Synergistic CO₂ reduction and tetracycline degradation by CuInZnS-Ti₃C₂T_x in one photoredox cycle

Optimizing photocatalytic CO₂ reduction with simultaneous pollutant degradation is highly desired. However, the photocatalytic efficiency is restricted by the unmatched redox ability, high carriers’ recombination rate, and lack of reactive sites of the present photocatalysts. Herein, the CuInZnS-Ti₃C₂T_x hybrid with matched redox ability and suitable CO₂ adsorption property was rationally synthesized. The nucleation and growth process of CuInZnS was interfered by the addition of Ti₃C₂T_x with a negative charge, resulting in thinner nanosheets and richer reactive sites. Besides, the Schottky heterojunction built in the hybrid simultaneously improved the photoexcited charge transfer property, sunlight absorption range, and CO₂ adsorption ability. Consequently, upon exposure to sunlight, CuInZnS-Ti₃C₂T_x exhibited an efficient photocatalytic CO₂ reduction performance (10.2 μmol·h⁻¹·g⁻¹) with synergetic tetracycline degradation, obviously higher than that of pure CuInZnS. Based on the combination of theoretical calculation and experimental characterization, the photocatalytic mechanism was investigated comprehensively. This work offers a reference for the remission of worldwide energy shortage and environmental pollution problems.