Hydrogel Based Nanocomposite Photocatalyst Containing In2S3/ g-C3N4 for Removal of Dye from Water

A novel resorcinol formaldehyde hydrogel-based matrix was synthesized to stabilize indium sulfide / graphitic carbon nitride (In2S3/ g-C3N4) heterojunction, and the adsorption performance and photocatalytic degradation activity of RhB over In2S3/ g-C3N4 in hydrogel were explored. The g-C3N4 nanosheets and In2S3 nanoparticles were synthesized and characterized by Fourier-transform infrared spectroscopy (FTIR), and UVVis diffuse reflectance spectroscopy (DRS). In2S3 and g-C3N4 were stabilized in hydrogel, and In2S3/ g-C3N4 in hydrogel was characterized by FFIR, DRS, X-ray diffraction, Brunauer-Emmett-Teller (BET) surface area analysiand Barrett-Joyner-Halenda (BJH) pore volume and pore size analysis, field emission scanning electron microscopy, and energy dispersive X-ray. The measured bandgap for In2S3/ g-C3N4 in hydrogel was 2.1 eV. BET results showed that the presence of heterojunction in the synthesis process of hydrogel dramatically increases the specific surface area about 20 times. In2S3/ g-C3N4 in hydrogel adsorbed RhB (25 ml of 3 ppm solution) about 72% and removed RhB under light irradiation about 89% in 120 min. The RhB removal reactions over In2S3/ g-C3N4 in hydrogel in both dark and under light irradiation conditions follow the first-order kinetic. This study reveals a new potential application of resorcinol formaldehyde hydrogel as a porous matrix to stabilize nano-size photocatalysts.