Ru/RuO₂ Nanoparticle Composites with N-Doped Reduced Graphene Oxide as Electrocatalysts for Hydrogen and Oxygen Evolution

Engineering nanocomposites with interfaces was already found to be an efficient method for designing water-splitting catalysts. In this study, a rationally designed 3D Ru/RuO2@N-rGO hierarchical porous heterocatalyst containing abundant interfaces was obtained via a hydrothermal-calcining strategy for the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). In the synthesis process, polypyrrole helped the self-assembled GO to form a hybrid aerogel network, in situ reducing the Ru salt as reductant and doping graphene as N precursor. CO2, which was in situ produced via the reaction between Na2SO4 and C, could partially or totally oxidize metal Ru to regulate the composition of Ru/RuO2 nanoparticles. Benefiting from the large surface area and a high number of bifunctional active sites coupled interfaces, the as-obtained Ru/RuO2@N-rGO heterostructure catalyst revealed high HER/OER activities in 1.0 M KOH and 0.5 M H2SO4 solutions, respectively. The present work could provide a way to engineer Ru/RuO2 nanoparticles in 3D electrocatalysts to boost HER/OER performances.