Qiao Xianshu, Kang Hongjun, Li Yang, Cui Kai, Jia Xin, Liu Henghao, Qin Wei, Pupucevski Max, Wu Gang
School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001, China.
School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001, China.
ACS Appl Mater Interfaces. 2020 Aug 12;12(32):36208-36219. doi: 10.1021/acsami.0c10024. Epub 2020 Aug 4.
We report a highly efficient and stable electrode composed of a porous Fe-doped β-nickel hydroxide nanopyramid array supported on nickel foam (U-Fe-β-Ni(OH)/NF) for overall water splitting. The unique structure is assembled via a self-templated strategy by utilizing the FeNi oxalate (FeNi-CO/NF) nanopyramid as the templates, followed by an anion-exchange reaction at room temperature. Due to the intrinsic activity of Fe-doped β-Ni(OH) along with unique porous array structures consisting of two-dimensional (2D) active materials on three-dimensional (3D) conductive substrates, the developed electrode exhibited outstanding electrocatalytic activity for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in an alkaline medium. The introduced amount of Fe plays a significant role in promoting OER and HER activity compared to the β-Ni(OH) electrode. The optimal electrode (U-Fe-β-Ni(OH)/NF-2) generated a current density of 10 mA cm at low overpotentials of 218 mV for the OER and 121 mV for the HER. The electrode also demonstrated considerably stable performance during the continuous water splitting process. Furthermore, we elucidated the promotion mechanisms of the active Fe-doped β-Ni(OH) compound for the OER and HER based on extensive characterization and electrochemical measurements. Hence, this work provides a facile approach to developing low-cost, efficient, and stable hydroxide-based electrodes for bifunctional OER and HER in water splitting.
我们报道了一种由负载在泡沫镍上的多孔铁掺杂β-氢氧化镍纳米金字塔阵列（U-Fe-β-Ni(OH)/NF）组成的用于全水分裂的高效稳定电极。通过利用草酸铁镍（FeNi-CO/NF）纳米金字塔作为模板，采用自模板策略组装独特结构，随后在室温下进行阴离子交换反应。由于铁掺杂β-Ni(OH)的固有活性以及由三维（3D）导电基底上的二维（2D）活性材料组成的独特多孔阵列结构，所制备的电极在碱性介质中对析氧反应（OER）和析氢反应（HER）均表现出优异的电催化活性。与β-Ni(OH)电极相比，引入的铁量在促进OER和HER活性方面起着重要作用。最佳电极（U-Fe-β-Ni(OH)/NF-2）在OER的低过电位为218 mV、HER的低过电位为121 mV时产生10 mA cm的电流密度。该电极在连续的水分裂过程中也表现出相当稳定的性能。此外，我们基于广泛的表征和电化学测量阐明了活性铁掺杂β-Ni(OH)化合物对OER和HER的促进机制。因此，这项工作为开发用于水分裂中双功能OER和HER的低成本、高效且稳定的氢氧化物基电极提供了一种简便方法。
