Perylene Tetracarboxylic Tetraester Sensitized Antimony Sulfide Composites for Photoelectrocatalytic Degradation of Methylene Blue Dye

The increase in population has led to an increase in the discharge of organic pollutants into the water environment. This work establishes a unified electrode testing platform to fairly compare photocatalysis (HP) and photoelectrocatalysis (PEC) over PTTE-Sb 2 S 3 heterostructure photoanode for methylene blue (MB) elimination. Unlike independent photocatalytic and PEC systems reported in most literature, all contrast experiments adopt identical catalyst loading amounts and electrode specifications, with applied bias as the only variable to reliably reveal the electric field synergistic effect. Owing to the unique advantages of PEC technology and the excellent properties of organic–inorganic heterostructures, the PEC/PTTE-Sb 2 S 3 system exhibits extremely high activity and stability in removing MB under visible light irradiation and achieves a relatively high degradation efficiency. The kinetic rate constants of the PEC/PTTE-Sb 2 S 3 system are approximately 14.6, 2.7, 2.5, and 2.1 times higher than those of the photolysis, photocatalysis (HP)/Sb 2 S 3 , HP/PTTE-Sb 2 S 3 , and PEC/Sb 2 S 3 systems, respectively. Radical quenching experiments confirm electrons (e − ), superoxide radicals (·O 2 − ), and hydroxyl radicals (·OH) are major active species. Combined with band structure analysis, we systematically differentiate the charge separation pathways of pure photocatalysis and PEC via band bending induced by external bias and propose a targeted degradation mechanism highlighting the unique electron extraction effect of the external electric field in PEC.