Yang Mingliang, Jin Hua, Song Jianfeng, She Shiqian, Chen Jia, Xiong Kun
Engineering Research Center for Waste Oil Recovery Technology and Equipment, Ministry of Education, College of Environment and Resources, Chongqing Technology and Business University, No. 19 Xuefu Avenue, Chongqing 400067, China.
J Chem Phys. 2025 Jul 28;163(4). doi: 10.1063/5.0279752.
Hydrogen production from water electrolysis is mainly affected by the high overpotential and slow reaction kinetics of the anodic oxygen evolution reaction (OER). Replacing slow oxygen evolution reaction (OER) with thermodynamically favorable urea oxidation reaction (UOR) is one of the feasible strategies for achieving energy-saving hydrogen production. In this work, a cactus-like nickel sulfide-lanthanum carbonate hydroxide (NiSx-LaCH) composite was synthesized on the surface of Ni foam by a hydrothermal method and sulfurization process for the first time. This cactus-like structure can significantly improve the specific surface area of the catalyst and the electrolyte accessibility. The coupling of NiSx and LaCH brought about the electron structure redistribution and enhanced the stability and conductivity. The generated synergistic effect of NiSx-LaCH/NF improved the adsorption of urea/water molecules and the intrinsic catalytic activity. It exhibited outstanding electrocatalytic performance for UOR and hydrogen evolution reaction, which can drive the current density of 100 mA cm-2 at low potentials of 1.36 V and -0.26 V, respectively. Assembling NiSx-LaCH/NF into urea electrolysis system can reduce the cell voltage by 0.22 V compared to water electrolysis. This indicates that using UOR instead of OER could achieve energy-saving hydrogen production and has promising prospects in treating urea-rich wastewater.
水电解制氢主要受阳极析氧反应（OER）的高过电位和缓慢反应动力学的影响。用热力学有利的尿素氧化反应（UOR）取代缓慢的析氧反应（OER）是实现节能制氢的可行策略之一。在这项工作中，首次通过水热法和硫化工艺在泡沫镍表面合成了仙人掌状硫化镍-碳酸镧氢氧化物（NiSx-LaCH）复合材料。这种仙人掌状结构可以显著提高催化剂的比表面积和电解质可及性。NiSx和LaCH的耦合导致电子结构重新分布，增强了稳定性和导电性。NiSx-LaCH/NF产生的协同效应改善了尿素/水分子的吸附和本征催化活性。它对UOR和析氢反应表现出优异的电催化性能，分别在1.36 V和-0.26 V的低电位下驱动100 mA cm-2的电流密度。与水电解相比，将NiSx-LaCH/NF组装到尿素电解系统中可使电池电压降低0.22 V。这表明使用UOR代替OER可以实现节能制氢，并且在处理富含尿素的废水方面具有广阔的前景。
