(003)-Facet-Exposed Ni3S2 Nanoporous Thin Films on Nickel Foil for Efficient Water Splitting

Jing Dong, Fu-Qiang Zhang, Yang Yang, Yue-Biao Zhang, Hailong He, Xiaofeng Huang, Xiujun Fan,* and Xian-Ming Zhang*
Appl. Catal. B: Environ. 2019243, 694–703
Developing earth-abundant catalysts for overall water splitting is important to sustainable energy conversion technologies. However, selectively exposing active surface and judiciously optimizing nanostructure remain challenging for high-performance electrocatalysts. Herein, (003)-facet-exposed Ni3S2 nanoporous thin films (NTFs) on nickel foil are synthesized through anodization and vapor-sulfurization strategies. The Ni3S2 NTFs exhibit low onset overpotentials of 48 and 152 mV, and require overpotentials of 135 and 175 mV to achieve a benchmark of 10 mA cm–2 towards alkaline hydrogen and oxygen evolution, respectively. Remarkably, an electrolyzer assembled by Ni3S2 NTFs as both anode and cathode can deliver a water-splitting current density of 10 mA cm–2 at 1.611 V. Experimental and theoretical results indicate that the controllable hollow nanoporous spheres and low-coordinated Ni3-triangles on Ni3S2(003) facet synergistically contribute to the electrocatalytic activity.