Nano Research volume 13,pages2175–2182(2020)Cite this article 208 Accesses 1 Altmetric Metrics details Abstract Efficient,robust and cost-effective bifunctional oxygen electrocatalysts for oxygen reduction reaction(O...Nano Research volume 13,pages2175–2182(2020)Cite this article 208 Accesses 1 Altmetric Metrics details Abstract Efficient,robust and cost-effective bifunctional oxygen electrocatalysts for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are of vital importance to the widespread utilization of Zn-air batteries.Here we report the fabrication of a bubble-like N,S-codoped porous carbon nanofibers with encapsulated fine Fe/Fe5C2 nanocrystals(∼10 nm)(FeNSCs)by a facile one-pot pyrolysis strategy.The novel FeNSC nanostructures with high Fe content(37.3 wt.%),and synergetic N and S doping demonstrate remarkable ORR and OER catalytic activities in alkaline condition.Particularly for ORR,the optimal FeNSC catalyst exhibits superior performance in terms of current density and durability in both alkaline and acidic media.Moreover,as catalysts on the air electrodes of Zn-air batteries,the optimal FeNSCs show a high peak power density of 59.6 mW/cm^2 and extraordinary discharge-charge cycling performance for 200 h with negligible voltage gap change of only 8%at current density of 20 mA/cm,surpassing its noble metal counterpart(i.e.Pt).The impressive battery stability can be attributed to favorable electron transfer resulting from appropriate graphitization of the bubble-like carbon nanofibers and thorough protection of Fe/Fe5C2 nanoparticles by carbon wrapping to prevent oxidation,agglomeration and dissolution of Fe nanoparticles during battery cycling.The present FeNSC catalyst,which is highly active,robust yet affordable,shows promising prospects in large-scale applications,such as metal-air batteries and fuel cells.展开更多
Highly dispersed and stable Pt-based catalysts play a crucial role in constructing efficient catalytic systems for alkane dehydrogenation.In this study,a novel bimetallic Pt-Sn catalyst confined in extra-large-pore EC...Highly dispersed and stable Pt-based catalysts play a crucial role in constructing efficient catalytic systems for alkane dehydrogenation.In this study,a novel bimetallic Pt-Sn catalyst confined in extra-large-pore ECNU-46 zeolite(denoted as Pt/Sn-ECNU-46)is prepared by post-treatment.The open-site framework Sn species((SiO)_(3)Sn-OH)serve as anchors to interact with Pt species,favoring the high dispersion of Pt.On the other hand,the framework Sn species act as the second metal to regulate the geometrical and electronic environment of Pt species,thus suppressing their accumulation.Pt/Sn-ECNU-46 achieves a good performance in propane dehy-drogenation(PDH)reaction with high initial propane conversion(46%)and propylene selectivity(>99%)as well as regeneration ability.In addition,Pt/Sn-ECNU-46 is also active in the dehydrogenation of n-hexane.This study explores the application of extra-large-pore zeolite as support in constructing metal-confined catalysts for alkane dehydrogenation.展开更多
Developing transition metal-nitrogen-carbon materials(M-N-C)as electrocatalysts for the oxygen evolution reaction(OER)is significant for low-cost energy conversion systems.Further d-orbital adjustment of M center in M...Developing transition metal-nitrogen-carbon materials(M-N-C)as electrocatalysts for the oxygen evolution reaction(OER)is significant for low-cost energy conversion systems.Further d-orbital adjustment of M center in M-N-C is beneficial to the improvement of OER performance.Herein,we synthesize a single-Mn-atom catalyst based on carbon skeleton(Mn_(1)-N_(2)S_(2)C_(x))with isolated Mn-N_(2)S_(2)sites,which exhibits high alkaline OER activity(η10=280 mV),low Tafel slope(44 mV·dec^(−1)),and excellent stability.Theoretical calculations reveal the pivotal function of isolated Mn-N_(2)S_(2)sites in promoting OER,including the adsorption kinetics of intermediates and activation mechanism of active sites.The doping of S causes the increase in both charge density and work function of active Mn center,and ortho-Mn_(1)-N_(2)S_(2)C_(x)expresses the fastest OER kinetics due to the asymmetric plane.展开更多
The on-purpose direct propane dehydrogenation(PDH) has received extensive attention to meet the everincreasing demand of propylene.In this work,by means of density functional theory(DFT) calculations,we systematically...The on-purpose direct propane dehydrogenation(PDH) has received extensive attention to meet the everincreasing demand of propylene.In this work,by means of density functional theory(DFT) calculations,we systematically studied the intrinsic coordinating effect of Fe single-atom catalysts in PDH.Interestingly,the N and P dual-coordinated single Fe(Fe-N_(3)P-C) significantly outperform the Fe-N_(4-)C site in catalysis and exhibit desired activity and selectivity at industrial PDH temperatures.The mechanistic origin of different performance on Fe-N_(3)P-C and Fe-N_(4-)C has been ascribed to the geometric effect.To be specific,the in-plane configuration of Fe-N_(4) site exhibits low H affinity,which results in poor activity in C-H bond activations.By contrast,the out-of-plane structure of Fe-N_(3)P-C site exhibits moderate H affinity,which not only promote the C-H bond scission but also offer a platform for obtaining appropriate H diffusion rate which ensures the high selectivity of propylene and the regeneration of catalysts.This work demonstrates promising applications of dual-coordinated single-atom catalysts for highly selective propane dehydrogenation.展开更多
Hydrogen peroxide (H_(2)O_(2)) is a valuable chemical for a wide variety of applications. The environmentally friendly production route of the electrochemical reduction of O_(2)to H_(2)O_(2) has become an attractive a...Hydrogen peroxide (H_(2)O_(2)) is a valuable chemical for a wide variety of applications. The environmentally friendly production route of the electrochemical reduction of O_(2)to H_(2)O_(2) has become an attractive alternative to the traditional anthraquinone process. The efficiency of electrosynthesis process depends considerably on the availability of cost-effective catalysts with high selectivity, activity, and stability.Currently, there are many outstanding issues in the preparation of highly selective catalysts, the exploration of the interface electrolysis environment, and the construction of electrolysis devices, which have led to extensive research efforts. Distinct from the existing few comprehensive review articles on H_(2)O_(2) production by two-electron oxygen reduction, the present review first explains the principle of the oxygen reduction reaction and then highlights recent advances in the regulation and control strategies of different types of catalysts. Key factors of electrode structure and device design are discussed. In addition,we highlight the promising co-production combination of this system with renewable energy or energy storage systems. This review can help introduce the potential of oxygen reduction electrochemical production of high-flux H_(2)O_(2) to the commercial market.展开更多
基金The research presented in this paper was funded by Project 21875200 supported by National Natural Science Foundation of ChinaThe research was also supported by Natural Science Foundation of Jiangsu Province(No.BK20170314).
文摘Nano Research volume 13,pages2175–2182(2020)Cite this article 208 Accesses 1 Altmetric Metrics details Abstract Efficient,robust and cost-effective bifunctional oxygen electrocatalysts for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are of vital importance to the widespread utilization of Zn-air batteries.Here we report the fabrication of a bubble-like N,S-codoped porous carbon nanofibers with encapsulated fine Fe/Fe5C2 nanocrystals(∼10 nm)(FeNSCs)by a facile one-pot pyrolysis strategy.The novel FeNSC nanostructures with high Fe content(37.3 wt.%),and synergetic N and S doping demonstrate remarkable ORR and OER catalytic activities in alkaline condition.Particularly for ORR,the optimal FeNSC catalyst exhibits superior performance in terms of current density and durability in both alkaline and acidic media.Moreover,as catalysts on the air electrodes of Zn-air batteries,the optimal FeNSCs show a high peak power density of 59.6 mW/cm^2 and extraordinary discharge-charge cycling performance for 200 h with negligible voltage gap change of only 8%at current density of 20 mA/cm,surpassing its noble metal counterpart(i.e.Pt).The impressive battery stability can be attributed to favorable electron transfer resulting from appropriate graphitization of the bubble-like carbon nanofibers and thorough protection of Fe/Fe5C2 nanoparticles by carbon wrapping to prevent oxidation,agglomeration and dissolution of Fe nanoparticles during battery cycling.The present FeNSC catalyst,which is highly active,robust yet affordable,shows promising prospects in large-scale applications,such as metal-air batteries and fuel cells.
基金supports from the National Natural Science Foundation of China(22222201)National Key R&D Program of China(2021YFA1501401,2023YFB3810602).
文摘Highly dispersed and stable Pt-based catalysts play a crucial role in constructing efficient catalytic systems for alkane dehydrogenation.In this study,a novel bimetallic Pt-Sn catalyst confined in extra-large-pore ECNU-46 zeolite(denoted as Pt/Sn-ECNU-46)is prepared by post-treatment.The open-site framework Sn species((SiO)_(3)Sn-OH)serve as anchors to interact with Pt species,favoring the high dispersion of Pt.On the other hand,the framework Sn species act as the second metal to regulate the geometrical and electronic environment of Pt species,thus suppressing their accumulation.Pt/Sn-ECNU-46 achieves a good performance in propane dehy-drogenation(PDH)reaction with high initial propane conversion(46%)and propylene selectivity(>99%)as well as regeneration ability.In addition,Pt/Sn-ECNU-46 is also active in the dehydrogenation of n-hexane.This study explores the application of extra-large-pore zeolite as support in constructing metal-confined catalysts for alkane dehydrogenation.
基金supported by the National Natural Science Foundation of China(No.22075099)the Natural Science Foundation of Jilin Province(No.20220101051JC)the Education Department of Jilin Province(No.JJKH20220967KJ)。
文摘Developing transition metal-nitrogen-carbon materials(M-N-C)as electrocatalysts for the oxygen evolution reaction(OER)is significant for low-cost energy conversion systems.Further d-orbital adjustment of M center in M-N-C is beneficial to the improvement of OER performance.Herein,we synthesize a single-Mn-atom catalyst based on carbon skeleton(Mn_(1)-N_(2)S_(2)C_(x))with isolated Mn-N_(2)S_(2)sites,which exhibits high alkaline OER activity(η10=280 mV),low Tafel slope(44 mV·dec^(−1)),and excellent stability.Theoretical calculations reveal the pivotal function of isolated Mn-N_(2)S_(2)sites in promoting OER,including the adsorption kinetics of intermediates and activation mechanism of active sites.The doping of S causes the increase in both charge density and work function of active Mn center,and ortho-Mn_(1)-N_(2)S_(2)C_(x)expresses the fastest OER kinetics due to the asymmetric plane.
基金support from National Science Foundation of China(Nos.21771134,22173067)National Key R&D Program of China(No.2017YFA0204800)+4 种基金Science and Technology Project of Jiangsu Province(No.BZ2020011)Collaborative Innovation Center of Suzhou Nano Science&Technologythe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the 111 Projectthe Science and Technology Development Fund,Macao SAR(FDCT No.0052/2021/A)。
文摘The on-purpose direct propane dehydrogenation(PDH) has received extensive attention to meet the everincreasing demand of propylene.In this work,by means of density functional theory(DFT) calculations,we systematically studied the intrinsic coordinating effect of Fe single-atom catalysts in PDH.Interestingly,the N and P dual-coordinated single Fe(Fe-N_(3)P-C) significantly outperform the Fe-N_(4-)C site in catalysis and exhibit desired activity and selectivity at industrial PDH temperatures.The mechanistic origin of different performance on Fe-N_(3)P-C and Fe-N_(4-)C has been ascribed to the geometric effect.To be specific,the in-plane configuration of Fe-N_(4) site exhibits low H affinity,which results in poor activity in C-H bond activations.By contrast,the out-of-plane structure of Fe-N_(3)P-C site exhibits moderate H affinity,which not only promote the C-H bond scission but also offer a platform for obtaining appropriate H diffusion rate which ensures the high selectivity of propylene and the regeneration of catalysts.This work demonstrates promising applications of dual-coordinated single-atom catalysts for highly selective propane dehydrogenation.
基金supported by the National Natural Science Foundation of China (51702225, 22179089)。
文摘Hydrogen peroxide (H_(2)O_(2)) is a valuable chemical for a wide variety of applications. The environmentally friendly production route of the electrochemical reduction of O_(2)to H_(2)O_(2) has become an attractive alternative to the traditional anthraquinone process. The efficiency of electrosynthesis process depends considerably on the availability of cost-effective catalysts with high selectivity, activity, and stability.Currently, there are many outstanding issues in the preparation of highly selective catalysts, the exploration of the interface electrolysis environment, and the construction of electrolysis devices, which have led to extensive research efforts. Distinct from the existing few comprehensive review articles on H_(2)O_(2) production by two-electron oxygen reduction, the present review first explains the principle of the oxygen reduction reaction and then highlights recent advances in the regulation and control strategies of different types of catalysts. Key factors of electrode structure and device design are discussed. In addition,we highlight the promising co-production combination of this system with renewable energy or energy storage systems. This review can help introduce the potential of oxygen reduction electrochemical production of high-flux H_(2)O_(2) to the commercial market.
