Photothermal catalytic oxidation of toluene by perovskite oxide/biochar nanocomposite: Effect of biomass incorporation

The utilization of waste biomass for the development of full-spectrum response photothermal catalysts shows significant potential in catalytic oxidation of volatile organic compounds (VOCs). Herein, perovskite oxide LaCoO3/biomass-derived biochar nanocomposite was synthesized by the sol–gel method using wasted pomegranate peel as complex agent. The introduction of biomass resulted in improved dispersion of LaCoO3 particles and enhanced the adsorption of toluene attributed to the large specific surface area and rich functional groups of biochar. Furthermore, the biochar exhibited strong broadband absorption and efficient photo-thermal conversion under light illumination, which not only activated the lattice oxygen on the surface to react with toluene, but also increased the transmission rate of photogenerated charge carriers. The defects of LaCoO3 caused by carbon doping facilitated the circulation of oxygen species, leading to the generation of more reactive oxygen species. When the mass ratio of LaCoO3 to biomass was 1:0.6, the LaCoO3/biochar composite exhibited excellent photothermal catalytic performance with a T90 value of 270 °C (temperature at 90 % degradation) and displaying high stability. Moreover, In-situ DRIFTS analysis revealed that both adsorbed oxygen and lattice oxygen participated in the reaction with toluene, promoting the ring-opening reaction of toluene and subsequent conversion of intermediates.