High-dispersed ruthenium sites on copper phosphide/graphene for electrocatalytic hydrogen evolution in acidic and alkaline conditions

Here, the novel Ru single-atomic sites (SAs) with Cu3P nanoparticles supported on chemically converted graphene (Cu@Cu3P-Ru/CCG) is synthesized as HER catalysts. The TEM result reveals that the average diameter of Cu@Cu3P-Ru/CCG-500 nanoparticles (NPs) is 2 nm. AC-HAADF-STEM and Ru K-edge XAFS results uncover that the bonding environment of Ru is atomically dispersed on Cu3P and chemically converted graphene. Cu@Cu3P-Ru/CCG-500 exhibits a small overpotential of 32.97 mV to reach a current density of 10 mA cm−2 (j10) in 1 M KOH (102.52 mV in 0.5 M H2SO4). Meanwhile, its Tafel slope is 66.40 mV dec−1 in 1 M KOH (63.00 mV dec−1 in 0.5 M H2SO4). Density functional theory (DFT) calculations disclose that the Ru SAs on Cu3P facilitate H2O dissociation and Ru SAs on CCG promote H* to form hydrogen.