Iron-doped ZnO as a support for Pt-based catalysts to improve activity and stability: enhancement of metal-support interaction by the doping effect

In heterogeneous catalysis, the role of the interface between a metal and a metal oxide in deciding catalytic performance has remained a long-standing question. Out of many molecular-scale factors that affect the properties of metal-oxide interfaces, doping or impurities in the oxides can result in excess charge carriers or oxygen vacancies on the oxides, which lead to a change in catalytic activity. For a model system with a tunable dopant, we employed Pt nanoparticles with Fe doping. We synthesized a series of Fe-doped ZnO with different Fe loadings (i.e., 0, 1, and 4%) using the co-precipitation method, and then deposited Pt nanoparticles onto these supports. The Pt-based catalysts were employed to investigate the effect of the dopant to promote the catalytic performance for the CO oxidation reaction. The 4% Fe loading sample showed the highest catalytic activity among the catalysts, with a turnover frequency of 5.37 s^-1 at 126 °C. The dopant was found to enhance the interaction between the Pt nanoparticles and the catalyst support, including the prevention of metal sintering, which resulted in an improvement of catalytic activity.