Doping of Chlorine from a Neoprene Adhesive Enhances Degradation Efficiency of Dyes by Structured TiO₂-Coated Photocatalytic Fabrics

Abstract

We demonstrate that using neoprene as a binder during the fabrication of TiO2-coated fabrics enhances the rates of photodegradation of dyes by the fabrics. The neoprene binder simultaneously modifies the surface of the TiO2 particles with Cl and dopes the TiO2 with Cl, without requiring high temperatures or other harsh laboratory treatments. The adsorption of chlorine on the surface and doping of the lattice with chlorine were confirmed by X-ray photoelectron spectroscopy. The chloride ions adsorbed onto the TiO2 surface introduces a negative surface charge that enhances electrostatic adsorption of cationic dyes, and greatly improves the self-sensitizing degradation performance of the dyes. Chloride ions replace lattice oxygen atoms in TiO2, inducing lattice oxygen vacancies, that reduce the apparent band gap of the TiO2 particles, enhancing its absorption of visible light, and further increasing the photocatalytic activity of the composite-coated fabric. The degradation rates of RhB and MB over 50 min were 95.2% and 96.0%, respectively. The degradation rate for MO reached 95.4% after 180 min. We also show that •OH and •O2− are active agents in the dye-degradation mechanism. Moreover, the photocatalytic performance of the composite-coated fabric was unchanged after eight cycles of photocatalytic degradation of RhB, demonstrating that the photocatalyst-coated fabrics was highly recyclable.

Keywords

• tio₂-coated fabrics
• self-sensitizing degradation
• neoprene
• chlorine doping
• oxygen vacancies