Honeycomb-like micro-mesoporous structure TiO2/sepiolite composite for combined chemisorption and photocatalytic elimination of formaldehyde

Structured hybrid materials based on the combination adsorbent-photocatalyst have large surface area, an average pore diameter, good dispersion and strong adsorptivity, showing promising performance for environmental applications. In this study, honeycomb-like micro-mesoporous structure TiO2/sepiolite composites were fabricated using TiCI4 and modified sepiolite (MS) nanofibers as the precursors by a hydrolysis-precipitation method. The effect of the textural, morphological and structural properties of TiO2/sepiolite composites on the adsorption and photocatalytic degradation of formaldehyde (HCHO) in gas phase was analyzed. The results indicate that thermal treatment at 550 degrees C and TiO2/MS weight ratios of 1/2 ensure an optimum combination of textural, optical and HCHO adsorption and photocatalytic properties. At ambient temperature, the optimal catalyst (relative humidity of 45%, and HCHO initial concentration of 6.56 mg/m(3)) could efficiently decompose HCHO into CO2 and H2O, and still showed a good performance even after 4 cycles under UV irradiation. The excellent performance of the TiO2/sepiolite is primarily ascribed to the synergistic effect between the adsorbability of sepiolite nanofibers and the catalytic ability of TiO2 nanoparticles. (C) 2017 Elsevier Inc. All rights reserved.