The synergistic benefits of hydrate CoMoO4 and carbon nanotubes culminate in the creation of highly efficient electrocatalysts for hydrogen evolution

Abstract

The electrochemical hydrogen evolution reaction (HER) stands as a burgeoning clean energy prospect. This work synthesized composite materials (CMOxCNT), exhibiting exceptional electrocatalytic prowess, emerged from the fusion of cobalt molybdate (CMO) and carbon nanotubes (CNT). The outcomes of characterization established the CMO as a hydrated cobalt molybdate mineral, the theoretical molecular formula CoMoO4·nH2O. The CMO particles demonstrated a distinctive rod-shaped morphology. Notably, under the optimal mass ratio (CMO/CNT=7/3), carbon nanotubes exhibited partial coverage of the CMO particle surface. Electrochemical hydrogen evolution experiments decisively illuminated the catalytic potency of the CMO-CNT composites, which effectively improved the HER efficiency. The CMO3CNT, distinguished by elevated electrochemically active surface area, yielded a lower HER overpotential of 171.5 mV (at 10 mA·cm−2) and Tafel slope of 69.9 mV dec−1. Importantly, the material demonstrated commendable catalytic stability across a 30-hour span of i-t tests and 3000 CV cycles. Density Functional Theory (DFT) analyses unveiled at the adept electron transfer capabilities in CNT and favorable catalytic ability exhibited in CMO contributed substantively to the composite's overall efficacy. The remarkable catalytic proficiency of CMO stemmed from the synergistic interplay between cobalt and molybdenum atoms. The amalgamation of both inherent advantages engendered the composite's pronounced electrocatalytic performance.

Keywords

• Hydrogen evolution reaction
• Hydrate CoMoO4
• Carbon nanotubes
• Electrocatalyst
• Density functional theory