Z-scheme WO3-Co3O4 heterojunction for the boosted photo-thermo catalytic oxidation of cyclohexane

Abstract

The selective catalytic oxidation of cyclohexane has important scientific research significance and application value in the field of heterogeneous catalysis. However, it is difficult for traditional catalytic systems to balance high conversion and high selectivity with convenient catalyst separation. In this study, Z-scheme WO3-Co3O4 composites are conceived and synthesized through controlled growth of Co3O4 square nanoparticles on WO3 nanorods for the boosted photo-thermo catalytic performance in the cyclohexane oxidation. The morphology structure, interface chemical bonding and photoelectrochemical properties of WO3-Co3O4 composites are investigated by various means of characterizations. The WO3-Co3O4 composites present significantly increased catalytic performance than WO3 nanorods and Co3O4 nanoparticles in the photo-thermo synergistic catalytic oxidation of cyclohexane under dry air. The high conversion rate of 11.46% with a KA oil selectivity of 99.12% was achieved using WO3-Co3O4 300 composite catalyst, which is 2.33 times that of WO3 nanorods and 1.24 times that of Co3O4 nanoparticles under the same catalytic conditions. The effect of reaction temperature and proportions of WO3-Co3O4 on the catalytic performances have been comparatively surveyed. Furthermore, energy band structure analyses and sacrificial trap experiments elucidate the Z-scheme charge transfer mode in WO3-Co3O4 composites to enhance the photo-thermo catalytic performance in cyclohexane oxidation.