Atomic rhodium catalysts for hydrogen evolution and oxygen reduction reactions

High specific activity of single-atom catalysts shows great application potentials in water splitting and fuel cell systems. Herein, we report a facile pyrolysis method to fabricate an atomically dispersed rhodium catalyst ([email protected]). The [email protected] exhibits outstanding electrochemical activities and kinetics for oxygen reduction reaction in alkaline medium, which can compare to Pt/C catalysts, along with excellent durability and good tolerance to methanol and carbon monoxide. The half-wave potential on [email protected] in 0.1 M KOH and 0.1 M HClO4 is 0.848 and 0.74 V vs RHE, respectively. Additionally, the [email protected] displays superior performance for hydrogen evolution reaction, offering a low overpotential of only 29, 33, and 45 mV at 10 mA cm−2 in 0.5 M H2SO4, 1.0 M KOH, and 0.1 M KOH, respectively. Theoretical calculations reveal that the efficient active sites for HER and ORR might be RhN3 and RhN4 moiety embedded into the N-doped graphene, respectively.