Uniformly dispersed ruthenium nanoparticles on porous carbon from coffee waste outperform platinum for hydrogen evolution reaction in alkaline media

Abstract Biowaste-derived carbon materials are a sustainable, environmentally friendly, and cost-effective way to create valuable materials. Activated carbon can be a supporting material for electrocatalysts because of its large specific surface area and porosity. However, activated carbon has low catalytic activity and needs to be functionalized with heteroatoms, metals, and combinations to improve conductivity and catalytic activity. Ruthenium (Ru) catalysts have great potential to replace bench market catalysts in hydrogen evolution reaction (HER) applications due to their similar hydrogen bond strength and relatively lower price. This study reports on the synthesis and characterizations of carbon-supported Ru catalysts with large surface areas (~1,171 m 2 g -1 ) derived from coffee waste. The uniformly dispersed Ru catalyst on the porous carbon has excellent electrocatalytic activity and outperformed the commercial catalyst platinum on carbon (Pt/C) toward the HER. As-synthesized catalyst needed a 27 mV to reach a current density of 10 mA cm −2 , 58.4 mV dec -1 Tafel slope, and excellent long-term stability. Considering these results, the Ru nanoparticles on coffee waste-derived porous carbon can be utilized as excellent material that can replace platinum-based catalysts for the HER and contribute to the development of eco-friendly and low-cost electrocatalyst materials.