Engineering Ru nanoparticles on cotton stalk waste-derived carbon for efficient hydrogen evolution reaction

Abstract

The development of efficient and long-term stable Pt-substituting catalysts for the hydrogen evolution reaction (HER) is essential for the practical application of water splitting. Herein, a Ru/C catalyst was synthesized via high-temperature pyrolysis of a mixture of cotton stalk waste and RuCl₃ at 800 °C for 2 h. The prepared Ru/C catalyst exhibited an aggregated structure with Ru nanoparticles dispersed on cotton stalk waste-derived carbon and possessed a specific surface area of 78.84 m² g⁻¹ and porous structure. For the HER, the Ru/C catalyst demonstrated remarkable electrocatalytic performance, characterized by a low overpotential of 63 mV at 10 mA cm⁻², small Tafel slope of 59.6 mV dec⁻¹, and notable long-term stability over 30 h at 10 mA cm⁻² and 1000 cyclic voltammetry cycles. This excellent performance arises from carbon layer-mediated charge transfer, impedance reduction, and Ru protection, alongside a nanostructure-enabled active site increase and transport optimization for fast kinetics. This study offers a simple and efficient approach for producing cost-effective, highly efficient HER catalysts while promoting high-value utilization of agricultural waste.