The study of atomically dispersed metal-nitrogen electrocatalysts is still limited in terms of understanding their catalytic mechanism because of the inability to precisely regulate the coordination number and type of...The study of atomically dispersed metal-nitrogen electrocatalysts is still limited in terms of understanding their catalytic mechanism because of the inability to precisely regulate the coordination number and type of N in combination with the metal elements.Inspired by the high catalytic activity and selectivity of natural enzymes,herein,we have designed and fabricated ultrathin carbon nanosheet-supported Mn single-atom catalysts(SACs)with a precise pyrrole-type Mn-N4(PT-MnN4)configuration using a bio-mimicking strategy.The PT-MnN4 SACs display outstanding oxygen reduction reaction(ORR)activity,with a half-wave potential(E_(1/2))of 0.88 V(vs.revisible hydrogen electrode[RHE])and extremely high stability in alkaline media.Moreover,superior ORR activities are also obtained,E_(1/2) of 0.73 V and 0.63 V in acid and neutral electrolytes,respectively,indicating the efficient pH-universal ORR performances.The assembled zinc-air battery using the PT-MnN4 SACs as air cathodes exhibits a high peak power density(175 mW cm^(−2))and long-term stability up to 150 h,implying its promising application in metal-air batteries.This study has paved the way toward the rational design and precise regulation of single-atom electrocatalysts.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
Electrochemical is considered an attractive approach to recycling the pollution NO(NORR)and producing the valuable NH_(3),which could simultaneously solve the two challenging problems,i.e.,NO removal and NH_(3)synthes...Electrochemical is considered an attractive approach to recycling the pollution NO(NORR)and producing the valuable NH_(3),which could simultaneously solve the two challenging problems,i.e.,NO removal and NH_(3)synthesis.Current research efforts focus less on NORR due to the lack of effective catalysts.Herein,based on DFT calculation,we try to explore effective pyrrole-type TM-N_(4)(TM=V,Cr,Mn,Fe,Co,Ni,Cu,Ru,Rh,Ta)catalysts for achieving the direct NORR.Among the investigated systems,Fe-N_(4)exhibits excellent catalytic activity and high NH_(3)selectivity.Moreover,the free energy of adsorption of N*has been proposed as a descriptor to predict and screen the effective TM-N_(4)catalyst for NORR and the crystal orbital halmilton populations(COHP)is used to describe the intrinsic relationship between metal atoms and the adsorption free energy of N^(*)intermediate.This work has provided a theoretical picture of TM-N4catalyzing NO to NH_(3),which will establish guidelines for the rational design of NORR catalysts and other electrochemical reactions.展开更多
The complex [Cu（C5H7O2）（C5H8N2）3]Br·C2H5OH was obtained from a reaction of CuBr, acac, and Hdmpz （Hdmpz=3, 5-dimethylpyrazole） in a mixed solution of ethanol, ether and water. The crystal belongs to monocli...The complex [Cu（C5H7O2）（C5H8N2）3]Br·C2H5OH was obtained from a reaction of CuBr, acac, and Hdmpz （Hdmpz=3, 5-dimethylpyrazole） in a mixed solution of ethanol, ether and water. The crystal belongs to monoclinic system, space group P21/n with a=8.101（5）, b=19.264 （10）, c=17.19（3）A°, β=95.54（2）°, V=2670（5） A°3, Z=4, Mr=577.03, Dc=1.435 g/cm^3, F（000）=1196,μ=2.348 mm^-1, R=0.0500 and wR=0.1188 for 5361 observed reflections （1〉2σ（I））. The Cu（Ⅱ） ion is coordinated by three Hdmpz and one acac to form a distorted square-pyramid. The complex contains an ethanol molecule and a bromide anion outside acting as the counter ion.展开更多
基金support from the Independent Designing Scientific Research Project of Zhejiang Normal University(2020ZS03)the Zhejiang Provincial Ten Thousand Talent Program(2017R52043)+1 种基金support from the Zhejiang Province Basic Public Welfare Research Project(LGF19B070006)supported by the National Natural Science Foundation of China(No.21775138).
文摘The study of atomically dispersed metal-nitrogen electrocatalysts is still limited in terms of understanding their catalytic mechanism because of the inability to precisely regulate the coordination number and type of N in combination with the metal elements.Inspired by the high catalytic activity and selectivity of natural enzymes,herein,we have designed and fabricated ultrathin carbon nanosheet-supported Mn single-atom catalysts(SACs)with a precise pyrrole-type Mn-N4(PT-MnN4)configuration using a bio-mimicking strategy.The PT-MnN4 SACs display outstanding oxygen reduction reaction(ORR)activity,with a half-wave potential(E_(1/2))of 0.88 V(vs.revisible hydrogen electrode[RHE])and extremely high stability in alkaline media.Moreover,superior ORR activities are also obtained,E_(1/2) of 0.73 V and 0.63 V in acid and neutral electrolytes,respectively,indicating the efficient pH-universal ORR performances.The assembled zinc-air battery using the PT-MnN4 SACs as air cathodes exhibits a high peak power density(175 mW cm^(−2))and long-term stability up to 150 h,implying its promising application in metal-air batteries.This study has paved the way toward the rational design and precise regulation of single-atom electrocatalysts.
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financially supported by the National Natural Science Foundation of China(Nos.21725103,52072362)National Key R&D Program of China(No.2021YFB4000401)Youth Innovation Promotion Association CAS(No.E1202002)。
文摘Electrochemical is considered an attractive approach to recycling the pollution NO(NORR)and producing the valuable NH_(3),which could simultaneously solve the two challenging problems,i.e.,NO removal and NH_(3)synthesis.Current research efforts focus less on NORR due to the lack of effective catalysts.Herein,based on DFT calculation,we try to explore effective pyrrole-type TM-N_(4)(TM=V,Cr,Mn,Fe,Co,Ni,Cu,Ru,Rh,Ta)catalysts for achieving the direct NORR.Among the investigated systems,Fe-N_(4)exhibits excellent catalytic activity and high NH_(3)selectivity.Moreover,the free energy of adsorption of N*has been proposed as a descriptor to predict and screen the effective TM-N_(4)catalyst for NORR and the crystal orbital halmilton populations(COHP)is used to describe the intrinsic relationship between metal atoms and the adsorption free energy of N^(*)intermediate.This work has provided a theoretical picture of TM-N4catalyzing NO to NH_(3),which will establish guidelines for the rational design of NORR catalysts and other electrochemical reactions.
基金This work was supported by 973 Program of the MOST (001CB108906), the National Natural Science Foundation of China (90206040, 20073048, 20333070, and 20303021), and the NSF of Fujian Province (2002F015 and 2002J006) and the Chinese Academy of Sciences
文摘The complex [Cu（C5H7O2）（C5H8N2）3]Br·C2H5OH was obtained from a reaction of CuBr, acac, and Hdmpz （Hdmpz=3, 5-dimethylpyrazole） in a mixed solution of ethanol, ether and water. The crystal belongs to monoclinic system, space group P21/n with a=8.101（5）, b=19.264 （10）, c=17.19（3）A°, β=95.54（2）°, V=2670（5） A°3, Z=4, Mr=577.03, Dc=1.435 g/cm^3, F（000）=1196,μ=2.348 mm^-1, R=0.0500 and wR=0.1188 for 5361 observed reflections （1〉2σ（I））. The Cu（Ⅱ） ion is coordinated by three Hdmpz and one acac to form a distorted square-pyramid. The complex contains an ethanol molecule and a bromide anion outside acting as the counter ion.
