Enhanced photocatalytic degradation activity of titanium dioxide by adsorbing aromatic amines through N-bonding

Abstract

Narrowing the wide band gap of TiO₂ (∼3.2 eV) to enhance its visible light efficiency is crucial for advancing photocatalytic degradation of organic pollutants in industrial wastewater. In this study, we achieved band gap reduction and slowed recombination rates by adsorbing some aromatic amines, like aniline and its electron-donating derivatives, onto TiO₂. The predominantly present N-bonded amine species reduced the band gap and decelerated charge carriers’ recombination, enhancing photocatalytic degradation under visible light. In contrast, the amine with electron-withdrawing group is adsorbed as only H-bonded species, which showed no improvement in photocatalytic activity, performing similarly to pristine TiO₂. This surface modification strategy offers potential for creating visible light-driven photocatalysts for effective degradation of organic pollutants in water.