MOF-derived C, N-In₂O₃ with GdFeO₃ Z-scheme heterostructure for the photocatalytic removal of tetracycline

Metal oxides derived from metal–organic frameworks have received considerable attention for water treatment. Herein, MIL-68 (In)–derived rod-like carbon (C) and nitrogen (N) codoped In₂O₃–modified GdFeO₃ (CN–InO/GdF) Z-scheme heterostructures were rationally constructed through simple pyrolysis and a wet-chemical route. The synthesized CN–InO/GdF catalysts were characterized using several physicochemical techniques. Moreover, the obtained CN–InO/GdF exhibited excellent photocatalytic performance toward tetracycline (TC) degradation. Impressively, the optimized CN–InO/GdF-3 heterostructure catalyst displayed a boosted TC removal efficiency of 99.06% within 60 min of irradiation, which was 7.1 and 9.7 times higher than those of bare CN–InO and GdFeO₃, respectively. The remarkably enhanced photoactivity of CN–InO/GdF was principally attributed to the synergistically combined interfaces hindering the recombination of photoinduced carriers, and the maintained redox capacity via Z-scheme spatial charge transfer. Finally, the tentative degradation mechanism was determined on the basis of density functional theory calculations and intermediates analysis. This work elucidated the design of highly efficient catalysts for various applications.