Dual-template synthesis of defect-rich mesoporous Co3O4 for low temperature CO oxidation

Abstract

CO oxidation is a benchmark in heterogeneous catalysis for evaluation of redox catalysts due to its practical relevance in many applications and the fundamental problems associated with its very high activity at low temperatures. Among which, Co3O4 is one of the most active non-precious metal catalysts. Exposed crystal planes and cobalt sites are considered to be important for its high catalytic activity. Herein, we demonstrate an enhanced CO oxidation activity by a defect-rich mesoporous Co3O4 that prepared by a designed dual-template method. Two different kinds of silicas are used as hard-templates at the same time, resulting in a defect-rich mesoporous Co3O4 with a surface area as high as 169 m2/g. This catalyst exhibited a very high catalytic activity for low temperature CO oxidation with a light-off temperature at −73 oC under the space velocity of 80,000 mL h-1 gcat-1. Further studies reveal that the high surface area promotes the lattice oxygen mobility, surface rich of Co2+ species and active oxygen species are crucial for the high catalytic activity. Moreover, the dual-template approach paves a way towards the design and construction of high-surface-area mesoporous metal oxides for various applications.