1D/2D In2O3/g-C3N4 S-scheme heterostructure for enhanced photocatalytic degradation of tetracycline hydrochloride: Interfacial charge transfer mechanism, degradation pathways, and toxicity assessment

S-scheme In 2 O 3 /g-C 3 N 4 heterostructure was prepared for tetracycline hydrochloride (TCH) degradation through in-situ growth of In 2 O 3 nanorods (NRs) onto g-C 3 N 4 nanosheets (NSs) via high-temperature thermal polymerization method. The results show that resulted heterostructure could exhibit varying photocatalytic behaviors under simulated sunlight depending on In 2 O 3 loading ratios. The one with loading ratio of In 2 O 3 to g-C 3 N 4 at 10 wt% could display the best photocatalytic performance with efficiency up to 93.4% within 60 min, which are 2.61-fold and 1.17-fold higher than In 2 O 3 and g-C 3 N 4 . Herein, In 2 O 3 and g-C 3 N 4 components with matched band structures could individually serve as holes quencher and electrons donor to prolong carrier lifetime through in-situ formed interfacial electrostatic field due to their different Fermi levels. An S-scheme heterostructure could thus be engineered to facilitate charge carrier migration while enhancing redox capabilities, ultimately yielding superior photocatalytic performance. Moreover, the developed heterostructure could present superior structure and activity stability. Crucially, it was noticed that • O 2 – and • OH radicals played a major role in TCH degradation and the possible degradation and mineralization pathways as well as toxicity of by-products were explored based on identified intermediate products. These findings underscore that In 2 O 3 /g-C 3 N 4 heterostructure could hold substantial potential for practical environmental remediation applications.