Radiation synthesis of size-controllable ruthenium-based electrocatalysts for hydrogen evolution reaction

Ruthenium decorated reduced graphene oxide (Ru/rGO) catalysts were synthesized through gamma-ray radiation induced reduction in aqueous media without additive reducing agent. The investigation of dose rate and RuCl3 concentration on the size of Ru nanoparticles (NPs) showed that both higher dose rate and lower precursor concentration contributed to smaller size. Then the formation mechanism of Ru NPs with different size was discussed in detail based on the principle of radiation-induced reduction reaction and nanocrystals growth. Finally, the Ru/rGO catalysts were applied in hydrogen evolution reaction (HER) under alkaline media. It is found that the size and content of Ru NPs played a critical role in the activity of HER and the Ru/rGO catalysts prepared at the dose rate of 365 Gy/min and RuCl3 concentration of 2 mM with a Ru diameter of ca. 2.1 nm showed excellent HER performance than commercial Pt/C especially at higher current density. It is expected that the result gained from this study may provide a scientific base for the future synthesis of novel Ru-based electrocatalysts.