Ambient photothermal catalytic CO oxidation over a carbon-supported palladium catalyst

The XC-72R supported Pd catalysts exhibit low-temperature catalytic activity for CO oxidation under light irradiation. The CO conversion can reach 100% with the light irradiation of 900 mW·cm-2 at a catalyst temperature of 100 °C. Pd/C catalysts with different Pd loading have similar performance enhancement under light irradiation. The activation energy of 1% Pd/C catalyst remains unchanged implying that CO oxidation belongs to photothermal catalytic oxidation. The enhanced performance could be ascribed to ultrahigh surface temperature (275 °C) induced by the light irradiation of 800 mW·cm-2 and detected by an IR camera. That is higher than the catalyst temperature (187 °C) measured by the thermocouple. Carbon generates a higher temperature than Pd NP, causing heat transfers from carbon to Pd NP. In contrast, Pd NP produces a higher temperature than Al2O3 for Pd/Al2O3 catalyst, and heat is transferred from Pd to Al2O3. These demonstrate that the enhanced performance contributes to the photothermal effect of carbon.