Photoelectrocatalytic hydrogen evolution and synchronous degradation of organic pollutants by pg-C₃N₄/β-FeOOH S-scheme heterojunction

Crafting photoelectrocatalytic materials with robust oxidation-reduction properties for simultaneous hydrogen evolution and pollutant degradation poses a formidable challenge. In this study, a pg-C₃N₄/β-FeOOH S-scheme heterostructure with a special energy band structure was developed by anchoring porous pg-C₃N₄ on needle shaped β-FeOOH. Functioning as a hole extraction layer, needle-leaf-like β-FeOOH can facilitate efficient hole migration and enhance charge transport. Remarkably, the optimized 0.2-pg-C₃N₄/β-FeOOH could degrade 78% of ofloxacin (OFLO) in 90 min. The organic pollutants could absorb a large number of holes, which prompted a greater proportion of photogenerated electrons to actively participate in the hydrogen evolution reaction at the cathode. Consequently, the hydrogen production of 0.2-pg-C₃N₄/β-FeOOH reached 1452.88 µmol cm⁻² h⁻¹, exhibiting a notable increase of 61.81–165.12 µmol cm⁻² h⁻¹ compared with that in the absence of pollutants. Experimental and theoretical calculation results underscore that this investigation is grounded in a distinctive electron and hole dual channel transfer mechanism. These findings offer novel insights for the future development of S-scheme heterojunction photoelectrocatalytic materials capable of concurrently degrading pollutants and promoting hydrogen evolution.