In-situ preparation of molybdenum trioxide-silver composites for the improved photothermal catalytic performance of cyclohexane oxidation

The selective catalytic oxidation of cyclohexane has important theoretical and practical application value. However, high conversion rate and high selectivity are difficult to achieve simultaneously by conventional catalytic system. In this work, blue molybdenum trioxide (MoO3) nanorods with oxygen vacancies were prepared by hydrothermal method using hydrated molybdic acid as a precursor under the reduction of formic acid, and in-situ produced MoO3-silver (MoO3-Ag) composites were further used in the photothermal catalytic oxidation of cyclohexane with high conversion and high selectivity using dry air as oxidant. The results showed that the best conversion rate of cyclohexanone and cyclohexanol (KA oil) could reach 8.6% with the selectivity of 99.0%. The excellent catalytic performance of MoO3-Ag composites can be attributed to the significantly increased visible and near-infrared light absorption caused by the plasma resonance effect of Ag nanoparticles and oxygen vacancies, and the prevented charge recombination by MoO3-Ag Schottky heterojunction. This work provides new reference solutions for the design and preparation of high-performance photothermal catalysts for the selective oxidation of hydrocarbons.