Current perspectives of anodized TiO2 nanotubes towards photodegradation of formaldehyde: A short review

Abstract Recently, TiO2 nanotubes (NTs) has gained enormous research interest and the quest to enhance their photocatalytic properties and performance for the gaseous pollutants’ removal, especially formaldehyde continues. Several synthetic routes have been adopted for fabrication of TiO2 NTs. As the development in this area of research in nanotechnology nowhere seems to retard with increasing concerns due to the presence of toxic formaldehyde in indoor environment. The fabrication or synthesis approaches for growing TiO2 NTs are becoming more relevant than ever. In that aspect there is a dire need of critical assessment of the current perspective on synthesis routes and their ability to present a solution for the primary challenges of utilizing toxic solvents and expensive fabrication procedures and facilities. The present review gives a meaningful insight into the fabrication routes for TiO 2 NTs and highlighting the key finding from previous studies, thereby identifying the core challenges and strength of existing techniques. The state of the art is elaborated along with an all-inclusive review of the mechanism of formation of nanotubes and photodegradation of formaldehyde by TiO2 NTs. A group of emerging ionic-liquid based electrolyte known as deep eutectic solvents for TiO 2 NTs fabrication were identified as the potential electrolyte to overcome the limitations of the existing methods. Conclusive research needs in above mentioned aspects are suggested accordingly.