The Pt decorated Ni/C nanocatalysts were prepared for hydrogen oxidation reaction(HOR) in fuel cell.By regulating the contents of Pt and Ni in the catalyst,both the composition and the structure affected the electro...The Pt decorated Ni/C nanocatalysts were prepared for hydrogen oxidation reaction(HOR) in fuel cell.By regulating the contents of Pt and Ni in the catalyst,both the composition and the structure affected the electrochemical catalytic characteristics of the Pt-Ni/C catalysts.When the Pt mass content was 3.1% percent and that of Ni was 13.9% percent,the Pt-Ni/C-3 catalyst exhibited a larger electrochemically active surface area and a higher exchange current density toward HOR than those of pure supported platinum sample.Our study demonstrates a feasible approach for designing the more efficient catalysts with lower content of noble metal for HOR in fuel cell.展开更多
Proton exchange membrane fuel cells(PEMFCs) are considered a promising power source for electric vehicles and stationary residential applications. However, current PEMFCs have several problems that require solutions, ...Proton exchange membrane fuel cells(PEMFCs) are considered a promising power source for electric vehicles and stationary residential applications. However, current PEMFCs have several problems that require solutions, including high cost, insufficient power density, and limited performance durability. A kinetically sluggish oxygen reduction reaction(ORR) is primarily responsible for these issues. The development of advanced Pt-based catalysts is crucial for solving these problems if the large-scale application of PEMFCs is to be realized. In this review, we summarize the recent progress in the development of Pt M alloy(M = Fe, Co, Ni, etc.) catalysts with an emphasis on ordered Pt M intermetallic catalysts, which exhibit significantly enhanced activity and stability. In addition to exploring the intrinsic catalytic performance in traditional aqueous electrolytes via engineering nanostructures, morphologies, and crystallinity of Pt M particles, we highlight recent efforts to study catalysts under real fuel cell environments by the membrane electrode assembly(MEA).展开更多
The electrocatalytic activity toward oxygen reduction reaction is studied on the perovskite oxide La~_xbrxMnt)3, as preparea under different firing temperatures. X-ray diffraction shows that three different crystal p...The electrocatalytic activity toward oxygen reduction reaction is studied on the perovskite oxide La~_xbrxMnt)3, as preparea under different firing temperatures. X-ray diffraction shows that three different crystal phases featuring tetragonal, cubic, and orthorhombic symmetries form with increasing crystallinities. The electrocatalytic activity is characterized by cyclic voltam- metry and linear sweeping voltammetry for the three phases of La1-xSrxMnO3. We find that the tetragonal phase has the best catalytic activity among the three crystal phases, with the largest onset potential of 0.147 V. The synergistic effect between the volume per unit cell and crystallinity is indicated to account for the good catalytic activity of the tetragonal phase.展开更多
The Pt-based catalyst tends to be poisoned by carbon monoxide(CO)-like intermediates produced in fuel cell reactions,which seriously deteriorates its catalytic performance.Herein,noble metal Au with the capacity of re...The Pt-based catalyst tends to be poisoned by carbon monoxide(CO)-like intermediates produced in fuel cell reactions,which seriously deteriorates its catalytic performance.Herein,noble metal Au with the capacity of resistance to CO-like intermediates poisoning was employed to construct multi-element Pt-based catalysts.Two trimetallic NiPtAu hollow nanocrystals(HNCs)with different surface Au contents were synthesized to explore the role of Au in electrocatalysis for alkaline methanol oxidation reaction(MOR).The trimetallic NiPtAu-SRAu HNCs catalyst with the relative rich Au content(15.17 at%)on surface exhibits a much lower CO oxidation peak potential than the other HNCs counterpart and 20 wt%Pt/C,which indicates the more exceptional CO-resisting performance.Besides,the MOR specific activity of NiPtAu-SRAu HNCs(31.52 mA cm^−2)is 7 times higher than that of 20wt%Pt/C(4.50 mA cm^−2).This enhancement in catalytic activity as well as anti-CO poisoning capability for NiPtAu-SRAu HNCs can be mainly ascribed to the weakened CO adsorption due to the exposure of Au atoms on NiPt surface evidenced by the experimental data and density functional theory calculations.This study not only investigates the role of Au in MOR catalysis but also could be helpful for designing and optimizing the electrocatalysts for high-active and robust fuel cell applications.展开更多
The sluggish oxygen evolution reaction (OER) is an important half-reaction of the electrochemical water-splitting reaction. Amorphous Fe/Ni composite oxides have high activity. In this work, we modified the aerosol ...The sluggish oxygen evolution reaction (OER) is an important half-reaction of the electrochemical water-splitting reaction. Amorphous Fe/Ni composite oxides have high activity. In this work, we modified the aerosol spray-assisted approach and obtained amorphous Fe-Ni-Ox solid-solution nanoparticles (Fe-Ni-Ox-NPs) approximately 20 nm in size by choosing iron/nickel acetylacetonates as raw materials instead of inorganic salts. The small-sized Fe-Ni-Ox-NPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Furthermore, an investigation of electrochemical OER performance suggests that the small-sized Fe-Ni-Ox-NPs have higher activity than the large-sized Fe-Ni-Ox-MPs. A small overpotential of 0.315 V was demanded to obtain a working current density of 50 mA/cm2, and the Tafel slope was as low as 38 mWdec.展开更多
Anatase TiO2 microspheres with exposed dominant {001} facets were doped with interstitial boron to have a concentration gradient with the maximum concentration at the surface. They were then further doped with substit...Anatase TiO2 microspheres with exposed dominant {001} facets were doped with interstitial boron to have a concentration gradient with the maximum concentration at the surface. They were then further doped with substitutional nitrogen by heating in an ammonia atmosphere at different temperatures from 440 to 560℃ to give surface N concentrations ranging from 7.03 to 15.47 at%. The optical absorption, atomic and electronic structures and visible-light photoelectrochemical water oxidation activity of these materials were investigated. The maximum activity of the doped TiO2 was achieved at a nitrogen doping temperature of 520℃ that gave a high absorbance over the whole visible light region but with no defect-related background absorption.展开更多
The development of highly efficient and costeffective oxygen evolution reaction(OER)electrocatalysts for renewable energy systems is vitally essential.Modulation of the electronic structure through heteroatom doping i...The development of highly efficient and costeffective oxygen evolution reaction(OER)electrocatalysts for renewable energy systems is vitally essential.Modulation of the electronic structure through heteroatom doping is considered as one of the most potential strategies to boost OER performances.Herein,a rational design of Mn-doped NiFe layered double hydroxide/reduced graphene oxide(Mn-NiFe LDH/rGO)is demonstrated by a facile hydrothermal approach,which exhibits outstanding OER activity and durability.Experimental results and density functional theory(DFT)calculations manifest that the introduction of Mn can reprogram the electronic structure of surface active sites and alter the intermediate adsorption energy,consequently reducing the potential limiting activation energy for OER.Specifically,the optimal Mn-NiFe LDH/rGO composite shows an enhanced OER performance with an ultralow overpotential of 240 mV@10 mA cm^(-2),Tafel slope of 40.0 mV dec^(-1) and excellent stability.Such superior OER activity is comparable to those of the recently reported state-of-the-art OER catalysts.This work presents an advanced strategy for designing electrocatalysts with high activity and low cost for energy conversion applications.展开更多
Cobalt tetra(2,4-dichloro-1,3,5-triazine)aminophthalocyanine (CoPc) was immobilized covalently on activated carbon fiber (ACF) felt to obtain CoPc-modified ACF (CoPc-ACF) catalyst, and an electrocatalytic oxid...Cobalt tetra(2,4-dichloro-1,3,5-triazine)aminophthalocyanine (CoPc) was immobilized covalently on activated carbon fiber (ACF) felt to obtain CoPc-modified ACF (CoPc-ACF) catalyst, and an electrocatalytic oxidation system using CoPc-ACF as the anode was constructed. The electrocatalytic oxidation of Acid Red 1 (ARI) was investigated in aqueous solution by an UV-vis spectrophotometer and UPLC. The results indicated that AR1 could be eliminated efficiently in this electrocatalytic oxidation system. In addition, the results of FTIR, TOC and GC-MS suggested that the electrocatalytic oxidation experienced the decoloration achieved by destroying the azo linkage and the further mineralization due to the cleavages of benzene ring and naphthalene ring. The intermediates were mainly small molecular compounds such as maleic acid and succinic acid, etc. Re- petitive tests showed that CoPc-ACF can maintain high electrocatalytic activity over several cycles. The further EPR spin-trap experiments indicated that the hydroxyl radicals did not dominate the reaction in this electrocatalytic system, which was com- pletely different from the traditional electro-Fenton system. Based on the non-radical reaction mechanism, the CoPc-modified ACF electrocatalyst has potential application in treating actual dyestuffs wastewaters, which are accompanied with high concentration of hydroxyl radical scavengers such as chlorine ions and additives in the textile printing and dyeing industry.展开更多
Cl-containing cerium dioxide(Ce O2) catalysts have been found to exhibit unique catalytic activities. In the present work, using density functional theory calculations with the inclusion of on-site Coulomb correction,...Cl-containing cerium dioxide(Ce O2) catalysts have been found to exhibit unique catalytic activities. In the present work, using density functional theory calculations with the inclusion of on-site Coulomb correction, we systematically studied the effect of Cl on the physicochemical properties of Ce O2 surfaces by substituting one subsurface O with Cl. The calculated results show that substituting an O atom with a Cl atom results in structural distortion and the reduction of one surface Ce4+ cation to Ce3+. The protruding Ce3+ cation greatly improves the adsorption energy of O2 to produce an active O2- species, and maintains the catalytic oxidation cycle of CO on Ce O2(110). These results may help us obtain a better understanding of Cl-ceria interacting systems and provide some guidance for the design of effective Ce O2-based catalysts.展开更多
Transition metal alloy electrocatalysts have sparked intense interest for their use in oxygen reduction reaction(ORR).However,there is almost no corresponding research on the alloy active sites.In this study,CoNi allo...Transition metal alloy electrocatalysts have sparked intense interest for their use in oxygen reduction reaction(ORR).However,there is almost no corresponding research on the alloy active sites.In this study,CoNi alloy nanoparticles embedded in bamboo-like N-doped carbon nanotubes(CoNi-NCTs)as catalysts constructed by a facile pyrolysis of Prussian blue analogs were investigated.The density functional theory calculation reveals that the oxygen molecules are more easily adsorbed on the Ni sites in these catalysts,while the Co sites favor the formation of OOH★intermediates during ORR.In addition,the cooperation of the CoNi alloys with the N-doped carbon benefits electron transfer and promotes electrocatalytic activity.The optimized CoNi-NCT shows remarkable ORR catalytic activity with an half-wave potential(E1/2)of 0.83 V,an onset potential(Eonset)of 0.97 V,and superior durability,all of which surpass the commercial Pt/C catalysts.The assembled zinc-air battery delivers a small charge/discharge voltage gap of 0.86 V at 10 mA cm^(-2),a high-power density of 167 mW cm^(-2),and good stability(running stably over 900 cycles).展开更多
Tungsten boride(WB) crystals, whose surface tends to be oxidized when exposed to air, were demonstrated to have a comparable activity to platinum as counter electrode material in dye-sensitized solar cells. The synerg...Tungsten boride(WB) crystals, whose surface tends to be oxidized when exposed to air, were demonstrated to have a comparable activity to platinum as counter electrode material in dye-sensitized solar cells. The synergistic effect of both catalytically active surface layer WOxand electronically conductive internal WB is considered to be responsible for the high activity of the WB crystals.展开更多
Synthesis of shape-controlled Pt nanocrystals is substantial and important for enhancing chemical and electrochemical reactions.However,the removal of capping agents,shape-controlling chemicals,on Pt surfaces is essen...Synthesis of shape-controlled Pt nanocrystals is substantial and important for enhancing chemical and electrochemical reactions.However,the removal of capping agents,shape-controlling chemicals,on Pt surfaces is essential prior to conducting the catalytic reactions.Here we report a facile one-pot synthesis of Pt nanocubes directly grown on carbon supports(Pt nanocubes/C) with modulating the kinetic reaction factors for shaping the nanocrystals,but without adding any capping agents for preserving the clean Pt surfaces.Well-dispersed Pt nanocubes/C shows enhanced activity and long-term stability toward methanol oxidation reaction compared to the commercial Pt/C catalyst.展开更多
基金supported by the National Natural Science Foundation of China (21476145)~~
文摘The Pt decorated Ni/C nanocatalysts were prepared for hydrogen oxidation reaction(HOR) in fuel cell.By regulating the contents of Pt and Ni in the catalyst,both the composition and the structure affected the electrochemical catalytic characteristics of the Pt-Ni/C catalysts.When the Pt mass content was 3.1% percent and that of Ni was 13.9% percent,the Pt-Ni/C-3 catalyst exhibited a larger electrochemically active surface area and a higher exchange current density toward HOR than those of pure supported platinum sample.Our study demonstrates a feasible approach for designing the more efficient catalysts with lower content of noble metal for HOR in fuel cell.
文摘Proton exchange membrane fuel cells(PEMFCs) are considered a promising power source for electric vehicles and stationary residential applications. However, current PEMFCs have several problems that require solutions, including high cost, insufficient power density, and limited performance durability. A kinetically sluggish oxygen reduction reaction(ORR) is primarily responsible for these issues. The development of advanced Pt-based catalysts is crucial for solving these problems if the large-scale application of PEMFCs is to be realized. In this review, we summarize the recent progress in the development of Pt M alloy(M = Fe, Co, Ni, etc.) catalysts with an emphasis on ordered Pt M intermetallic catalysts, which exhibit significantly enhanced activity and stability. In addition to exploring the intrinsic catalytic performance in traditional aqueous electrolytes via engineering nanostructures, morphologies, and crystallinity of Pt M particles, we highlight recent efforts to study catalysts under real fuel cell environments by the membrane electrode assembly(MEA).
基金supported by the National Basic Research Program of China(2012CB215504)the National High Technology Research and Development Program of China(2009AA034401)the National Natural Science Foundation of China(50632050)
文摘The electrocatalytic activity toward oxygen reduction reaction is studied on the perovskite oxide La~_xbrxMnt)3, as preparea under different firing temperatures. X-ray diffraction shows that three different crystal phases featuring tetragonal, cubic, and orthorhombic symmetries form with increasing crystallinities. The electrocatalytic activity is characterized by cyclic voltam- metry and linear sweeping voltammetry for the three phases of La1-xSrxMnO3. We find that the tetragonal phase has the best catalytic activity among the three crystal phases, with the largest onset potential of 0.147 V. The synergistic effect between the volume per unit cell and crystallinity is indicated to account for the good catalytic activity of the tetragonal phase.
基金the National Natural Science Foundation of China(91963113,51701139,51671143 and U1601216)。
文摘The Pt-based catalyst tends to be poisoned by carbon monoxide(CO)-like intermediates produced in fuel cell reactions,which seriously deteriorates its catalytic performance.Herein,noble metal Au with the capacity of resistance to CO-like intermediates poisoning was employed to construct multi-element Pt-based catalysts.Two trimetallic NiPtAu hollow nanocrystals(HNCs)with different surface Au contents were synthesized to explore the role of Au in electrocatalysis for alkaline methanol oxidation reaction(MOR).The trimetallic NiPtAu-SRAu HNCs catalyst with the relative rich Au content(15.17 at%)on surface exhibits a much lower CO oxidation peak potential than the other HNCs counterpart and 20 wt%Pt/C,which indicates the more exceptional CO-resisting performance.Besides,the MOR specific activity of NiPtAu-SRAu HNCs(31.52 mA cm^−2)is 7 times higher than that of 20wt%Pt/C(4.50 mA cm^−2).This enhancement in catalytic activity as well as anti-CO poisoning capability for NiPtAu-SRAu HNCs can be mainly ascribed to the weakened CO adsorption due to the exposure of Au atoms on NiPt surface evidenced by the experimental data and density functional theory calculations.This study not only investigates the role of Au in MOR catalysis but also could be helpful for designing and optimizing the electrocatalysts for high-active and robust fuel cell applications.
文摘The sluggish oxygen evolution reaction (OER) is an important half-reaction of the electrochemical water-splitting reaction. Amorphous Fe/Ni composite oxides have high activity. In this work, we modified the aerosol spray-assisted approach and obtained amorphous Fe-Ni-Ox solid-solution nanoparticles (Fe-Ni-Ox-NPs) approximately 20 nm in size by choosing iron/nickel acetylacetonates as raw materials instead of inorganic salts. The small-sized Fe-Ni-Ox-NPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Furthermore, an investigation of electrochemical OER performance suggests that the small-sized Fe-Ni-Ox-NPs have higher activity than the large-sized Fe-Ni-Ox-MPs. A small overpotential of 0.315 V was demanded to obtain a working current density of 50 mA/cm2, and the Tafel slope was as low as 38 mWdec.
基金supported by the Major Basic Research Program, Ministry of Science and Technology of China (2014CB239401)the National Natural Science Fundation of China (51422210, 21633009, 51629201 and 51521091)the Key Research Program of Frontier Sciences CAS (QYZDB-SSW-JSC039)
文摘Anatase TiO2 microspheres with exposed dominant {001} facets were doped with interstitial boron to have a concentration gradient with the maximum concentration at the surface. They were then further doped with substitutional nitrogen by heating in an ammonia atmosphere at different temperatures from 440 to 560℃ to give surface N concentrations ranging from 7.03 to 15.47 at%. The optical absorption, atomic and electronic structures and visible-light photoelectrochemical water oxidation activity of these materials were investigated. The maximum activity of the doped TiO2 was achieved at a nitrogen doping temperature of 520℃ that gave a high absorbance over the whole visible light region but with no defect-related background absorption.
基金the National Natural Science Foundation of China(51902003 and 21771003)Anhui Province Natural Science Foundation(2008085QB53)the Natural Science Research Project of Anhui Province Education Department(KJ2019A0581)。
文摘The development of highly efficient and costeffective oxygen evolution reaction(OER)electrocatalysts for renewable energy systems is vitally essential.Modulation of the electronic structure through heteroatom doping is considered as one of the most potential strategies to boost OER performances.Herein,a rational design of Mn-doped NiFe layered double hydroxide/reduced graphene oxide(Mn-NiFe LDH/rGO)is demonstrated by a facile hydrothermal approach,which exhibits outstanding OER activity and durability.Experimental results and density functional theory(DFT)calculations manifest that the introduction of Mn can reprogram the electronic structure of surface active sites and alter the intermediate adsorption energy,consequently reducing the potential limiting activation energy for OER.Specifically,the optimal Mn-NiFe LDH/rGO composite shows an enhanced OER performance with an ultralow overpotential of 240 mV@10 mA cm^(-2),Tafel slope of 40.0 mV dec^(-1) and excellent stability.Such superior OER activity is comparable to those of the recently reported state-of-the-art OER catalysts.This work presents an advanced strategy for designing electrocatalysts with high activity and low cost for energy conversion applications.
基金supported by the National Natural Science Foundation of China(51133006,51103133,51003096)Program for Changjiang Scholars and Innovative Research Team in University(0654)Textile Vision Science & Education Fund and Science Foundation of Zhejiang SciTech University(1001803-Y)
文摘Cobalt tetra(2,4-dichloro-1,3,5-triazine)aminophthalocyanine (CoPc) was immobilized covalently on activated carbon fiber (ACF) felt to obtain CoPc-modified ACF (CoPc-ACF) catalyst, and an electrocatalytic oxidation system using CoPc-ACF as the anode was constructed. The electrocatalytic oxidation of Acid Red 1 (ARI) was investigated in aqueous solution by an UV-vis spectrophotometer and UPLC. The results indicated that AR1 could be eliminated efficiently in this electrocatalytic oxidation system. In addition, the results of FTIR, TOC and GC-MS suggested that the electrocatalytic oxidation experienced the decoloration achieved by destroying the azo linkage and the further mineralization due to the cleavages of benzene ring and naphthalene ring. The intermediates were mainly small molecular compounds such as maleic acid and succinic acid, etc. Re- petitive tests showed that CoPc-ACF can maintain high electrocatalytic activity over several cycles. The further EPR spin-trap experiments indicated that the hydroxyl radicals did not dominate the reaction in this electrocatalytic system, which was com- pletely different from the traditional electro-Fenton system. Based on the non-radical reaction mechanism, the CoPc-modified ACF electrocatalyst has potential application in treating actual dyestuffs wastewaters, which are accompanied with high concentration of hydroxyl radical scavengers such as chlorine ions and additives in the textile printing and dyeing industry.
基金supported by the National Basic Research Program of China(2011CB808505)the National Natural Science Foundation of China(21322307,21421004)+1 种基金the"Shu Guang"project of Shanghai Municipal Education CommissionShanghai Education Development Foundation(13SG30)for financial support
文摘Cl-containing cerium dioxide(Ce O2) catalysts have been found to exhibit unique catalytic activities. In the present work, using density functional theory calculations with the inclusion of on-site Coulomb correction, we systematically studied the effect of Cl on the physicochemical properties of Ce O2 surfaces by substituting one subsurface O with Cl. The calculated results show that substituting an O atom with a Cl atom results in structural distortion and the reduction of one surface Ce4+ cation to Ce3+. The protruding Ce3+ cation greatly improves the adsorption energy of O2 to produce an active O2- species, and maintains the catalytic oxidation cycle of CO on Ce O2(110). These results may help us obtain a better understanding of Cl-ceria interacting systems and provide some guidance for the design of effective Ce O2-based catalysts.
基金the National Key R&D Program of China(2018YFE0201704)the National Natural Science Foundation of China(21771059,21631004 and 91961111)the Natural Science Foundation of Heilongjiang Province(YQ2019B007)。
文摘Transition metal alloy electrocatalysts have sparked intense interest for their use in oxygen reduction reaction(ORR).However,there is almost no corresponding research on the alloy active sites.In this study,CoNi alloy nanoparticles embedded in bamboo-like N-doped carbon nanotubes(CoNi-NCTs)as catalysts constructed by a facile pyrolysis of Prussian blue analogs were investigated.The density functional theory calculation reveals that the oxygen molecules are more easily adsorbed on the Ni sites in these catalysts,while the Co sites favor the formation of OOH★intermediates during ORR.In addition,the cooperation of the CoNi alloys with the N-doped carbon benefits electron transfer and promotes electrocatalytic activity.The optimized CoNi-NCT shows remarkable ORR catalytic activity with an half-wave potential(E1/2)of 0.83 V,an onset potential(Eonset)of 0.97 V,and superior durability,all of which surpass the commercial Pt/C catalysts.The assembled zinc-air battery delivers a small charge/discharge voltage gap of 0.86 V at 10 mA cm^(-2),a high-power density of 167 mW cm^(-2),and good stability(running stably over 900 cycles).
基金supported by the National Basic Research Program of China(2014CB239401)the National Natural Science Foundation of China(51422210,51629201,51521091)
文摘Tungsten boride(WB) crystals, whose surface tends to be oxidized when exposed to air, were demonstrated to have a comparable activity to platinum as counter electrode material in dye-sensitized solar cells. The synergistic effect of both catalytically active surface layer WOxand electronically conductive internal WB is considered to be responsible for the high activity of the WB crystals.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(NRF-2015R1D1A3A01019467,NRF2017R1D1A1B03031892) and KBSI(D37614)
文摘Synthesis of shape-controlled Pt nanocrystals is substantial and important for enhancing chemical and electrochemical reactions.However,the removal of capping agents,shape-controlling chemicals,on Pt surfaces is essential prior to conducting the catalytic reactions.Here we report a facile one-pot synthesis of Pt nanocubes directly grown on carbon supports(Pt nanocubes/C) with modulating the kinetic reaction factors for shaping the nanocrystals,but without adding any capping agents for preserving the clean Pt surfaces.Well-dispersed Pt nanocubes/C shows enhanced activity and long-term stability toward methanol oxidation reaction compared to the commercial Pt/C catalyst.