First principles investigations of the carbon dioxide reduction to ethylene over the M₁₀@TiO₂ catalysts

Cu metal clusters loading on the surface of TiO₂ served as co-catalyst can catalyze the reduction of CO₂ to C2 products. However, the details mechanism of this reaction is still not clear. Moreover, finding other metal clusters to replace Cu is an attractive subject. In this work, the C-C bond forming mechanism by two CO* on several metal clusters (Cu, Ga, Co, Fe, Ni, Pt, Pd, Mo, and Zr) loading on TiO₂ (101) surface (M₁₀@TiO₂) were investigated by climbing image nudged elastic band (cNEB) within density functional theory (DFT). We found the energy barrier of C-C bond forming on Cu₁₀@TiO₂ and Ga₁₀@TiO₂ is low around 0.7 eV which indicates that they are efficiency co-catalyst in CO₂ reduction to C2 products. For other metal clusters, the energy barrier is large around 1.5 eV, and they are exclude comparing to Cu and Ga clusters. The reaction path to C₂H₄ has also been calculated on Cu₁₀@TiO₂ and Ga₁₀@TiO₂. The step energy on Ga₁₀@TiO₂ is all smaller than the energy barrier of C-C bond forming which makes Ga₁₀@TiO₂ may as be good as Cu₁₀@TiO_2. This work provides useful insights into the CO₂ reduction to C2 products on metal clusters loading on TiO₂ catalyst.