Lithium promotes Ag-CoOx composite for formaldehyde oxidation at ambient temperature: Chemically adsorbed oxidative oxygen formed by the interaction between AgCoO2 and catalyst parent.

Catalytic oxidation at ambient temperature dominates priority in airborne formaldehyde elimination. Herein, the effects of Li⁺, Na⁺ and K⁺ on the catalytic activity of Ag-CoO x composite were comparatively studied. Systematic methods were applied to investigate the factors influencing catalytic activity. Compared with the cases of Na⁺ and K⁺, for which the combination with Ag species respectively deteriorated and limitedly increased formaldehyde removal, the incorporation of Li⁺ greatly boosted formaldehyde degradation. Characterization results certify that the largest amount of chemically adsorbed active oxygen was crucial to the excellent performance of Li-Ag-CoO x , and the advanced oxidizing property can be rationalized by the strong interaction between the exclusively formed AgCoO 2 and the catalyst parent. This is the first time to clarify the roles of varied alkaline metals in the complete oxidation of formaldehyde catalyzed by Ag-CoO x materials. Effects of process variables were additionally investigated to uncover the catalyst suitability for in-field application. [Display omitted] • Effect of alkaline metals on HCHO oxidation by Ag-CoO x is studied for first time. • Combination of Ag with Li⁺ greatly elevates the oxidation ability. • Active component AgCoO 2 is formed vIa ion exchange with Li⁺. • Close contact of AgCoO 2 with catalyst parent creates sufficient chemisorbed oxygen. • Catalytic transformation processes of HCHO are finally raised. [ABSTRACT FROM AUTHOR]