Biomass-derived carbon supported cobalt-phospho-boride as a bifunctional electrocatalyst for enhanced alkaline water splitting†

Abstract

Developing efficient and low-cost bifunctional electrocatalysts for overall water splitting in order to reduce the future energy crisis is crucial and challenging. Herein, a facile two-step fabrication via pyrolysis and chemical reduction was used for the synthesis of biomass-derived carbon-based electrocatalyst (MT) from mulberry bark and its subsequent modification with cobalt phospho-boride (MT/CoPB) for efficient bifunctional electrocatalysis in alkaline media. The effect of B/P ratios and carbon-to-metal ratios on electrocatalytic performance of HER was investigated. Notably, the optimized MT/CoPB catalyst (B/P = 5, C : M = 2 : 1) exhibited a lower overpotential of −86 mV for HER and 310 mV for OER to reach the current density of 10 mA cm⁻². The robust electrocatalytic performance of MT/CoPB towards the HER and OER was attributed to the combined effect of carbon and CoPB. Notably, it achieved a low cell voltage of 1.59 V to reach a current density of 10 mA cm⁻², also maintaining reliable long-term stability. Characterization studies revealed that the enhanced performance was due to the amorphous structure of the catalyst, high electrochemical surface area, and efficient charge transfer. This work demonstrates the potential of biomass-derived carbon-based materials in the development of cost-effective and durable electrocatalysts for water splitting and green hydrogen production.