Convenient Synthesis of a Ru Catalyst Containing Single Atoms and Nanoparticles on Nitrogen-Doped Carbon with Superior Hydrogen Evolution Reaction Activity in a Wide pH Range.

Ruthenium, which is relatively cheap in precious metals, has become a popular alternative for a hydrogen evolution reaction (HER) catalyst because of its corrosion resistance and appropriate metal-H bond strength. Convenient synthesis and active site regulation are conducive to stimulating the excellent catalytic performance of Ru as much as possible. Herein, using the mature mesoporous nitrogen-doped carbon material as the support, the catalytic materials containing both single atom Ru and Ru nanoparticles were synthesized by impregnation using the solid-phase reduction method. The effect of reduction temperature on the dispersion state and electronic structure of Ru species has been fully studied using electronic and spectroscopic characterizations. The sample reduced at 300 °C has excellent HER activity with overpotentials of 10.8 and 53.8 mV to deliver 10 mA/cm 2 in alkaline and acidic media, respectively, which is among the best activities in the reported results. Electrochemical impedance analysis shows that the reduction temperature has a great influence on the number of active sites and charge transfer impedance of the catalyst.