Zhang Lili, Zhang Tingting, Dai Kaiqing, Zhao Liqing, Wei Qinghe, Zhang Bing, Xiang Xu
School of Chemical Engineering, Zhengzhou University Zhengzhou 450001 P. R. China.
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology 15 Beisanhuan East Road Beijing 100029 PR China
RSC Adv. 2020 Aug 11;10(49):29326-29335. doi: 10.1039/d0ra05950a. eCollection 2020 Aug 5.
The development of bifunctional electrocatalysts based on highly efficient non-noble metals is pivotal for overall water splitting. Here, a composite electrode of CoO@CoWP is synthesized, where an ultrathin layer composed of CoO nanoparticles is grown on CoWP nanowires supported on a carbon cloth (CC). The CoO@CoWP/CC electrode exhibits excellent electrocatalytic activity and improved kinetics towards both the oxygen and hydrogen evolution reactions (OER and HER). The CoO@CoWP/CC electrode achieves a current density of 10 mA cm at a low overpotential of 269 mV for the OER and -10 mA cm at 118 mV for the HER in 1.0 M KOH solution. The voltage applied to a two-electrode water electrolyzer for overall water splitting, while employing the CoO@CoWP/CC electrode as both an anode and a cathode, in order to reach a current density of 10 mA cm, is 1.61 V, which is better than that for the majority of reported non-noble electrocatalysts. Moreover, the CoO@CoWP/CC electrode exhibits good stability over 24 h with slight attenuation. The electrode benefits from the enhanced adsorption of oxygen intermediates on CoO during the OER, the increased ability for water dissociation and the optimized H adsorption/desorption ability of CoWP nanowires during the HER. This study provides a feasible approach for cost-effective and high-performance non-noble metal bifunctional catalysts for overall water electrolysis.
基于高效非贵金属的双功能电催化剂的开发对于整体水分解至关重要。在此，合成了CoO@CoWP复合电极，其中由CoO纳米颗粒组成的超薄层生长在支撑于碳布（CC）上的CoWP纳米线上。CoO@CoWP/CC电极对析氧反应和析氢反应（OER和HER）均表现出优异的电催化活性和改善的动力学。在1.0 M KOH溶液中，CoO@CoWP/CC电极在269 mV的低过电位下实现了10 mA cm的析氧电流密度，在118 mV下实现了-10 mA cm的析氢电流密度。在使用CoO@CoWP/CC电极作为阳极和阴极的情况下，为了达到10 mA cm的电流密度，施加于两电极水电解槽进行整体水分解的电压为1.61 V，这优于大多数已报道的非贵金属电催化剂。此外，CoO@CoWP/CC电极在24 h内表现出良好的稳定性，仅有轻微衰减。该电极得益于在OER过程中CoO上氧中间体吸附的增强、水离解能力的提高以及在HER过程中CoWP纳米线对H吸附/脱附能力的优化。本研究为用于整体水电解的具有成本效益和高性能的非贵金属双功能催化剂提供了一种可行的方法。
