Ru Species Supported on MOF-Derived N-Doped TiO2/C Hybrids as Efficient Electrocatalytic/Photocatalytic Hydrogen Evolution Reaction Catalysts

The development of efficient catalysts is of great importance for hydrogen evolution reaction (HER) of water splitting via electrocatalytic/photocatalytic processes to remediate the current severe environmental and energy problems. By aid of the stabilization effects of uncoordinated groups and inherent pore-confinement of amine-functionalized metal-organic frameworks (NH2-MIL-125), two forms of Ru species including nanoparticles (NPs) and/or single atoms (SAs) can be firmly embedded in NH2-MIL-125 derived N-doped TiO2/C support (N-TC), and thus obtain two kinds of samples named Ru-NPs/SAs@N-TC and Ru-SAs@N-TC, respectively. In the synthetic process, the initial feeding amount of Ru(3+)ions not only strongly determines the final size and dispersion states of Ru species but also the morphology and defective structures of N-TC support. Impressively, Ru-NPs/SAs@N-TC exhibit superior catalytic activities to Ru-SAs@N-TC for either electrocatalytic or photocatalytic HER. This should be attributed to its larger specific surface area and benefiting from synergistic coupling of Ru NPs and Ru SAs. It is envisioned that the present work can provide a new avenue for development of high-efficiency and multifunctional hybrid catalysts in sustainable energy conversion.