Hierarchical 0D/2D Co3O4 hybrids rich in oxygen vacancies as catalysts towards styrene epoxidation reaction

Abstract

Great efforts have been devoted to the developing of simple, efficient and stable heterogeneous catalysts for the styrene epoxidation reaction (SER). Metal oxides can be of industrial importance by offering an economic and green route for selectively converting styrene into styrene oxide (SO). Herein, by treating the pristine porous 2D Co3O4 sheets with NaBH4 solution, a novel hierarchical structure, i.e., 0D Co3O4 nanoparticles decorated on 2D porous Co3O4 sheets, was obtained. This simple solution reduction strategy not only realizes the morphology evolution, but also induces the modification of the valence states of metal ions and the simultaneous generation of surface oxygen vacancies. The hierarchical 0D/2D Co3O4 hybrids rich in oxygen vacancies (OV-Co3O4) exhibit a much better SER performance than the Co3O4 sheets (P-Co3O4), with the yield of SO more than doubled. The excellent catalytic performance of the OV-Co3O4 can be ascribed to the synergistic effects regarding the hierarchical porous structure, the modification of surface chemical composition and the creation of surface oxygen vacancies.