Fabrication of cobalt (II, III) oxide @nitrogen doped carbon/honeycomb ceramics with porous structure for room-temperature formaldehyde oxidation

The content of surface cobalt active sites and oxygen vacancy (VO) is vital to the catalytic performance of Co3O4 catalysts. Herein, a robust Co3O4@N doped C supported on honeycomb ceramics (Co3O4@NC-HC) catalyst with porous structure was prepared by an impregnation-calcination method using ZIF-67 as the precursor. The N2 calcining atmosphere and relatively closed environment are beneficial for the formation of more pyridine N, Co3+ surface active sites, and VO, which favors formaldehyde (HCHO) or O2 adsorption and activation. The higher content of NC in Co3O4@NC-HC than in Co3O4@NC-HC-open and Co3O4@NC-HC-air can disperse Co-containing catalysts better and promote electron transfer. The Co3O4@NC-HC catalysts exhibited excellent activity and stability for HCHO oxidation at room temperature. The 1.0 Co3O4@NC-HC sample with theoretical 7.7 wt% showed the maximum efficiency (96.5 %) for HCHO removal. The related catalytic mechanisms over Co3O4@NC/HC for HCHO oxidation were posed.