Liu Suli, Che Chenjing, Jing Haiyan, Zhao Jun, Mu Xueqin, Zhang Sudi, Chen Changyun, Mu Shichun
Key Laboratory of Advanced Functional Materials of Nanjing, Nanjing Xiaozhuang University, Nanjing 211171, China.
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.
Nanoscale. 2020 Feb 7;12(5):3129-3134. doi: 10.1039/c9nr09203j. Epub 2020 Jan 22.
Introduction of surface defects and phase control engineering in the electrocatalytic system of overall water splitting has played a crucial role in significantly enhancing its electrocatalytic activity toward the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in water splitting, but the relationship between structure and electrocatalysis is still elusive. Herein, we report a solid-liquid method to induce surface reorganization (formation of a chalcogenide layer with rich chalcogenide vacancies) and phase transformation (CoS-to-CoS) simultaneously on cobalt chalcogenide. Featuring a uniform 2D morphology and the in situ formation of sulfur (S) vacancies, in a 0.1 M KOH solution, it exhibits a low overpotential of 288 mV vs. RHE at 10 mA cm, a low Tafel slope of 43.4 mV dec, and strong cycling stability (35 h), outperforming commercial RuO and most reported OER electrocatalysts. In addition, we also investigate the OER activity of the Co-S-P electrode in 1.0 M KOH solutions. CoSP NSs only need 257 mV to reach a current density of 10 mA cm. Meanwhile, the Tafel slope of CoSP NSs (44.0 mV dec) is lower than those of other recently reported electrocatalysts. Also, it shows high HER electrocatalytic activity in alkaline and acidic solutions. Finally, the CoSP electrode is used as a cathode and anode simultaneously for overall water splitting, which merely requires a cell voltage of 1.59 V at 10 mA cm with excellent stability (40 h).
在全水解电催化体系中引入表面缺陷和相控工程在显著提高其对析氢反应（HER）和析氧反应（OER）的电催化活性方面发挥了关键作用，但结构与电催化之间的关系仍然难以捉摸。在此，我们报道了一种固液法，可在硫族钴化物上同时诱导表面重组（形成具有丰富硫族化物空位的硫族化物层）和相变（CoS 到 CoS）。其具有均匀的二维形态和原位形成的硫（S）空位，在 0.1 M KOH 溶液中，在 10 mA cm 时相对于可逆氢电极（RHE）表现出 288 mV 的低过电位、43.4 mV dec 的低塔菲尔斜率以及强循环稳定性（35 h），性能优于商业 RuO 和大多数已报道的 OER 电催化剂。此外，我们还研究了 Co-S-P 电极在 1.0 M KOH 溶液中的 OER 活性。CoSP 纳米片仅需 257 mV 即可达到 10 mA cm 的电流密度。同时，CoSP 纳米片的塔菲尔斜率（44.0 mV dec）低于其他最近报道的电催化剂。此外，它在碱性和酸性溶液中均表现出高 HER 电催化活性。最后，CoSP 电极同时用作全水解的阴极和阳极，在 10 mA cm 时仅需 1.59 V 的电池电压且具有出色的稳定性（40 h）。
