Hydroxyl-Decorated Pt as a Robust Water-Resistant Catalyst for Catalytic Benzene Oxidation

In catalytic oxidation reactions, the presence of environmental water poses challenges to the performance of Pt catalysts. This study aims to overcome this challenge by introducing hydroxyl groups onto the surface of Pt catalysts using the pyrolysis reduction method. Two silica supports were employed to investigate the impact of hydroxyl groups: SiO₂-OH with hydroxyl groups and SiO₂-C without hydroxyl groups. Structural characterization confirmed the presence of Pt-O, Pt-OH, and Pt⁰ species in the Pt/SiO₂-OH catalysts, while only Pt-O and Pt⁰ species were observed in the Pt/SiO₂-C catalysts. Catalytic performance tests demonstrated the remarkable capacity of the 0.5 wt % Pt/SiO₂-OH catalyst, achieving complete conversion of benzene at 160 °C under a high space velocity of 60,000 h^-1. Notably, the catalytic oxidation capacity of the Pt/SiO₂-OH catalyst remained largely unaffected even in the presence of 10 vol % water vapor. Moreover, the catalyst exhibited exceptional recyclability and stability, maintaining its performance over 16 repeated cycles and a continuous operation time of 70 h. Theoretical calculations revealed that the construction of Pt-OH sites on the catalyst surface was beneficial for modulating the d-band structure, which in turn enhanced the adsorption and activation of reactants. This finding highlights the efficacy of decorating the Pt surface with hydroxyl groups as an effective strategy for improving the water resistance, catalytic activity, and long-term stability of Pt catalysts.