A DFT and microkinetic study of HCHO catalytic oxidation mechanism over Pd/Co3O4 catalysts: The effect of metal-oxide interface

•The interface interaction leads to the electron migration from Pd to Co3O4, which enhanced the adsorption of HCHO and O2.•Both Pd/Co3O4 interface and Pd (111) surface exhibit greater ability to dissociate C–H bond than Co3O4 surface.•Pd/Co3O4 interface has lower CO activation energy than Pd (111) surface, which contributes to CO oxidation.•The production rate of CO2 and H2O at Pd/Co3O4 interface is fifteen orders of magnitude higher than that on Pd (111) surface