Lattice-controllable in-situ synthesis of Co-Ni-mixed sulfide/polypyrrole nanostructures on carbon paper for hydrogen evolution reaction in alkaline media

Developing high-performance and low-cost electrocatalysts for the hydrogen evolution reaction (HER) fa-vorably promotes large-scale hydrogen production from water. Here, we design a nanocomposite of Co9S8- Ni9S8 nanodiscs (CNS) in-situ grown from polypyrrole hollow nanospheres (PHS) on carbon paper (CP) via unipolar pulse electrodeposition (UPED) technique as HER catalyst in alkaline media. The lattice structure along with the interlacing nanodiscs-like morphology of the Co9S8-Ni9S8 mischcrystal is controllable by UPED method. The optimal CNS/PHS/CP electrode obtained with pulse potential of - 0.80 V exhibits fa-vorable catalytic activity with low overpotential (186 mV at 10 mA cm-2), superior stability performance (for 100 h with no current density decay), and high electrochemically active surface area up to 1925 cm2, which should be attributed to the interlacing Co9S8-Ni9S8 mischcrystal with rich active sites, the ingenious combination with conductive polymer, and the integrated electron-proton conductive network. This work will provide a new sight to design low-cost bimetallic sulfide-based electrocatalysts for high-performance HER in water splitting. & COPY; 2023 Elsevier B.V. All rights reserved.