Integrating Amorphous Molybdenum Sulfide Nanosheets with a Co<sub>9</sub>S<sub>8</sub>@Ni<sub>3</sub>S<sub>2</sub> Array as an Efficient Electrocatalyst for Overall Water Splitting
Caihong Feng, Qingze Jiao, Jiatao Zhang, Huiru Cui, Hansheng Li, Yun Zhao, Caihong Feng
Abstract
It is highly challenging to design low-cost, efficient electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, a hierarchical heterostructure was constructed on three-dimensional (3D) Ni foam, which contains Ni3S2 nanorods decorated with both Co9S8 and amorphous MoSx nanosheets and Ni3S2 nanowires decorated with amorphous MoSx nanosheets, namely, MoSx@Co9S8@Ni3S2/NF. The synergistic effects from the strong interactions of the heterointerface and unique hierarchical heterostructure endow the MoSx@Co9S8@Ni3S2/NF with abundant active sites and effective mass and electron transport pathways, resulting in excellent activity toward both HER and OER in 1 M KOH. It only gives a low overpotential of 76.5 mV to achieve 10 mA cm–2 for HER and a low overpotential of 310 mV to achieve 100 mA cm–2 for OER. Based on the superior catalytic activity of MoSx@Co9S8@Ni3S2/NF for OER and HER, we demonstrated the activity of overall water splitting using MoSx@Co9S8@Ni3S2/NF as both the anode and cathode. It shows a higher catalytic activity for overall water splitting with a low cell voltage of 1.52 V at 10 mA cm–2 than commercial Pt/C/NF||IrO2/NF (1.61 V) and superior stability. This work provides a platform for the design and preparation of efficient electrocatalysts with various hierarchical heterostructures.