Photocatalytic exoskeleton: Chitin nanofiber for retrievable and sustainable TiO2 carriers for the decomposition of various pollutants

Abstract

Loading a photocatalytic TiO2 to organic carriers has been desired for volumetric TiO2 incorporation, facile retrieval, and sustainable utilization. Traditionally, suspended TiO2 nanoparticles or its thin film on two-dimensional substrate are popularly fabricated for pollutants decomposition without carriers; due to poor thermomechanical properties of the organic carriers. Herein, a combination of the chitin nanofiber carrier and atomic layer deposition proves relevance for formation of anatase TiO2 thin layer so that photocatalytic decomposition in three-dimensional surface. Moreover, chitin nanofiber is capable of holding the TiO2 nanoparticles for multiple cycles of photocatalysis. Those types of TiO2 show characteristic degradation performance for gaseous (acetaldehyde) and aqueous pollutants (4-chlorophenol and rhodamine B). After catalytic reaction, chitin/TiO2 is retrievable owing to carrier's robustness even in water without TiO2 aggregation and loss. This work suggests that chitin-based photocatalyst is applicable to numerous pollutants through chitin's relatively high chemical resistance and stably wedged TiO2 during photocatalytic reaction.