A Facile Strategy to Create Electrocatalysts of Highly Dispersive Ni-Mo Sulfide Nanosheets on Graphene by Derivation of Polyoxometalate Coordination Polymer for Advanced H2 Evolution

Efficient hydrogen evolution reaction (HER) is a promising approach for large-scale hydrogen production. Nevertheless, exploring a nonprecious, ecofriendly, and high-activity electrocatalyst for the HER in alkaline media is still a challenging endeavor. In this work, a polyoxometalate (POM)-based crystalline polymer, {(trz)(3)Ni-2 center dot 6H(2)O}[H3GeMo12O40]center dot 9H(2)O (trz = 1,2,4-triazole), is prefabricated, and then it is converted to Ni-Mo-S-rGO-200-24-2 composite under additional thiourea and graphene oxide (GO) by a hydrothermal method for the first time. Our work proves that it is feasible to take advantage of the synergistic effects among Ni3S2, MoS2, and reduced graphene oxide (rGO) to enhance the electrocatalytic HER activity and durability in KOH electrolyte. Namely, Ni-Mo-S-rGO-200-24-2 shows a low overpotential of 118 mV@10 mA.cm(-2) vs the reversible hydrogen electrode (RHE) and remains stable for 20 h. Judging from the overall catalytic performance, we can conclude that Ni-Mo-S-rGO-200-24-2 electrocatalyst is one of the best non-noble HER catalysts reported to date.

Automated summary

In this study, a polyoxometalate-based crystalline polymer was used to prepare Ni-Mo-S-rGO-200-24-2 composite, which showed excellent HER activity and stability in KOH electrolyte. The synergistic effects among Ni3S2, MoS2, and rGO contributed to the enhanced electrocatalytic performance.