Low-temperature deposition and crystallization of RuO2/TiO2 on cotton fabric for efficient solar photocatalytic degradation of o-toluidine

A green low-temperature deposition and crystallization method was developed to uniformly coat RuO2/TiO2 nanocomposite onto cotton fabrics for efficient solar photocatalysis. The sequential growth of anatase TiO2 and rutile RuO2 on the surface of the cotton was confirmed by XRD, Raman and XPS characterizations. After the deposition of RuO2, the optical properties of RuO2/TiO2/Cotton revealed better visible light absorption and higher charge mobility, and XPS spectra showed that the peaks of Ti 2p(3/2) and O 1 s shifted towards the lower binding energies due to the interfacial charge transfer at the robust RuO2/TiO2 mediated with Ti-O-Ru bonding. The photocatalytic performances of the RuO2/TiO2/Cotton were evaluated towards the photodegradation of o-toluidine (o-TD), an aromatic amine widely used in the chemical industry. Compared with TiO2/Cotton, RuO2/TiO2/Cotton exhibited a remarkable improvement in the photocatalytic activity. The presence of RuO2 on the surface of TiO2/Cotton narrowed the band gap and improved the absorption of visible light. Moreover, the successful formation of a robust heterogeneous interface between TiO2 and RuO2 suppressed the charge carrier (e(-)/h(+)) recombination effectively. With the RuO2/TiO2 coating chemically bound to the cotton fibers, RuO2/TiO2/Cotton delivered long-term stability in photocatalytic activity and high mechanical durability even after 20 washing times. Our facile and scalable synthesis strategy paved a universal route to efficient immobilization of visible-light-responsible TiO2-based photocatalysts on the low-heat-resistant substrates for various applications.