Tian Yifan, Xue Xinying, Gu Yu, Yang Zhaoxi, Hong Guo, Wang Chundong
School of Optical and Electronic Information, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
Nanoscale. 2020 Nov 26;12(45):23125-23133. doi: 10.1039/d0nr07227c.
Electrochemically splitting water into hydrogen and oxygen plays a significant role in the commercialization of hydrogen energy as well as fuel cells, but it remains a challenge to design and fabricate low-cost and high-efficiency electrocatalysts. Herein, we successfully prepared Ni3Se2/MoSex on nickel foam via a facile electrodeposition method. To understand the electrochemical mechanism occurring in the electrodeposition process, a new model was proposed, providing insight into the nucleation and growth of deposited materials. The as-prepared Ni3Se2/MoSex exhibits splendid electrochemical performance with 82 mV and 270 mV overpotentials to drive a current density of 10 mA cm-2 in 1 M KOH aqueous solution for HER and OER, respectively. Moreover, a driving potential of 1.57 V is required to reach a current density of 10 mA cm-2 for a configured full cell with Ni3Se2/MoSex working as both the anode and cathode towards overall water splitting, outperforming the state-of-the-art commercial full cells assembled with noble-based metals. The advanced catalytic performance should be attributed to the numerous in situ formed interfaces, allowing π-electron transfer from Ni to Mo via O2- bridging, subsequently optimizing the adsorption features of oxygenated species (OER) and favorable Volmer/Heyrovsky reaction (HER). This work offers an effective and scalable fabrication prototype for the preparation of bifunctional electrocatalysts with electrodeposition.
将水电化学分解为氢气和氧气在氢能商业化以及燃料电池中发挥着重要作用，但设计和制造低成本、高效率的电催化剂仍然是一个挑战。在此，我们通过一种简便的电沉积方法成功地在泡沫镍上制备了Ni3Se2/MoSex。为了理解电沉积过程中发生的电化学机制，提出了一个新模型，深入了解了沉积材料的成核和生长过程。所制备的Ni3Se2/MoSex在1 M KOH水溶液中驱动10 mA cm-2的电流密度时，HER和OER的过电位分别为82 mV和270 mV，表现出优异的电化学性能。此外，对于一个以Ni3Se2/MoSex作为阳极和阴极用于全水分解的配置全电池，达到10 mA cm-2的电流密度需要1.57 V的驱动电位，优于用贵金属组装的现有商业全电池。这种优异的催化性能应归因于大量原位形成的界面，允许π电子通过O2-桥从Ni转移到Mo，随后优化了含氧物种的吸附特性（OER）以及有利的Volmer/Heyrovsky反应（HER）。这项工作为通过电沉积制备双功能电催化剂提供了一种有效且可扩展的制造原型。
