Spent Zinc–Carbon Battery-Derived Carbon Nanoparticles Coupled with Transition Metal Dichalcogenides for Enhanced pH-Universal Hydrogen Evolution Reaction

Abstract

Utilizing highly effective waste-into-value electrocatalysts for the hydrogen evolution reaction (HER) opens a sustainable route to economically beneficial and environmentally friendly hydrogen production. A simple strategy for reusing spent batteries involves enhancing HER performance by preparing electrocatalysts of the carbon anode in spent zinc–carbon batteries and transition metal dichalcogenide (TMDs) materials. In this study, carbon nanoparticles (C_NPs) are incorporated into the basal planes of MoS₂ and WS₂ using a simple ultrasonication method. C_NPs@TMDs (C_NPs@WS₂ and C_NPs@MoS₂) with fewer-layer structures and enhanced exposed active sites show promising catalytic activity for pH-universal HER. In acid, C_NPs@WS₂ and C_NPs@MoS₂ exhibit overpotentials of 0.34 and 0.42 V at 10 mA cm^–2, with Tafel slopes of 0.139 V dec^–1 and 0.145 V dec^–1, respectively. The enhanced HER performance of C_NPs@TMDs originates from their improved electrical conductivity and higher electrochemically active surface area. Alongside experimental results, density function theory (DFT) calculations reveal that incorporating carbon atoms on the TMD surface can efficiently tune the electronic properties of MoS₂ and WS₂ monolayers from semiconductor to semimetal and considerably reduces the hydrogen adsorption Gibbs free energies. These results indicate that highly effective HER catalysts with enhanced catalytic activity in universal pH media are fabricated via an economical and facile method, holding promise for practical applications and paving the way for battery recycling.