Enhanced formic acid production for CO₂ photocatalytic reduction over Pd/H-TiO₂ catalyst

The photocatalytic reduction of CO₂ into formic acid is a feasible approach to alleviate the effects of global climate change and achieve chemical energy storage. It is important to design highly active photocatalysts to improve the selectivity and yield of formic acid. In this study, TiO₂-based catalysts were prepared and loaded with Pd nanoparticles via an impregnation process. The Pd/H-TiO₂ catalyst demonstrated superior CO₂ reduction activity and a high formic acid production rate of 14.14 mmol_cat·g⁻¹·h⁻¹. The excellent catalytic performance observed in the presence of a Pd/H-TiO₂ catalyst is ascribed to the synergy between O_v and Pd. The presence of O_v led to increase in CO₂ adsorption while Pd loading enhanced the photogenerated electron-hole pair separation. Electron transfer from H-TiO₂ to Pd also contributed to CO₂ activation.