Surface Defect Engineering on Constructing High-Performance Noble Metal Active Sites: A Simple and Cost-Effective Path to High-Performance Oxidation Catalysts

Catalytic combustion is an efficient technology for the removal of volatile organic compounds (VOCs) as pollutants. Traditionally, noble metal catalysts have been used for the removal of VOCs. In this study, a Pd-CMO-AT60 catalyst with a high-performance active site (Pd–VO–Mn) was synthesized through an alkali treatment method. The catalyst demonstrated high catalytic activity and stability in toluene combustion compared to those of supported and doped Pd-based catalysts (Pd/CMO and Pd-CMO). At a temperature of 240 °C, the combustion rate of toluene on Pd-CMO-AT60 (8.24 × 10–8 mol·m–2·s–1) was found to be 6.87 times and 11.12 times higher than that on supported and doped Pd-based catalysts (Pd/CMO (1.20 × 10–8 mol·m–2·s–1) and Pd-CMO (7.41 × 10–9 mol·m–2·s–1)), respectively. The alkali treatment led to a reduction in the oxygen coordination of Pd on the Pd-CMO surface and introduced an active site, Pd–VO–Mn. Moreover, the copper coordination of lattice oxygen on the Pd-CMO-AT60 surface was also diminished, enhancing the mobility of the lattice oxygen. Oxygen was more easily adsorbed and dissociated on the Pd–VO–Mn site of Pd-CMO-AT60, and the dissociated oxygen on this site exhibited higher oxidation ability. Additionally, activated lattice oxygen lacking metal coordination on the Pd-CMO-AT60 surface displayed high oxidation performance. This study provides a simple and cost-effective approach for constructing high-performance noble metal active centers and serves as a reference for the development of Pd-based catalytic combustion catalysts.