Biomass-assisted synthesis of long-rod TiO2 with oxygen vacancies active sites and biomass carbon for efficient photocatalytic reduction of Cr(VI) under visible light

Abstract

Biochar-based materials have conventionally served as effective agents for Cr(VI) removal, predominantly through adsorption. However, the conversion of Cr(VI) to Cr(IIl) stands as a more favorable remediation approach. Herein, we present the synthesis of biomass carbon-modified TiO2 photocatalysts enriched with oxygen vacancies, employing a dual-purpose strategy to address both objectives simultaneously. Utilizing aloe biomass not only facilitated the generation of elongated TiO2 rods but also introduced biochar and oxygen vacancies. The resulting catalysts demonstrated exceptional efficiency in Cr(VI) reduction, achieving nearly complete removal (approaching 100 %) within a mere 5-minute duration under visible light irradiation. The strategic integration of surface oxygen vacancies and biochar onto TiO2 notably broadened the absorption spectrum, effectively harnessing sunlight. Furthermore, biochar's functionality extended to facilitating electron transfer and acting as an electron reservoir, collectively mitigating electron-hole pair recombination. This study delineates a pioneering tactic for the robust reduction of Cr(VI) pollutants, offering substantial promise in advancing.