Mesoporous Molybdenum Sulfide-Oxide Composite Thin-Film Electrodes Prepared by a Soft Templating Method for the Hydrogen Evolution Reaction

Abstract

Electrode designs involving binder-free nanoparticles integrated within interconnected pore networks are critical in scaling up electrolyzers. MoS2is the most promising electrocatalyst candidate that can show hydrogen evolution reaction (HER) activity comparable to platinum (Pt). Herein, a facile one-step soft templating method was developed to synthesize mesoporous molybdenum sulfide-oxide composite thin-film electrocatalysts directly on any substrate without using a binder or a template. Fabricated electrocatalysts contain amorphous MoS3and small crystallite-sized MoS2embedded into amorphous MoO3with a large surface area (around 182 m2/g). The electrocatalyst layer undergoes in situ electrochemical activation in which amorphous MoS3is reduced to MoS2during the HER in acidic media. The electrocatalyst layer on the carbon fiber exhibits a low overpotential (∼189 mV at 10 mA/cm2) and Tafel slope (53 mV/dec) toward the HER after electrochemical activation.