Separable and recyclable meso-carbon@TiO2/carbon fiber composites for visible-light photocatalysis and photoelectrocatalysis

Abstract

Recycle and reuse of the nanosized photocatalysts is a common challenge in the catalyst field. To address this issue, we rationally load meso‑carbon@TiO2 core-shell microspheres on carbon fiber felt to synthesize macro-sized meso‑carbon@TiO2/carbon fiber composites by an in-situ adsorption method. From the detailed microstructural and spectroscopic characterization, it has been found that the absorption edge of meso‑carbon@TiO2 core-shell microspheres is extended to the visible light region, and the recombination of photon-excited electrons and holes can be significantly suppressed when compared with P25 TiO2 powder. The experiment results of meso‑carbon@TiO2/carbon fiber composites indicates that the photocatalytic degradation rate under UV–vis light is much higher than that under visible light irradiation due to the higher charge carrier separation efficiency and the higher electron consumption of the direct Z-scheme. Moreover, the photocurrent density and the separation of photon-excited electrons from holes can be effectively promoted in the photoelectrocatalysis of meso‑carbon@TiO2/carbon fiber composites under visible light. The synergistic effect between electrocatalytic and photocatalytic oxidation under visible light results in almost complete degradation of Rhodamine B. Our study provides an avenue to recycle and reuse nanosized photocatalysts and open a possibility for practical industrial application of photocatalysis and photoelectrocatalysis using separable and recyclable meso‑carbon@TiO2/carbon fiber composites.