Exploring active and low-cost transition metal oxides (TMOs) based catalysts for volatile organic compounds (VOCs) abatement is vital for air pollution control technologies. Since 18 oxygen atoms are required for the complete mineralization of a toluene molecule, the participation of a large amount of active oxygen is a key requirement for the catalytic oxidation of toluene. Here, toluene degradation was improved by weakening the Co–O bond strength on the surface of cobalt oxide, so as to increase the amount of active oxygen species, while maintaining the high stability of the catalyst for toluene combustion. The bond strength of Co–O and the amount of surface active O2 was regulated by tuning the pyrolysis temperature. The catalyst’s redox ability and surface oxygen species activity are improved due to the weakening of the Co–O bond strength. It has been demonstrated that active oxygen plays a crucial role in boosting toluene combustion by engineering Co–O strength in cobalt oxide catalysts. This work provides a new understanding of the exploration and development of high-performance TMO catalysts for VOCs abatement.

It is challenging for selective catalytic reduction (SCR) of NO x by NH 3 due to the coexistence of heavy metal and SO 2 in the flue gas. A thorough probe into deactivation mechanisms is imperative but still lacking. This study unravels unexpected offset effects of Cd and SO 2 deactivation over CeO 2 -WO 3 /TiO 2 catalysts, potential candidates for commercial SCR catalysts. Cd-and SO 2 -copoisoned catalysts demonstrated higher activity for NO x reduction than a Cd-poisoned catalyst but lower than that for an SO 2 -poisoned catalyst. In comparison to SO 2 , Cd had more severe effects on acidic and redox properties, distinctly decreasing the SCR activity. After sulfation of Cd-poisoned catalysts, SO 4 2− preferentially bonded with the surface CdO and released CeO 2 active sites poisoned by CdO, thus reserving the highly active CeO 2 -WO 3 sites and maintaining a high activity. The sulfation of Cd-poisoned catalysts also provided more strong acidic sites, and the synergistic effects between the formed cerium sulfate and CeO 2 contributed to the high-temperature SCR performance. This work sheds light on the deactivation mechanism of heavy metals and SO 2 over CeO 2 -WO 3 /TiO 2 catalysts and provides an innovative pathway for inventing high-performance SCR catalysts, which have great resistance to heavy metals and SO 2 simultaneously. This will be favorable to academic and practical applications in the future.

In situ formed LiF grains are confined and evenly distributed throughout a covalent organic framework (COF) film, which exhibits cooperative effectiveness to greatly stabilize the lithium metal.