Constructing double-tuned Ru nanoparticles and Co single atoms on MXene/TiO₂ heterojunctions as for efficient oxygen evolution reaction electrocatalyst

Water electrolysis to produce hydrogen has broad prospects due to its pollution-free feature, yet its electrolysis efficiency is limited by the slow kinetics of the anodic oxygen evolution reaction (OER). In this study, we develop a synergistic catalyst which integrates MXene/TiO₂-supported Ru nanoparticles and oxygen-coordinated Co single atoms (RuCo-MXene/TiO₂) for efficient OER. This double-tuned structure enables both high-density active sites and precise microenvironment control. Moreover, the interaction between metals during annealing process provides the generation of metallic-bonded Ru-Co pairs between Ru nanoparticles and Co single atoms, facilitating Ru nanoparticles-to-support charge transfer, resulting in optimized electronic properties of the catalyst. As expected, the as-synthesized RuCo-MXene/TiO₂ catalyst at 10 mA·cm⁻² current density exhibits 208 mV low overportential and a long-term stability of up to 500 h, which is superior to Ru-MXene/TiO₂ and Co-MXene/TiO₂. This work provides a promising strategy for designing efficient and stable electrocatalysts for renewable energy applications.