Enhanced photocatalytic degradation of indoor formaldehyde by sepiolite decorated with TiO2 nanoparticles: Effects of key preparation parameters

In this study, natural sepiolite was employed as the support of TiO 2 for improving the photocatalytic degradation activity for indoor formaldehyde (HCHO) under solar light. The various TiO 2 /sepiolite composites were prepared to investigate the effect of TiO 2 loading amount and crystallization temperature on HCHO degradation performance. The composite with TiO 2 loading amount of 50% and 500 °C exhibited the optimal performance, whose mineralization rate was up to around 2.63 times higher than that of pure TiO 2 . The performance enhancement mainly resulted from the uniform deposition of TiO 2 with smaller grain size on sepiolite surface, leading to more exposed active sites, higher quantum efficiency and faster carrier separation efficiency. As a result, more active radicals were generated in composite thereby boosting the HCHO degradation performance. Overall, our study improve the understanding on the photocatalytic oxidation of HCHO by mineral-based photocatalyst , thereby promoting the practical application in indoor air purification.