Carbon cloth core with a PEDOT decorated TiO2 shell for degradation of emerging organic contaminants and enhanced vanadium redox flow batteries

Abstract

In this study, carbon cloth (CC) was enrobed with a TiO₂ layer (CC@TiO₂) and then decorated with poly(3,4-ethylenedioxythiophene) (PEDOT, CC@TiO₂-PEDOT). The XRD, Raman, XPS, and EDS results confirmed the successful preparation of the targeted materials, and SEM images revealed the targeted morphology. According to the UV–vis and PL analysis, the CC@TiO₂-PEDOT exhibits wide and strong photoabsorption across the UV–vis spectrum, and the photogenerated charge carriers have a long lifespan and low recombination rate. The photocatalytic assessment revealed that CC@TiO₂-PEDOT was more efficient than CC@TiO₂ and CC@PEDOT in degrading both benzotriazole and 2-hydroxybenzothiazole. However, 2-hydroxybenzothiazole was more stable than benzotriazole. The superoxide anion radicals, holes, and/or hydroxyl radicals of CC@TiO₂-PEDOT played pivotal roles in the photocatalytic degradation of benzotriazole. After the photocatalytic process, the benzotriazole solution was safe to use. The CC@TiO₂ and CC@TiO₂-PEDOT exhibited a superior performance as a potential cathode for vanadium redox flow batteries (VRFBs) and effectively mitigated the parasitic influence of the hydrogen evolution reaction (HER). CC@TiO₂ and CC@TiO₂-PEDOT displayed significantly smaller peak separation of 94 and 62 mV, at a scan rate of 5 mV/s, respectively, and a higher suppression for HER compared to CC or CC@PEDOT. The performance of the CC@TiO₂ and CC@TiO₂-PEDOT electrodes manifests their high reversibility for the V(II)/V(III) redox reaction. This research underscores the multifaceted potential of CC@TiO₂-PEDOT as a promising material for addressing water purification challenges and advancing VRFBs for sustainable energy applications.