Enhanced activity and stability of Ru-TiO₂ rutile for liquid phase ketonization

Stabilization of oxygen vacancies on metal oxides (e.g. TiO₂) in liquid phase is an important challenge for the utilization of these materials in artificial photosynthesis, environmental remediation and biomass conversion. To create materials with low-energy barriers for vacancies formation and high stability in aqueous environments, we have developed partially hydrophobic (contact angle ≥90°) TiO₂ rutile decorated with Ru nanoparticles. Negligible catalytic activity was observed when hydrophilic (contact angle 51°) 5 wt.% Ru/TiO₂ anatase was utilized in hot liquid water, while amphiphilic 5 wt.% Ru/TiO₂ rutile (contact angle ∼90°) retained its catalytic activity. Fine-control of crystalline structure (lattice matching) of TiO₂ and Ru allowed us to accelerate the rate of reaction, while the high surface hydrophobicity of the support enabled the stabilization of Ti³⁺ cations in aqueous and organic environments.