In the present work, nitrogen‐doped carbon spheres were synthesized through a simple hydro‐thermal treatment using glucose and melamine as inexpensive carbon and nitrogen sources, re‐spectively. The ratio of melami...In the present work, nitrogen‐doped carbon spheres were synthesized through a simple hydro‐thermal treatment using glucose and melamine as inexpensive carbon and nitrogen sources, re‐spectively. The ratio of melamine to glucose and annealing temperature were optimized. The final optimal sample exhibited a catalytic activity for the oxygen reduction reaction（ORR） that was supe‐rior than that of commercial 20%Pt/C in 0.1 mol/L KOH. It revealed an onset potential of –22.6 mV and a half‐wave potential of –133.6 mV （vs. Ag/AgCl）, which are 7.2 and 5.9 mV more positive than those of the 20%Pt/C catalyst, respectively, as well as a limiting current density of 4.6 mA/cm^2, which is 0.2 mA/cm^2 higher than that of the 20%Pt/C catalyst. The catalyst also exhibited higher stability and superior durability against methanol than 20%Pt/C. Moreover, ORRs on this catalyst proceed through a more effective 4 e^– path. The above mentioned superiority of the as‐prepared catalyst makes it promising for fuel cells.展开更多
Metal doping for active sites exhibits remarkable potential for improving the hydrogen evolution reaction(HER).Multi-doping and the use of a conductive substrate can further modulate catalytic performance.Herein,Nb-Co...Metal doping for active sites exhibits remarkable potential for improving the hydrogen evolution reaction(HER).Multi-doping and the use of a conductive substrate can further modulate catalytic performance.Herein,Nb-CoSe well dispersed in N-doped carbon nanospheres(NCs,Nb-CoSe@NC)was synthesized to serve as a conductive substrate and facilitated good dispersion of active sites for the HER.Nb doping can also change the electronic structure of CoSe,which facilitates the activity for the HER.In order to further improve the conductivity and intrinsic activity of Nb-CoSe@NC,dual,nonmetal doping was realized through gas sulfurization to prepare hierarchical Nb-CoSeS@NC.The prepared Nb-CoSeS@NC,with a core-shell structure,exhibited a low overpotential of 115 mV at 10 mA cm–2,which is smaller than that of the most doped catalysts.In addition,NCs not only improved the dispersion and conductivity of the catalyst but also prevented metal corrosion in an electrolyte,thus facilitating the long-term stability of Nb-CoSeS@NC.Moreover,the synergistic effect of the multi-doping of Nb,S,and Se was explained.This work provides a promising,multi-doping strategy for the large-scale application of transition-metal-based electrocatalysts for the HER.展开更多
Here we report a new approach referred as ＂soft- to-hard templating＂ strategy via the copolymerization of carbon source （dopamine） and silica source （tetraethyl orthosilicate） for the synthesis of well dispersed...Here we report a new approach referred as ＂soft- to-hard templating＂ strategy via the copolymerization of carbon source （dopamine） and silica source （tetraethyl orthosilicate） for the synthesis of well dispersed N-doped mesoporous carbon nanospheres （MCNs）, which exhibit high performance for electrochemical supercapacitor. This method overcomes the shortcoming of uncontrolled dis- persity and complicated procedures of soft- or hard-tem- plating methods, respectively. Moreover, the synthesized MCNs feature enriched heteroatom N-doping and easy functionalization by noble-metal nanoparticles during the one-pot synthesis. All the above characters make the as- prepared MCNs a promising platform in a variety of applications. To demonstrate the applicability of the syn- thesized nitrogen-doped MCNs, this material has been employed as an electrode for high-performance electro- chemical supercapacitor, which shows a capacitance of 223 and 140 F/g at current densities of 0.5 and 10 A/g in 1 mol/L KOH electrolyte, respectively.展开更多
Encompassing ecological and economic concerns, the utilization of biomass to produce carbonaceous materials has attracted intensive research and industrial interest. Using nitrogen containing precursors could realize ...Encompassing ecological and economic concerns, the utilization of biomass to produce carbonaceous materials has attracted intensive research and industrial interest. Using nitrogen containing precursors could realize an in situ and homogeneous incorporation of nitrogen into the carbonaceous materials with a controlled process. Herein, N-doped hollow core-disordered mesoporous shell carbonaceous nanospheres （HCDMSs） were synthesized from glucosamine hydrochloride （GAH）, an applicable carbohydrate-based derivative. The obtained HCDMSs possessed controlled size （-450-50 nm） and shell thickness （-70-10 nm）, suitable nitrogen contents （-6.7-4.4 wt.%）, and Brunauer-Emmett-Teller （BET） surface areas up to 770 m^2.g^-1. These materials show excellent electrocatalytic activity as a metal-free catalyst for the oxygen reduction reaction （ORR） in both alkaline and acidic media. Specifically, the prepared HCDMS-1 exhibits a high diffusion-limited current, and superior durability and better immunity towards methanol crossover and CO poisoning for ORR in alkaline solution than a commercial 20 wt.% Pt/C catalyst.展开更多
基金supported by National Natural Science Foundation of China(22108306)Taishan Scholars Program of Shandong Province(tsqn201909065)Shandong Provincial Natural Science Foundation(ZR2021YQ15,ZR2020QB174)。
文摘In the present work, nitrogen‐doped carbon spheres were synthesized through a simple hydro‐thermal treatment using glucose and melamine as inexpensive carbon and nitrogen sources, re‐spectively. The ratio of melamine to glucose and annealing temperature were optimized. The final optimal sample exhibited a catalytic activity for the oxygen reduction reaction（ORR） that was supe‐rior than that of commercial 20%Pt/C in 0.1 mol/L KOH. It revealed an onset potential of –22.6 mV and a half‐wave potential of –133.6 mV （vs. Ag/AgCl）, which are 7.2 and 5.9 mV more positive than those of the 20%Pt/C catalyst, respectively, as well as a limiting current density of 4.6 mA/cm^2, which is 0.2 mA/cm^2 higher than that of the 20%Pt/C catalyst. The catalyst also exhibited higher stability and superior durability against methanol than 20%Pt/C. Moreover, ORRs on this catalyst proceed through a more effective 4 e^– path. The above mentioned superiority of the as‐prepared catalyst makes it promising for fuel cells.
文摘Metal doping for active sites exhibits remarkable potential for improving the hydrogen evolution reaction(HER).Multi-doping and the use of a conductive substrate can further modulate catalytic performance.Herein,Nb-CoSe well dispersed in N-doped carbon nanospheres(NCs,Nb-CoSe@NC)was synthesized to serve as a conductive substrate and facilitated good dispersion of active sites for the HER.Nb doping can also change the electronic structure of CoSe,which facilitates the activity for the HER.In order to further improve the conductivity and intrinsic activity of Nb-CoSe@NC,dual,nonmetal doping was realized through gas sulfurization to prepare hierarchical Nb-CoSeS@NC.The prepared Nb-CoSeS@NC,with a core-shell structure,exhibited a low overpotential of 115 mV at 10 mA cm–2,which is smaller than that of the most doped catalysts.In addition,NCs not only improved the dispersion and conductivity of the catalyst but also prevented metal corrosion in an electrolyte,thus facilitating the long-term stability of Nb-CoSeS@NC.Moreover,the synergistic effect of the multi-doping of Nb,S,and Se was explained.This work provides a promising,multi-doping strategy for the large-scale application of transition-metal-based electrocatalysts for the HER.
基金This work was supported by the National Basic Research Program of China （2013CB933200）, the National High Technology Research and Development Program of China （2012AA062703）, the National Natural Science Foundation of China （21177137） and the Youth Innovation Promotion Association CAS （2012200）.
文摘Here we report a new approach referred as ＂soft- to-hard templating＂ strategy via the copolymerization of carbon source （dopamine） and silica source （tetraethyl orthosilicate） for the synthesis of well dispersed N-doped mesoporous carbon nanospheres （MCNs）, which exhibit high performance for electrochemical supercapacitor. This method overcomes the shortcoming of uncontrolled dis- persity and complicated procedures of soft- or hard-tem- plating methods, respectively. Moreover, the synthesized MCNs feature enriched heteroatom N-doping and easy functionalization by noble-metal nanoparticles during the one-pot synthesis. All the above characters make the as- prepared MCNs a promising platform in a variety of applications. To demonstrate the applicability of the syn- thesized nitrogen-doped MCNs, this material has been employed as an electrode for high-performance electro- chemical supercapacitor, which shows a capacitance of 223 and 140 F/g at current densities of 0.5 and 10 A/g in 1 mol/L KOH electrolyte, respectively.
基金Financial support from the National Natural Science Foundation of China （Ul162124 ＆ 21376208）, the Zhejiang Provincial Natural Science Foundation for Distinguished Young Scholars of China （LR13B030001）, the Specialized Research Fund for the Doctoral Program of Higher Education （J20130060）, the Fun- damental Research Funds for the Central Universities, the Program for Zhejiang Leading Team of S＆T Innovation, the Partner Group Program of the Zhejiang University and the Max-Planck Society are greatly appreciated.
文摘Encompassing ecological and economic concerns, the utilization of biomass to produce carbonaceous materials has attracted intensive research and industrial interest. Using nitrogen containing precursors could realize an in situ and homogeneous incorporation of nitrogen into the carbonaceous materials with a controlled process. Herein, N-doped hollow core-disordered mesoporous shell carbonaceous nanospheres （HCDMSs） were synthesized from glucosamine hydrochloride （GAH）, an applicable carbohydrate-based derivative. The obtained HCDMSs possessed controlled size （-450-50 nm） and shell thickness （-70-10 nm）, suitable nitrogen contents （-6.7-4.4 wt.%）, and Brunauer-Emmett-Teller （BET） surface areas up to 770 m^2.g^-1. These materials show excellent electrocatalytic activity as a metal-free catalyst for the oxygen reduction reaction （ORR） in both alkaline and acidic media. Specifically, the prepared HCDMS-1 exhibits a high diffusion-limited current, and superior durability and better immunity towards methanol crossover and CO poisoning for ORR in alkaline solution than a commercial 20 wt.% Pt/C catalyst.
