Bridge the activity and durability of Ruthenium for hydrogen evolution reaction with the Ru-O-C link

Exploring efficient and robust electrocatalysts with low cost for hydrogen evolution reaction (HER) is critical for the practical application of electrochemical water splitting. Ruthenium (Ru)-based catalysts exhibit great po-tential in HER, whereas the extensive application is largely hampered by the insufficient performance and durability at current stage. In addition, understanding and revealing the activity enhancement mechanism of Ru-based catalysts is still very tempting while challenging. Herein, we use the oxygen-rich functional groups of graphene oxide (GO) to adsorb Ru species and in situ generate reduced graphene oxide supported Ru nano-particles (NPs) catalysts by annealing (Ru/rGO-700). Ru/rGO-700 exhibits low overpotential of 26 mV at 10 mA cm-2 in alkaline electrolytes, and simultaneously the strong interaction induced by the Ru-O bond between the support and the anchored Ru NPs endows the catalyst a desirable stability, thus the activity of the catalysts barely decays after 50,000 cycles of durability testing. Density functional theory (DFT) calculations demonstrate that the introduction of anionic oxygen leads to the electron-deficient characteristics of Ru NPs, which weakens the Ru-H affinity and accelerates/ or favors water dissociation and hydrogen desorption. In addition, the integrated crystal orbital Hamilton population (ICOHP) confirms that the introduction of electron holes weakens the an-tibonding interactions between Ru atoms, thus the stability of the catalysts is greatly improved.

Automated summary

In this study, reduced graphene oxide supported ruthenium nanoparticles catalysts were synthesized by annealing, and exhibited low overpotential and desirable stability in alkaline electrolytes. The introduction of oxygen-rich functional groups in graphene oxide improved the catalytic activity and stability of ruthenium catalysts by weakening the Ru-H affinity and strengthening the Ru-O bond.