Pt-doped MnO x /AC catalyst for enhanced catalytic performance of formaldehyde at ambient temperature

Coating Manganese oxide (MnOx) onto solid substrates is one of the most effective approaches for addressing the inherent agglomeration tendency of powdered MnOx in practical applications. In this study, we deposited MnOx onto activated carbon (AC) and improved the catalytic performance for formaldehyde (HCHO) removal by introducing metal platinum (Pt). When evaluated as catalysts in the HCHO catalytic reaction at ambient temperature, the obtained 0.05 wt% Pt-MnOx/AC catalyst possessed remarkable catalytic and adsorption activity and stability. It could achieve 98% HCHO removal by degrading 1.01 ppm HCHO to 0.02 ppm (0.024 mg/m3) within 2 h at ambient temperature. Further structure-performance investigations revealed the crucial role of metal Pt, which not only improved the oxygen activation capacity but also increased the contents of adsorbed oxygen species and enriched oxygen vacancies; therefore, key intermediates, including performic acid, formate, and CO, can be easily converted. More importantly, the deactivated catalyst regained its full activity after 6 h of air exposure, which was attributed to the rapid regeneration of surface hydroxyl groups through atmospheric O2 and the oxidation of accumulated intermediates. This study reveals the HCHO catalytic mechanism over Pt-MnOx/AC and provides valuable insights into the design of high-activity, low-cost environmental catalysts.