The in situ FT-LR spectra were used to study the CO2 hydrogenation reaction over the SiO2-supported heterobinuclear metal complex catalysts, PtM (M = Cr, Mo, W). The bands, which correspond to the formate species absorbed on the catalysts, were observed. During the hydrogenation reactions, the adsorbed linear and bridging CO was not observed. The experimental results suggest that for the CO2 and CO hydrogenation reaction over the same catalysts, their catalytic active intermediate species and the reaction mechanisms should be different.