials. In this review, we present recent endeavors to elucidate the actual structures of active sites by adopting a variety of physicochemical techniques that may provide a profound mechanistic understanding of M-N/C catalysts. Then, we focus on the spectacular progress in structural optimization strategies for M-N/C materials with tailored precursor architectures and modified synthetic routes for controlling the structural uniformity and maximizing the number of active sites in catalytic materials. The recognition of the right active centers and site-specific engineering of the nanostructures provides future directions for designing advantageous M-N/C catalysts.展开更多
Reverse water gas shift（RWGS） reaction can be served as a pivotal stage of transitioning the abundant CO;resource into chemicals or hydrocarbon fuels, which is attractive for the CO;utilization and of eventually sig...Reverse water gas shift（RWGS） reaction can be served as a pivotal stage of transitioning the abundant CO;resource into chemicals or hydrocarbon fuels, which is attractive for the CO;utilization and of eventually significance in enabling a rebuilt ecological system for unconventional fuels. This concept is appealing when the process is considered as a solution for the storage of renewable energy, which may also find a variety of potential end uses for the outer space exploration. However, a big challenge to this issue is the rational design of high temperature endurable RWGS catalysts with desirable CO product selectivity. In this work, we present a comprehensive overview of recent publications on this research topic,mainly focusing on the catalytic performance of RWGS reaction over three major kinds of heterogeneous catalysts, including supported metal catalysts, mixed oxide catalysts and transition metal carbides. The reaction thermodynamic analysis, kinetics and mechanisms are also described in detail. The present review attempts to provide a general guideline about the construction of well-performed heterogeneous catalysts for the RWGS reaction, as well as discussing the challenges and further prospects of this process.展开更多
Reversible oxygen reaction plays a crucial role in rechargeable battery systems,but it is limited by the slow reaction kinetics.Herein,the ionic modulation of cobalt pentlandite coupled with nitrogen‐doped bowl‐like...Reversible oxygen reaction plays a crucial role in rechargeable battery systems,but it is limited by the slow reaction kinetics.Herein,the ionic modulation of cobalt pentlandite coupled with nitrogen‐doped bowl‐like hollow carbon sphere is well designed on octahedral and tetrahedral sites.The robust FexCo9−xS8‐NHCS‐V with iron replacing at the octahedron possesses prolonged metal sulfur bond and exhibits excellent bifunctional electrocatalytic performance towards oxygen reduction reaction(ORR,E_(1/2)=0.80 V vs.RHE)and excellent oxygen evolution reaction(OER,E_(j=10)=1.53 V vs.RHE)in 0.1 mol/L KOH.Accordingly,a rechargeable Zn‐air battery of Fe_(x)Co_(9−x)S_(8)‐NHCS‐V cathode endows high energy efficiency(102 mW cm^(−2)),and a microbial fuel cell achieves a high‐power density(791±42 mW m^(−2)),outperforming the benchmark Pt/C catalyst.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financially supported by the National Natural Science Foundation of China (No. 21276086)
文摘In this paper, a low-cost activated carbon(AC) was prepared from deactivated resin catalyst(DRC) for methyl tert-butyl ether(MTBE) synthesis through carbonization and subsequent steam activation treatment. The activated carbon was characterized in detail. After loading various transition metals, including Cu^(2+), Ag+, Co^(2+), Ni^(2+), Zn^(2+), and Fe^(3+) via the ultrasonic-assisted impregnation method, a series of metal-loaded adsorbents(xM-AC) were obtained and their dimethyl sulfide(DMS) adsorption performance was investigated in a batch system. Among these adsorbents, 15Cu-AC presented a superior DMS adsorption capacity equating to 58.986 mg/g due to the formation of S-M(σ) bonds between Cu^(2+) and sulfur atoms of DMS as confirmed by the Raman spectra and kinetic study.
基金supported by the German Federal Ministry of Education and Research (BMBF) for the CarboKat Project (03X0204D) within the scope of the Inno.CNT Alliance
文摘Oxygen and nitrogen-functionalized carbon nanotubes （OCNTs and NCNTs） were applied as metal-free catalysts in selective olefin hydro- genation. A series of NCNTs was synthesized by NH3 post-treatment of OCNTs. Temperature-programmed desorption, N2 physisorption, Raman spectroscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy were employed to characterize the surface properties of OCNTs and NCNTs, aiming at a detailed analysis of the type and amount of oxygen- and nitrogen-containing groups as well as surface defects. The gas-phase treatments applied for oxygen and nitrogen functionalization at elevated temperatures up to 600 ℃ led to the increase of surface defects, but did not cause structural damages in the bulk. NCNTs showed a clearly higher activity than the pristine CNTs and OCNTs in the hydrogenation of 1,5-cyclooctadiene, and also the selectivity to cyclooctene was higher. The favorable catalytic properties are ascribed to the nitrogen-containing surface functional groups as well as surface defects related to nitrogen species. In contrast, oxygen-containing surface groups and the surface defects caused by oxygen species did not show clear contribution to the hydrogenation catalysis.
基金This project was supported by the National Natural Science Foundation of China(U19A2017,22272206,51976143)Natural Science Foundation of Hunan Province(S2021JJMSXM3153).
文摘Electrochemical carbon dioxide reduction reaction(CO_(2)RR)provides an attractive approach to carbon capture and utilization for the production high-value-added products.However,CO_(2)RR still suffers from poor selectivity and low current density due to its sluggish kinetics and multitudinous reaction pathways.Single-atom catalysts(SACs)demonstrate outstanding activity,excellent selectivity,and remarkable atom utilization efficiency,which give impetus to the search for electrocatalytic processes aiming at high selectivity.There appears significant activity in the development of efficient SACs for CO_(2)RR,while the density of the atomic sites remains a considerable barrier to be overcome.To construct high-metal-loading SACs,aggregation must be prevented,and thus novel strategies are required.The key to creating high-density atomically dispersed sites is designing enough anchoring sites,normally defects,to stabilize the highly mobile separated metal atoms.In this review,we summarized the advances in developing high-loading SACs through defect engineering,with a focus on the synthesis strategies to achieve high atomic site loading.Finally,the future opportunities and challenges for CO_(2)RR in the area of high-loading single-atom electrocatalysts are also discussed.
文摘Accelerating the rate-limiting oxygen reduction reaction （ORR） at the cathode remains the foremost issue for the commercialization of fuel cells. Transition metal-nitrogen-carbon （M-N/C, M = Fe, Co, etc.） nanostructures are the most promising class of non-precious metal catalysts （NPMCs） with satisfactory activities and stabilities in practical fuel cell applications. However, the long-debated nature of the active sites and the elusive structure-performance correlation impede further developments of M-N/C materials. In this review, we present recent endeavors to elucidate the actual structures of active sites by adopting a variety of physicochemical techniques that may provide a profound mechanistic understanding of M-N/C catalysts. Then, we focus on the spectacular progress in structural optimization strategies for M-N/C materials with tailored precursor architectures and modified synthetic routes for controlling the structural uniformity and maximizing the number of active sites in catalytic materials. The recognition of the right active centers and site-specific engineering of the nanostructures provides future directions for designing advantageous M-N/C catalysts.
基金supported by the National Natural Science Foundation of China(Nos.21506204 and 21476226)China Ministry of Science and Technology under contact of 2016YFB0600902+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB17020400)State Grid Cooperation of China(SGRI-DL-71-16-015)Dalian Science Foundation for Distinguished Young Scholars(2016RJ04)the Youth Innovation Promotion Association of CAS
文摘Reverse water gas shift（RWGS） reaction can be served as a pivotal stage of transitioning the abundant CO;resource into chemicals or hydrocarbon fuels, which is attractive for the CO;utilization and of eventually significance in enabling a rebuilt ecological system for unconventional fuels. This concept is appealing when the process is considered as a solution for the storage of renewable energy, which may also find a variety of potential end uses for the outer space exploration. However, a big challenge to this issue is the rational design of high temperature endurable RWGS catalysts with desirable CO product selectivity. In this work, we present a comprehensive overview of recent publications on this research topic,mainly focusing on the catalytic performance of RWGS reaction over three major kinds of heterogeneous catalysts, including supported metal catalysts, mixed oxide catalysts and transition metal carbides. The reaction thermodynamic analysis, kinetics and mechanisms are also described in detail. The present review attempts to provide a general guideline about the construction of well-performed heterogeneous catalysts for the RWGS reaction, as well as discussing the challenges and further prospects of this process.
文摘Reversible oxygen reaction plays a crucial role in rechargeable battery systems,but it is limited by the slow reaction kinetics.Herein,the ionic modulation of cobalt pentlandite coupled with nitrogen‐doped bowl‐like hollow carbon sphere is well designed on octahedral and tetrahedral sites.The robust FexCo9−xS8‐NHCS‐V with iron replacing at the octahedron possesses prolonged metal sulfur bond and exhibits excellent bifunctional electrocatalytic performance towards oxygen reduction reaction(ORR,E_(1/2)=0.80 V vs.RHE)and excellent oxygen evolution reaction(OER,E_(j=10)=1.53 V vs.RHE)in 0.1 mol/L KOH.Accordingly,a rechargeable Zn‐air battery of Fe_(x)Co_(9−x)S_(8)‐NHCS‐V cathode endows high energy efficiency(102 mW cm^(−2)),and a microbial fuel cell achieves a high‐power density(791±42 mW m^(−2)),outperforming the benchmark Pt/C catalyst.
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.
