The catalytic oxidation of formaldehyde over palygorskite-supported copper and manganese oxides: Catalytic deactivation and regeneration

The emission of volatile organic compounds (VOCs) from industrial and commercial processes is detrimental to human health and the environment. Though numerous catalysts have been reported to eliminate the pollution of VOCs, their deactivation and regeneration are still largely unknown. In this study, the prepared palygorskite-supported Cu-Mn oxides displays slight decrease of catalytic activity in the initial stage of formaldehyde oxidation. After the thermal treatment of spent catalyst at 400 °C, the catalytic activity is partially recovered. A deactivation and regeneration mechanism is proposed, based on the stability test and the comprehensive characterizations of fresh and spent catalysts. The accumulation of formate species and the depletion of oxygen on the surface of Cu-Mn oxides are responsible for the decline of activity. Thermal treatment of deactivated catalyst at 400 °C recovers the catalytic activity because it gasifies the carbonaceous intermediates and replenishes surface oxygen. The obtained results will be of great significance for the application of transition metal oxide-based catalysts in the abatement of VOCs.