Ruthenium nanoparticles supported on S-doped graphene as an efficient HER electrocatalyst

Abstract

The development of highly active HER catalysts is of great significance for the preparation of high-purity green hydrogen. Although Pt has the best catalytic activity for the hydrogen evolution reaction, its high price and scarcity greatly reduce its large-scale industrial application prospects. Herein, we applied a simple method to synthesize an efficient HER catalyst (Ru@SGO), and its performance is comparable to that of Pt/C. Graphene is used as the substrate to improve the conductivity of the material, and sulfur doping is used to improve the catalytic performance. We treated graphene oxide with Lawesson reagent to obtain a sulfur-enriched graphene, then ruthenium nanoparticles were coated to obtain the efficient HER catalyst Ru@SGO. The results show that the high catalytic activity of Ru@SGO comes from ruthenium nanoparticles, and sulfur doping also plays an important role. For Ru@SGO, in 0.5 M H₂SO₄, the overpotential is 69 mV at 10 mA cm⁻² and the Tafel slope is only 52 mV dec⁻¹, which is higher than that of Ru@GO (96 mV, 79 mV dec⁻¹). In 1 M KOH, the overpotential is only 33 mV at 10 mA cm⁻² and the Tafel slope is only 56 mV dec⁻¹, which is also higher than that of Ru@GO (73 mV, 128 mV dec⁻¹). SCN⁻ poisoning experiments show that ruthenium nanoparticles play a decisive role in the catalytic performance of the HER. In addition, sulfur doping changes the charge distribution of graphene and effectively improves the intrinsic activity of the catalyst.