Nanoclay-modulated oxygen vacancies of metal oxide

The formation of oxygen vacancies is one of the most critical factors that can improve the electronic and catalytic properties of metal oxides, in which an important challenge is to lower the formation energy of oxygen vacancies at the interface structure. Here we show that clay surfaces rich with hydroxyl groups can induce the formation of oxygen vacancies in metal oxide catalysts. Based on density functional theory calculations, kaolinite is shown to hinder the surface dehydration process of Co3O4 nanoparticles, and enhances the charge transfer process at the interface by the highly diffusible protons. Experimental results confirm that vacancy-rich Co3O4 is easily produced by a reduction method and kaolinite enhances the formation of oxygen vacancies and divalent cobalt on the nanoparticle surface. As expected, the defective Co3O4/kaolinite exhibits enhanced catalytic and electrocatalytic performances. This finding provides an improved way to design efficient clay-based catalysts.