Silverton-type polyoxometalate-derived electrocatalyst for efficient hydrogen evolution in acidic and alkaline media

Highly efficient and durable nonnoble-metal electrocatalysts for the hydrogen evolution reaction (HER) are essential for large-scale green hydrogen production. In this work, a trimetallic polyoxometalate precursor, H₂[Co(NH₃)₆]₂[CeMo₁₂O₄₂], was synthesized via polyoxometalate self-assembly. Subsequently, a Co,Ce-codoped MoS₂ electrocatalyst (Co,Ce-MoS₂@CC) was grown in situ on carbon cloth (CC) through one-step hydrothermal sulfidation. This precursor strategy effectively avoids phase separation and interfacial mismatch—the two major drawbacks of conventional doping routes. Experimental results combined with density functional theory calculations revealed that Ce³⁺/Ce⁴⁺ redox pairs modulate the interfacial charge distribution in the catalyst. Doped Co species serve as electron acceptors to counterbalance the electron enrichment induced by Ce, optimizing HER kinetics and the adsorption/desorption free energies of reaction intermediates. In 1.0 M KOH, the optimized Co,Ce-MoS₂@CC requires an overpotential of only 58 mV to deliver 10 mA·cm⁻, and 118 mV in 0.5 M H₂SO₄. It maintains stable performance over 72 h at a current density of 100 mA·cm⁻² in both alkaline and acidic electrolytes. This work proposes a polyoxometalate precursor-mediated Co,Ce-codoping strategy, offering a promising route for the scalable fabrication of high-performance, nonnoble-metal MoS₂ electrocatalysts for the HER.