A DFT study on the catalytic hydrogenation of CO2 to formic acid over Ti-doped graphene nanoflake

Highlights: • The reduction of CO₂ by H₂ molecule is studied over a Ti-doped graphene nanoflake. • The formation of formate group is the rate-determining step. • The activation energy for the formation of formate is 0.85 eV. The aim of this study is to investigate the potential of Ti-doped graphene nanoflake (Ti-GNF) for the reduction of CO₂ to formic acid by H₂. To get a deeper insight into the mechanism of this reaction, the reliable DFT calculations are performed. It is found that the large positive charge on the Ti atom can greatly regulate the surface reactivity of GNF. The formation of the formate group is the rate determining step for the reduction of CO₂. The calculated activation energies demonstrate that Ti-GNF could be utilized as an efficient catalyst for the reduction of CO₂ to formic acid.