A hierarchical H3PW12O40/TiO2 nanocomposite with cellulose as scaffold for photocatalytic degradation of organic pollutants

Abstract

By applying the natural cellulose substance (e.g., ordinary laboratory filter paper) scaffold as the structural template, a series of nanotubular H3PW12O40/TiO2 (HPW/TiO2) composites with various contents of the H3PW12O40 component were fabricated, which perfectly inherited the hierarchically porous network structure of the original cellulose substance. The optimal HPW/TiO2 nanocomposite with a H3PW12O40 content of 15.6 wt% delivered an apparent rate constant of 0.54 min−1 towards the photocatalytic degradation of methylene blue (initial concentration: 10.0 mg L−1) under UV light, revealing an increment of 1.9 times in comparison with the pure TiO2 nanotubes sample. Moreover, when the cellulose scaffold was served as a support, the obtained HPW/TiO2/cellulose composite sheet exhibited excellent photocatalytic performance as a photocatalytic membrane for the photocatalytic degradation of organic pollutants directly under outdoor sunlight. Thanks to the three-dimensionally interwoven structures and the compact contact in-between the H3PW12O40 and TiO2 phases, the hierarchical HPW/TiO2 nanocomposites and the HPW/TiO2/cellulose composite sheet represented outstanding and recyclable photocatalytic performances. The possible photocatalytic mechanism was investigated to demonstrate that the photo-induced holes dominated the photocatalytic reaction.