Optimization of MoSe2 nanostructure by surface modification using conducting polymer for degradation of cationic and anionic dye: Photocatalysis mechanism, reaction kinetics and intermediate product study

In the present work, optimum nanocomposites of MoSe2-PANI (polyaniline) were successfully synthesized by modifying the surface of MoSe2 with PANI to enhance the photocatalytic efficiency. A series of MoSe2-PANI nanocomposites with different MoSe2 to PANI weight percent ratios (1:1, 1:2, 1:3 and 2:1) were prepared by insitu oxidative polymerization method to study the effect of variation of surface charge on photocatalytic efficiency. Samples were characterized using X-Ray Diffractometer (XRD), Field-Emission Scanning Electron Microscopy (FESEM), Fourier-transform infrared (FTIR) spectroscopy, Diffuse Reflectance spectroscopy (DRS), zeta potential measurements, Photoluminescence (PL) spectroscopy and time-correlated single photon counting (TCSPC). Comparative photocatalytic degradation of cationic dye (Rhodamine B) and anionic dye (Congo red) were performed. The mechanism of degradation was explained using active species trapping experiments. Intermediate products formed during the degradation process were determined using Liquid chromatography-mass spectroscopy (LC-MS). Reaction kinetics for the adsorption of dyes were also studied. MoSe2-PANI nanocomposite having MoSe2:PANI in 2:1 ratio showed the most significant charge separation and optimized surface charge for photocatalytic degradation of cationic and anionic dye.