PAMAM templated N,Pt co-doped TiO2 for visible light photodegradation of brilliant black

Abstract

This study examined the photocatalytic degradation of an azo dye brilliant black (BB) using non-metal/metal co-doped TiO₂. N,Pt co-doped TiO₂ photocatalysts were prepared by a modified sol-gel method using amine-terminated polyamidoamine dendrimer generation 0 (PG0) as a template and source of nitrogen. Structural, morphological, and textural properties were evaluated using scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy (SEM/EDX), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR), Raman spectroscopy (RS), photoluminescence (PL) and ultra-violet/visible spectroscopy (UV-Vis). The synthesized photocatalysts exhibited lower band gap energies as compared to the Degussa P-25, revealing a red shift in band gap towards the visible light absorption region. Photocatalytic activity of N,Pt co-doped TiO₂ was measured by the reaction of photocatalytic degradation of BB dye. Enhanced photodegradation efficiency of BB was achieved after 180-min reaction time with an initial concentration of 50 ppm. This was attributed to the rod-like shape of the materials, larger surface area, and enhanced absorption of visible light induced by N,Pt co-doping. The N,Pt co-doped TiO₂ also exhibited pseudo-first-order kinetic behavior with half-life and rate constant of 0.37 and 0.01984 min^-1, respectively. The mechanism of the photodegradation of BB under the visible light irradiation was proposed. The obtained results prove that co-doping of TiO₂ with N and Pt contributed to the enhanced photocatalytic performances of TiO₂ for visible light-induced photodegradation of organic contaminants for environmental remediation. Therefore, this work provides a new approach to the synthesis of PAMAM templated N,Pt co-doped TiO₂ for visible light photodegradation of brilliant black.

Keywords: Dendrimer; N,Pt co-doped TiO2; Nanomaterials; PAMAM-NH2; Photodegradation; Visible light.