Size-controllable Rh2P nanoparticles on reduced graphene oxide toward highly hydrogen production

Abundant of defective regions and oxygen-containing groups on graphene oxide (GO) could promote the nucleation and growth of metallic nanoparticles . In this work, the composite catalyst is synthesized by pyrolysis of the mixture powder of GO and rhodium organometallic reactant at 900 °C, Ar atmosphere and low pressure, in which dispersive Rh 2 P nanoparticles are uniformly attached on reduced graphene oxide (Rh 2 P/RGO). The sizes of Rh 2 P nanoparticles are controllable by adjusting the mass proportion of reactants. For the optimized size of Rh 2 P nanoparticles at 6.0 nm, only 11.7 and 10.3 mV of the overpotentials are required at the current density of 10 mA cm −2 in 0.5 M H 2 SO 4 and 1 M KOH electrolytes, respectively, exhibiting superior HER activity over the commercial Pt/C. Theoretical calculations indicate that the hydrogen adsorption free energy of Rh 2 P/RGO composites is close to zero, and Bede charge analysis confirms the accelerated electron transport between the RGO and Rh 2 P. Therefore, the introduction of RGO substrate could not only promote a uniform distribution and tunable size of Rh 2 P NPs, but also be advantageous to the electron transport from RGO to Rh 2 P NPs, and a favorable H 2 evolution during the HER process. This work provides a facile strategy to control the size of metal phosphide nanoparticles on RGO for the design of advanced HER electrocatalysts .