Ru nanoassembly catalysts for hydrogen evolution and oxidation reactions in electrolytes at various pH values

Here, in an effort to prepare Ru-based metal organic frameworks, we developed a one-step solvothermal synthesis for Ru nanoassembly catalysts, which consist of ˜4 nm Ru nanoparticles well dispersed on amorphous carbon (Ru/C). The Ru/C catalyst obtained from a mixed solvent of H2O and CH3CH2OH (Ru/C-H2O/CH3CH2OH), featured a chain-like porous structure, provides Pt-like catalytic properties with low overpotentials at −10 mA cm−2 for the hydrogen evolution reaction (HER) within a wide range of pH values, i.e., 35 mV in 0.5 M H2SO4, 53 mV in 1.0 M KOH, and 93 mV in 3.5 wt% NaCl. Ru/C is also an efficient hydrogen oxidation reaction (HOR) catalyst at all pH values. In the alkaline media, Ru/C-H2O/CH3CH2OH achieves a mass activity of 41.1 mA mg-1 at an overpotential of 50 mV and a high exchange current density (0.65 mA cm−2). The work provides a facile strategy to synthesize highly active Ru/C catalysts for bifunctional HER and HOR electrocatalysis.