Porous metallic MoO2-supported MoS2 nanosheets for enhanced electrocatalytic activity in the hydrogen evolution reaction

Abstract

Advanced materials for electrocatalytic water splitting are central to renewable energy research. In this work, MoS₂ nanosheets supported on porous metallic MoO₂ (MoS₂/MoO₂) were produced by sulfuration treatments of porous and highly conductive MoO₂ for the hydrogen evolution reaction. Porous MoO₂ with one-dimensional channel-like structures was prepared by calcination at elevated temperatures using phosphomolybdic acid as the precursor and mesoporous silica (SBA-15) as the template, and the subsequent hydrothermal treatment in the presence of thioacetamide led to the transformation of the top layers to MoS₂ forming MoS₂/MoO₂ composites. Electrochemical studies showed that the obtained composites exhibited excellent electrocatalytic activity for HER with an onset potential of −104 mV (vs. RHE), a large current density (10 mA cm⁻² at −0.24 V), a small Tafel slope of 76.1 mV dec⁻¹ and robust electrochemical durability. The performance might be ascribed to the high electrical conductivity and porous structures of MoO₂ with one-dimensional channels of 3 to 4 nm in diameter that allowed for fast charge transport and collection.