N, S Co-Coordinated Mo Defect Sites in Metal Coordination Polymers for Boosting Perdurable and High-Efficiency Alkaline Hydrogen Evolution

Abstract

In the area of water electrolysis, molybdenum sulfide (MoSx) materials have attracted a lot of interest and investigation due to their platinum-like catalytic activity. Herein, this work describes the synthesis of a novel molybdenum-based coordination metal polymer (CMP) by adding s-triazine-2,4,6-trithiol (C3H3N3S3) ligands under mild conditions, which addresses the issues of poor electrical conductivity and limited exposure of active sites in conventional MoSx materials. Combination of X-ray absorption near-edge spectroscopy, X-ray photoelectron spectroscopy, and in situ Raman spectroscopy identifies the key role of N, S co-coordinated Mo defect site [MoV(═O)SxNy] moieties as active sites in alkaline hydrogen evolution reaction (HER) processes. Benefitting from the good electrical conductivity of the CMP network, the efficient dispersion, and anchoring of the oxygenated molybdenum sites by N and S, the optimized Mo-based CMP exhibits a high-efficiency alkaline HER (η10: 87 mV) with 30,000 CV times cycle stability. This good HER catalyst also shows well durability at 100 mA cm–2 for 80 h in alkaline simulated seawater (1 M KOH + 0.5 M NaCl). This work inspires new ideas to design N, S co-coordinated molybdenum-based CMP electrocatalysts for hydrogen production by commercial alkaline water splitting.