Construction of Z-scheme tungsten trioxide nanosheets-nitrogen-doped carbon dots composites for the enhanced photothermal synergistic catalytic oxidation of cyclohexane

The novel Z-scheme WO3 nanosheets-carbon dots (CDs) composites were prepared by assembling carbon dots with different terminal groups of amine groups and carboxylic acid groups on the surface of WO3 nanosheets. Their microtopography, structural composition, optical and electrochemical properties are further compared. The lower fluorescence intensity and interfacial resistance of WO3-N-doped carbon dots (NCDs) composites indicate the efficient electron transfer between the two semiconductors. The WO3-NCDs composites show the significantly improved photothermal catalysis activity of cyclohexane oxidation with the highest conversion of 7.88% and selectivity to KA oil of 98.9%. This performance is 1.2 times that of WO3-carbon dots with the carboxyl groups (CCDs) composites and 1.5 times that of pure WO3 nanosheets. The significantly increased catalytic performance was caused by the effective Z-scheme charge transfer between NCDs and WO3, and the accelerated chain initiation of cyclohexane oxidation by the photothermal synergistic catalysis.