Construction of hierarchical Prussian blue microcrystal with high sunlight absorption for efficient photo-thermal degradation of organic pollutants

Solar-driven photocatalysis is considered to be a green and efficient approach for organic pollutants removal, however improving solar utilization and conversion still faces great challenge. Herein, Prussian blue (PB) microcrystals with different morphologies including PB-cube, PB-flower and PB-ball are fabricated via a secondary-assembly strategy. PB-ball with hierarchical structure possesses more exposed crystal faces, more mesopores, and higher FeII content, rendering its higher catalytic efficiency for organic pollutants degradation. Besides, structured hierarchical morphology leads to higher and broader sunlight absorption, which efficiently improves photo-Fenton performance of PBs due to the higher photon utilization. More importantly, we demonstrate that PBs with photothermal conversion property largely promotes its Fenton reaction rate under solar irradiation, and PBs as nano heat source in the photothermal Fenton system can accelerate the substance diffusion, charge carrier movement, as well as active radical generation. Thus, coupling of photo-Fenton and photothermal of dual-function catalyst is an appealing strategy for organic pollutants removal.