Enhanced water gas shift reaction by CeO2 anchored Pt single atom catalyst

Pt/CeO2 were synthesized through the polyvinyl alcohol (PVA) reduction protection method, and the efficacies of the catalysts for water gas shift (WGS) reaction were evaluated. Pt was deposited on CeO2 in different forms of Pt single atoms (0.15Pt1/CeO2) and Pt nanoparticles (0.56Pt/CeO2), respectively. CO conversion (400 °C) and turnover frequency (TOF) (250 °C) of the Pt single atom catalyst 0.15Pt1/CeO2 were 89% and 0.85 s-1, respectively, significantly higher than that of the Pt nanoparticle catalyst 0.56Pt/CeO2 for the WGS reaction. The superior catalytic performance Pt single atom catalyst can be attributed to enhanced low-temperature reducibility and increased oxygen vacancies facilitated. In-situ diffuse reflectance infrared Fourier transform spectroscopy (in-DRIFTS) revealed that Pt single atoms promoted the creation of oxygen vacancies on CeO2, which dissociated H2O to H2 and adsorbed O, that subsequently interacted with the weakly adsorbed CO on these Pt sites to generate CO2. In contrast, the adsorption strength of CO nanoparticles Pt was much higher. CO reacted with the OH groups on the Pt nanoparticle catalyst surface to form formate species, which then decomposed to produce both CO2 and H2. This study presents a promising strategy for designing highly efficient catalysts tailored for WGS.