Mechanistic Study of Active O* Generation in HCHO Oxidation on Pt/TiO₂ (110) Surface

Pt/TiO₂ catalysts show superior catalytic performance for HCHO removal. Unraveling the detailed mechanism of HCHO oxidation on Pt/TiO₂ is of great importance in guiding robust catalyst design. Herein, HCHO oxidation on Pt/TiO₂ (110) surface is studied by using density functional theory calculations. The results show that HCHO adsorbed at the Pt/TiO₂ interface and subsequent successive dehydrogenation formed CO* species. The Pt site acts as the active center for O₂ activation, and there is a positive linear relationship between the electrons accumulated on Pt site with O₂ adsorption energy. To elucidate how the active O* species is produced, the direct OO bond cleavage and hydrogen-assisted OOH bond cleavage are examined. With hydrogen assistance, the activation barrier of OOH bond cleavage is lowered to 0.33 eV, and the reaction is strongly exothermic (-1.48 eV), indicating that the hydrogen-assisted OOH cleavage path is both kinetically and thermodynamically more favorable. The present work provides mechanistic insight into HCHO oxidation on the Pt/TiO₂ (110) surface and useful guidance in catalyst design with high efficiency.