Dual-Functional Starfish-like P-Doped Co-Ni-S Nanosheets Supported on Nickel Foams with Enhanced Electrochemical Performance and Excellent Stability for Overall Water Splitting.
Dual-Functional Starfish-like P-Doped Co-Ni-S Nanosheets Supported on Nickel Foams with Enhanced Electrochemical Performance and Excellent Stability for Overall Water Splitting.
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DOI：
10.1021/acsami.7b18403
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发表时间：
2018-02
影响因子：
9.5
通讯作者：
Fangfang Zhang;Yuancai Ge;Hang Chu;Pei Dong;Robert Baines;Yu Pei;M. Ye;Jianfeng Shen
中科院分区：
文献类型：
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作者：
Fangfang Zhang;Yuancai Ge;Hang Chu;Pei Dong;Robert Baines;Yu Pei;M. Ye;Jianfeng Shen
最近有报道称，双功能电催化剂可以改善碱性电解液中水分解产生的能量的转化和存储。本论文首次采用一步水热法在三维(3D)多孔泡沫镍(Co-Ni-S/NF)上制备了海星状Co-Ni-S纳米薄片。研究了反应时间对纳米片结构和性能的影响。反应11h后，Co-Ni-S/NF-11样品呈现出最规则的纳米片状结构和最优异的电化学性能。对于水的分解，析氢反应和析氧反应分别需要284.3 mV和296 mV的过电位才能提供100 mA cm-2的电流密度。这种出色的电化学性能可以归因于三维层状多孔镍骨架的导电网络，这些骨架高度互连，提供了较大的比表面积和高活性中心。为了进一步提高电催化剂的电化学性能，还研究了P元素的掺杂对电催化剂性能的影响。结果表明，P掺杂的Co-Ni-S/Nf保持了海星结构，具有优异的性能，其电流密度为100mA cm-2，过电位仅为187.4 mV和292.2 mV。它表现出比已报道的双功能电催化剂更优异的性能。此外，当用作整体裂水催化剂时，P-Co-Ni-S/NF在给定的电池电压1.60V的1MKOH中可以提供10 mA cm-2的电流密度，这与最著名的电催化剂相竞争，具有很高的长期稳定性。
Dual-functional electrocatalysts have recently been reported to improve the conversion and storage of energy generated from overall water splitting in alkaline electrolytes. Herein, for the first time, a shape-controlled synthesis of starfish-like Co-Ni-S nanosheets on three-dimensional (3D) hierarchically porous nickel foams (Co-Ni-S/NF) via a one-step hydrothermal method was developed. The influence of reaction time on the nanosheet structure and properties was intensively studied. After 11 h reaction, the Co-Ni-S/NF-11 sample displays the most regular structure of nanosheets and the most outstanding electrochemical properties. As to water splitting, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) required overpotentials of 284.3 and 296 mV, respectively, to provide a current density of 100 mA cm-2. The marvelous electrochemical performance can be attributed to the conductive networks of 3D layered porous nickel skeletons that are highly interconnected, which provided a large specific area and highly active sites. To further enhance the electrochemical performances of the electrocatalyst, the influence of the doping of the P element was also studied. The results proved that the P-doped Co-Ni-S/NF maintains the starfish structure and demonstrates outstanding properties, providing a current density of 100 mA cm-2 with only 187.4 and 292.2 mV overpotentials for HER and OER, respectively. It exhibited far more excellent properties than reported dual-functional electrocatalysts. Additionally, when used as an overall water-splitting catalyst, P-Co-Ni-S/NF can provide a 10 mA cm-2 current density at a given cell voltage of 1.60 V in 1 M KOH, which is competitive to the best-known electrocatalysts, with high long-term stability.