Engineering Pt nanoclusters on CeO2 surface with abundant point defects by in situ confined-domain encapsulation strategy for the catalytic elimination of VOCs

Pt nanoclusters are a promising catalyst for VOC catalytic combustion, but they have been rarely studied so far. Herein, Pt nanoclusters (Pt NCs) and Pt nanoparticles (Pt NPs) were constructed by an in situ confined-domain encapsulation strategy, and then the reaction mechanism of Pt species on the catalytic combustion of VOCs was studied systematically. Interestingly, the addition process of Pt and Ce components greatly affected the dispersion and surface states of Pt species. The catalytic performance over PtNC@CeO2 (0.01 wt% Pt loadings) was proved to be of outstanding activity and stability, and the reason was related to the contribution of Pt nanoclusters and more lattice oxygen and Ce3+ species, whose formation was inextricably linked to the strong interfacial effect between Pt and CeO2. Notably, the in situ introduction approach of Pt species can effectively build up the point defects on the surface of CeO2 to promote the dispersion and anchoring of Pt species. In situ DRIFT spectroscopy verified that the role of lattice oxygen was significant in accelerating the catalytic oxidation of VOCs, and the oxidation process of toluene followed the reaction path: toluene → benzyl alcohol → benzaldehyde → benzoic acid → phenol → maleic anhydride → carbon dioxide and water. Meanwhile, the rate-determining step in the oxidation of toluene may be the further decomposition of alcohol or carboxylic acid intermediates.