Synergistic photothermal catalytic oxidation of methanol and toluene mixture over Co-MOFs-derived catalyst: Interfacial and promotion effects

Abstract

Herein, a series of Co/CoOx@CN nanocomposites with tunable synergistic interfacial structure were successfully obtained by a facile pyrolysis treatment. Among these nanocomposites, the nanocomposite pyrolyzed at 500 °C (denoted as Co/CoOx@CN-500) exhibited the best methanol photothermal catalytic activity (97% methanol conversion and 96% CO2 yield) under simulated solar irradiation. Compared with Co nanoparticles and Co@CN, Co/CoOx@CN-500 showed higher methanol photothermal catalytic activity. Moreover, the Co/CoOx@CN-500 also displayed a good ability to degrade methanol under outdoor natural solar. Such excellent photothermal activity mainly benefited from the strong interaction between the metals Co, CoOx and graphitic-carbon, which enhanced the photothermal effect by inducing the high work temperature, and the surface adsorb oxygen species of Co/CoOx@CN-500. Besides, the promotion effect of methanol on toluene oxidation was observed over Co/CoOx@CN-500 for the photothermal catalytic oxidation of the methanol and toluene mixture relative to their individual component. Water molecules did not affect the promotion effect of methanol on the photothermal catalytic oxidation of toluene. Reaction mechanism studies showed that 2-methylbenzaldehyde, the key intermediate formed by the reaction of formaldehyde generated by methanol oxidation and toluene, is the main reason for the improvement of the oxidation activity of toluene.