Enhanced oxidation ability in SnO₂/Pt-B-g-C₃N₄ towards 2,4-dichlorophenol removal

Heterostructure type and valence band (VB) and conductor band (CB) potential governs the redox ability of photocatalysts, in which enhanced oxidation is a key for phenol degradation. To increase the photocatalytic oxidation ability of catalysts, broad band gap SnO₂ was grown on Pt-decorated superior thin B-doped g-C₃N₄ (BCN) nanosheets for 2,4-dichlorophenol (2,4-DCP) removal. B-doped g-C₃N₄ nanosheets were created by a two-step thermal polymerization. Small Pt nanoparticles were grown on B-g-C₃N₄ nanosheets, in which B-doping resulted in the homogeneous distribution of Pt nanoparticles of 2-3 nm. These small Pt nanoparticles further supported the deposition of SnO₂ nanoparticles with small sizes of 4-7 nm and narrow distribution by solvothermal synthesis to create SnO₂/Pt/B-g-C₃N₄ heterostructures with well-developed interface and homogeneous component distribution. The much positive VB of SnO₂ improved the oxidation of photogenerated holes. These heterostructure catalysts revealed a 2,4-DCP t removal rate of 90.5 % at a concentration of 70 mg/L. The removal efficiency of 2,4-DCP was further increased in peroxydisulfate (PDS) system, and 2,4-DCP of 98 % was finally degraded. The well charge carrier transfer ability of SnO₂ and Z-scheme heterostructure formation with fine Pt nanoparticles decreased the photogenerated charge carrier recombination. The photocatalytic mechanism and degradation procedure of 2,4-DCP in PDS system were systemically discussed. The oxygen vacancies in SnO₂ components allow accelerated charge carrier transfer and promote the degradation of the pollutants. These results supply a utilizable way for improving the redox ability of catalysts and the application in pollution degradation in low-cost PDS-activated systems.