Facet engineering of Nano-Co3O4 for catalytic and gas sensor performance: A mechanism insight

Abstract The deep comprehension of catalytic and gas sensing property and structure-activity relationships for Co3O4 remains challenging. Comparing and analyzing the property of Co3O4 with different exposed facets could recognize and understand the corresponding mechanism on an atomic or ionic level. Here, Co3O4 nanocube and nanoplate with their dominant exposed facets of {100} and {112} were prepared and the peroxidase mimics and gas sensor tests at room temperature have been implemented. Both the peroxidase-like activity and gas sensing properties indicate that the activity performance was related to the exposed facets closely. The peroxidase-like activity followed the order of exposure facets: {112} > {100}, and NO2 gas sensing performance shows the order: {100} > {112}. To clarify the intrinsic mechanism of structure-activity relationship, the density functional theory (DFT) was developed. The essence of crystal shape and exposure facet effect is understood through the different surface atoms arrangements and adsorption toward target substrates, thus exhibiting different electron affinity abilities, which induce their different catalytic activities.