Fig. 3: DRIFTS studies of CO bonds on Pt nanoclusters under CO and WGS conditions.

The experiments were performed by decreasing the temperature from high to low. a The temperature-dependent CO – DRIFTS spectra of Pt/CeO₂ catalyst collected in the ramp-down process. Bands in high frequency (HF) region (2072–2054 cm⁻¹) are assigned to linearly adsorbed CO on terrace or step Pt sites^18,22,53,54. In low frequency (LF) region, the band centered at ~2016 cm⁻¹ is assigned to CO linearly adsorbed on perimeter Pt sites while the band centered at ~1956 cm⁻¹ is assigned to a bridged CO adsorption at the metal support interface^{18,19,20,21,22,23,24}. b–f At 300 °C, 240 °C, 180 °C, 120 °C, and 26 °C, the changes of CO bands on the Pt surface sites upon the change of condition from CO to WGS. The positions of HF peaks were labeled in Supplementary Fig. 6.