Role of pore size on the photocatalytic dilapidation of organic pollutant SRB in mesoporous In2S3

Sulforhodamine B (C₂₇H₃₀N₂O₇S₂) (SRB) is a fluorescent dye commonly used for in-vitro cytotoxicity monitoring, which under standard conditions, does not undergo natural degradation and remains in water as such. We report on mesoporous In₂S₃ as an efficient photocatalytic agent for the degradation of this dye. Mesoporous In₂S₃ nanopowders were synthesized using a wet chemistry approach at a temperature of 30 °C. The synthesized nanopowders had preferential orientation along the (222) plane with an average crystallite size of ~ 4 nm. The pore size in the nanopowdered material was found to vary with the stoichiometry of the precursor solution. The photocatalytic degradation efficiency was found to vary with the pore size of the In₂S₃ nanopowder. The highest rate constant of 4.58 x 10^-3 min^-1 for SRB degradation was recorded for the sample with an average pore size of 1.79 nm. The mesoporous In₂S₃ demonstrates a degradation efficiency of ~ 91% under direct sunlight (~720 lux) and ~ 42.3% under the halogen light source (320 lux).

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