Developing efficient metal-free bi-functional electrocatalysts is required to reduce costs and improve the slow oxygen reduction reaction （ORR） and oxygen evo- lution reaction （OER） kinetics in electrochemical sys...Developing efficient metal-free bi-functional electrocatalysts is required to reduce costs and improve the slow oxygen reduction reaction （ORR） and oxygen evo- lution reaction （OER） kinetics in electrochemical systems. Porous N-doped carbon nanotubes （NCNTs） were fabri- cated by KOH activation and pyrolysis of polypyrrole nanotubes. The NCNTs possessed a large surface area of more than 1,000 m2 g-1. NCNT electrocatalysts, particu- larly those annealed at 900 ℃, exhibited excellent ORR electrocatalytic performance. Specifically, they yielded a more positive onset potential, higher current density, and long-term operation stability in alkaline media, when compared with a commercially available 20 wt% Pt/C catalyst. This resulted from the synergetic effect between the dominant pyridinic/graphitic-N species and the porous tube structures. The NCNT electrocatalyst also exhibited good performance for the OER. The metal-free porous nitrogen-doped carbon nanomaterials were prepared from low cost and environmentally friendly precursors. They are potential alternatives to Pt/C catalysts, for electrochemical energy conversion and storage.展开更多
Developing high-performance bifunctional catalysts toward hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) is essential to enhance water splitting efficiency for large-scale hydrogen production. Nei...Developing high-performance bifunctional catalysts toward hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) is essential to enhance water splitting efficiency for large-scale hydrogen production. Neither noble metal Pt nor transition metal compounds show satisfactory performances for both HER and OER simultaneously. Here, we prepared a three-dimensional Pt-Ni3 Se2@NiOOH/NF(PNOF) hybrid catalyst via in-situ growth strategy. Benefitting from the self-supported structure and oxygen vacancies on the surface of NiOOH nanosheets, the PNOF electrode shows remarkably catalytic performance for dual HER and OER. The overall water electrolyzer using PNOF as anode and cathode can achieve a current density of10 mA cm^-2 at a low voltage of 1.52 V with excellent long-term stability, which is superior to precious metal catalysts of Pt/C and Ir/C. This study provides a promising strategy for preparing bifunctional catalysts with high performance.展开更多
基金This work was supported by the National Nat- ural Science Foundation of China （51273008, 51473008）, and the National Basic Research Program of China （2012CB933200）.
文摘Developing efficient metal-free bi-functional electrocatalysts is required to reduce costs and improve the slow oxygen reduction reaction （ORR） and oxygen evo- lution reaction （OER） kinetics in electrochemical systems. Porous N-doped carbon nanotubes （NCNTs） were fabri- cated by KOH activation and pyrolysis of polypyrrole nanotubes. The NCNTs possessed a large surface area of more than 1,000 m2 g-1. NCNT electrocatalysts, particu- larly those annealed at 900 ℃, exhibited excellent ORR electrocatalytic performance. Specifically, they yielded a more positive onset potential, higher current density, and long-term operation stability in alkaline media, when compared with a commercially available 20 wt% Pt/C catalyst. This resulted from the synergetic effect between the dominant pyridinic/graphitic-N species and the porous tube structures. The NCNT electrocatalyst also exhibited good performance for the OER. The metal-free porous nitrogen-doped carbon nanomaterials were prepared from low cost and environmentally friendly precursors. They are potential alternatives to Pt/C catalysts, for electrochemical energy conversion and storage.
基金supported by the National Natural Science Foundation of China(51804216,51472178 and U1601216)Tianjin Natural Science Foundation(16JCYBJC17600)and Shen-zhen Science and Technology Foundation(JCYJ20170307145703486)
文摘Developing high-performance bifunctional catalysts toward hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) is essential to enhance water splitting efficiency for large-scale hydrogen production. Neither noble metal Pt nor transition metal compounds show satisfactory performances for both HER and OER simultaneously. Here, we prepared a three-dimensional Pt-Ni3 Se2@NiOOH/NF(PNOF) hybrid catalyst via in-situ growth strategy. Benefitting from the self-supported structure and oxygen vacancies on the surface of NiOOH nanosheets, the PNOF electrode shows remarkably catalytic performance for dual HER and OER. The overall water electrolyzer using PNOF as anode and cathode can achieve a current density of10 mA cm^-2 at a low voltage of 1.52 V with excellent long-term stability, which is superior to precious metal catalysts of Pt/C and Ir/C. This study provides a promising strategy for preparing bifunctional catalysts with high performance.
