Highly customized porous TiO2-PANI nanoparticles with excellent photocatalytic efficiency for dye degradation

Abstract

The present work encompasses a simple strategy to synthesize highly porous TiO2 by incorporating PANI polymer into the sol-gel chemistry of Titanium dioxide/Titanium (IV)-iso-propoxide (TiO2/TTIP). A series of TiO2 samples by varying wt.% of PANI, have been synthesized. A probable growth mechanism has been presented for the formation of a porous ginger-like nanostructure of TiO2-PANI (TP). HRTEM images reveal that the particle size range is 6–16 nm for pristine TiO2 and 5–13 nm for TP samples. XPS analysis confirms the presence of the hydrogen bonds in-between surface hydroxyl groups (Ti–OH) of TiO2 and the protonated nitrogen of PANI. UV–visible absorption study reveals a small shift towards longer wavelength for TP8 sample than that of pristine TiO2 (λmax = 314 nm) as well as reduction in Eg value from 3.02 eV to 2.89 eV. FTIR results confirm the successful interaction of PANI and TiO2. BJH and BET analysis confirms an increase of porosity in TP8 sample with an average pore volume of 0.36 cm3 g−1. High photocatalytic activity (98.77%) towards Methylene blue dye degradation is observed for TP8 sample having 8 wt% of PANI and it is explained through the combined effect of structural porosity of TiO2 and synergic effect of PANI. The Kappa value at pH 11 (0.01372 min−1) is found to be 7.84-folds higher than that of the photocatalytic reaction at pH 3 (Kappa = 0.00175 min−1). While pristine TiO2 exhibits the minimum removal efficiency (89.57%) with Kappa of 0.00756 min−1. Kappa value of catalysis reaction for TP8 is found to be almost 2-fold higher than pristine TiO2. Quantum Yield value for TP8 is found to be 3.59 × 10−4 molecules photon−1. This high Quantum Yield value of present photocatalytic system explicates the low energy consumption for the treatment of textile dye pollutant. Additionally, STY value (1.79 × 10−5 molecules photon−1 mg−1) confirms the outstanding mineralization strength of TP8 by a unit mass for high amounts of MB dye per unit time. Thus, the present study offers an excellent photocatalyst i.e., TP8 having 8 wt% of PANI for the degradation of MB dye.