Heteroepitaxial Growth of Well‐Dispersed Co₃O₄ Nanocatalysts on Porous ZnO Nanoplates via Successive Hydrothermal Deposition

Abstract We report a unique successive hydrothermal deposition method for the heteroepitaxial growth of well‐dispersed crystalline Co₃O₄ nanoparticles on single‐crystalline porous ZnO nanoplates toward a Co₃O₄/ZnO nanocomposite catalyst. The specific heteroepitaxial crystal faces between Co₃O₄ and ZnO limit the size of Co₃O₄ particles to be approximately 5 nm and allow the exposure of more active sites. The intermediate of hydrozincite [Zn₅(CO₃)₂(OH)₆] plays a role as template in creating porous ZnO nanoplates and oriented Co₃O₄ grains via thermal decomposition process. The active exposure of the catalyst is probed by CO oxidation. The nanocomposite exhibits significantly enhanced catalytic efficiency towards CO oxidation at temperatures ranging from 30 to 115 °C, in comparison with a homogeneous Co₃O₄ sample and one‐step Co/ZnO products.