All-in-one transparent cellulose-based composite membrane for simultaneous colorimetric detection and photocatalytic degradation of amine VOCs

Developing high-performance multifunctional catalyst that adept at both sensitive detecting and efficient degrading of volatile organic compounds (VOCs) is of significant importance for human and eco safety. This work presented a bifunctional nonmetal composite membrane by functionalizing transparent cellulose membrane with double responsive bromocresol green and catalytic g-C 3 N 4 /COF TAPB-PDA (CNC) heterojunctions for simultaneous detection and degradation of amine VOCs. Bromocresol green possesses both intrinsic visualized acid-base responsiveness and wide light adsorption range. Hierarchical CNC with high specific surface area (up to 1256.60 m 2 g −1 ) can effectively promote the absorption and diffusion of substrates and the separation of photo-generated carriers. A flexible macroporous transparent cellulose membrane was applied as carrier to alleviate the “self-masking effect” of the catalyst inside to improve light utilization. As a result, the composite membrane showing a visually reversible color change from yellow to blue for amine VOCs and achieving rapid quantitative detection of representative triethylamine (detection time of 5 s with a LOD of 0.32 ppm) on the aid of a smart phone. The degradation and mineralization efficiency of triethylamine reached 97.3 % and 73.5 % within 180 min, respectively. The ingenious design of integrating bifunctional cellulose composite material provides feasibility for the rapid identification and efficient removal of VOCs.