Tailoring the electronic states of Pt by atomic layer deposition of Al2O3 for enhanced CO oxidation performance: Experimental and theoretical investigations

Abstract

Herein, atomic layer deposition (ALD)-Al2O3 films were applied as a medium to modulate the electronic states of the supported Pt. Based on the sacrificial template of ZIF-67, the ternary Co3O4/Pt/Al2O3 catalyst exhibited better performance in catalytic CO oxidation than the binary Co3O4/Pt catalyst. Both experimental and calculation results indicate the existence of charge transport between the Pt and the ALD-Al2O3 films, leading to electron-rich Pt, enhanced O2 affinity, and reduced activation energy. Interestingly, the oxidation resistance of Pt nanoparticles was visualized when annealing Co3O4/Pt/Al2O3 catalyst at high temperatures. Mechanism studies indicate the typical LH mechanism occurred in CO oxidation, showing that the co-adsorbed CO and O2 could be converted to carbonate-type *OCOO intermediates via low energy barriers. At low temperatures, CO2 was mainly produced by the lattice oxygen-mediated M-vK mechanism based on isotope labeling experiments. Our findings provide an alternative way to regulate the electronic states of noble metals by the ALD technique.