In situ chloride-mediated synthesis of TiO2 thin film photoanode with enhanced photoelectrochemical activity for carbamazepine oxidation coupled with simultaneous cathodic H2 production and CO2 conversion to fuels

This study investigated the simultaneous photoelectrochemical (PEC) degradation of carbamazepine (CBZ), reduction of CO2 and production of H-2 using a TiO2 thin film as photoanode and Ag plate as cathode. The photoanode was fabricated using sequential hydrothermal and calcination processes. The use of chloride during the hydrothermal process enhanced formation of oxygen vacancies and defects on the TiO2 surface. Calcination not only further strengthened those features but also enhanced the crystallinity and anatase/rutile ratio, endowing the TiO2 photoanode with superior PEC capacity. Characterization of physicochemical and PEC properties revealed that photogenerated electrons-holes were rapidly generated and efficiently separated on the TiO2 surface during the PEC process. Hydroxyl radicals were the main active species responsible for anodic oxidation of carbamazepine, while hydrogen radicals and carbon dioxide radical anions mediated CO2 reduction and H-2 production in the cathodic process. This work confirms the suitability of the prepared TiO2 photoanode for PEC degradation of organic pollutants coupled with CO2 reduction and H-2 production.

Automated summary

This study successfully achieved the simultaneous photoelectrochemical degradation of organic pollutants, reduction of CO2, and production of H2 using a TiO2 photoanode. The use of chloride during the hydrothermal process enhanced the formation of defects on the TiO2 surface, while calcination further strengthened these features, improving the PEC performance of the TiO2 photoanode.