Facile and Controllable Modification of 3D In₂O₃ Microflowers with In₂S₃ Nanoflakes for Efficient Photocatalytic Degradation of Gaseous ortho-Dichlorobenzene

Novel 3D In 2 S 3 /In 2 O 3 heterostructures comprised of 3D In 2 O 3 microflowers and In 2 S 3 nanoflakes were synthesized via a facile hydrothermal process followed by an in situ anion exchange reaction. In the In 2 S 3 /In 2 O 3 heterostructures, the In 2 S 3 nanoflakes were in situ generated and uniformly assembled on In 2 O 3 microflowers. The microstructures, optical properties, oxygen vacancy concentration, and photoreactivity of the heterostructures could be tuned by adjusting the amount of sulfide source. The effect of In 2 S 3 -nanoflakes modification on the oxygen vacancy concentration, optical properties, charge carrier separation, and charge carrier lifetime of In 2 O 3 were investigated systematically. The catalytic activity of the proposed heterostructures for degradation of gaseous ortho -dichlorobenzene ( o -DCB, a representative chlorinated volatile organic compounds) was higher than that of either unmodified In 2 O 3 or TiO 2 (P25). Meanwhile, oxygen vacancies, systematically explored by Raman, X-ray photoelectron spectroscopy (XPS), and low-temperature electron spin resonance (ESR) spectroscopy, were demonstrated to have a two-side effect on the photocatalytic performance. Particularly, the main reaction products including o -benzoquinone type species, phenolate species, formates, acetates, and maleates were verified with in situ FTIR spectroscopy. Additionally, ESR examination confirmed that • OH and • O 2 – were the predominant reactive oxygen species involved in the degradation of gaseous o -DCB. The current research provides new insight into utilizing In-based heterostructures as promising and efficient visible-spectrum-responsive catalysts for the removal of harmful chlorinated volatile organic compounds.