Growth of TiO2 nanorod bundles on carbon fibers as flexible and weaveable photocatalyst/photoelectrode

Abstract

Semiconductor photocatalysis technology has great potential to become one of the most promising solutions for energy shortages and environmental pollution, and a prerequisite for the photocatalytic application is to obtain efficient, easily recyclable and large-area photocatalysts with nanostructures. In the present work, we have prepared TiO₂ nanorod bundles on carbon fibers as flexible and weaveable photocatalyst/photoelectrode. The growth of TiO₂ nanorod bundles is realized by using a dip-coating and hydrothermal growth method. TiO₂ nanorod-bundles exhibit square-column appearance with size of about 340–400 nm and length of ∼6 μm, and they are in fact composed of small nanorods with diameters of ∼30 nm. Subsequently, 16 bunches of CFs with TiO₂ nanorod bundles can be weaved to be a macroscale CFs/TiO₂ cloth (weight: 0.2 g, total area: ∼35 cm²) with excellent conductivity and flexibility. With CFs/TiO₂ cloth as the working electrode, photoelectrochemical measurements demonstrate that the separation of photo-induced charge carriers can be improved by increasing the applied voltage bias. Furthermore, under the illumination of simulated solar light, CFs/TiO₂ cloth can degrade 94.0% Rhodamine B (RhB) in 100 min by photoelectrocatalytic degradation process (bias: 0.6 V vs. SCE), which is higher than the efficiency from single photocatalysis (60.8% RhB) or electrocatalysis (5.6% RhB) process. In addition, CFs/TiO₂ cloth can be easily recycled with good performance stability. Therefore, this kind of CFs/TiO₂ cloth can be used as a promising, easily recyclable and large-area photocatalyst/photoelectrode in practical application (such as degrading organic pollutants in lake and/or river). More importantly, this work provides some insights into the design of efficient and macroscale photocatalyst/photoelectrode with other nanosized semiconductor for enhancing visible-light-driven photocatalytic activity.