Highly active and water-resistant Lanthanum-doped platinum-cobalt oxide catalysts for CO oxidation

The presence of interfacial sites between Pt-group metals and transition metal oxides can effectively improve the catalytic activity of Pt-group catalysts, but under moisture-rich conditions they suffer from severe deactivation due to water poisoning of the active sites. Here, we propose for the first time a Lanthanum (La)-doping strategy to improve the water-resistance of the Pt-based catalysts. We synthesized a Pt-CoO/Al2O3 catalyst that is active for CO oxidation under dry conditions but deactivates rapidly under moisture. This rapid deactivation is overcome by La-doping, which delivers boosted activity (100 % CO conversion at 15 °C) and long-term on-stream stability. In situ X-ray absorption fine-structure and in situ diffuse reflectance infrared Fourier transform spectra revealed that the doped La, in the form of La2O3, plays dual roles of suppressing the carbonate formation on the active sites and modifying the electronic structure of Pt. The synergetic effects between La2O3 and the active Pt−O−Co interfacial sites in La-doped Pt-CoO/Al2O3 lead to the outstanding activity under the moisture-rich condition.