In situ fabrication of a thermally stable and highly porous conductive solar light-driven ZnO–CNT fiber photocatalyst

Abstract

A novel method to produce composite fiber photocatalysts consisting of ZnO nanoparticles and carbon nanotube fibers (ZnO–CNTFs) with high thermal stability and porosity was developed by catalyst-free recrystallization followed by thermal decomposition. The CNTFs were strongly bound to sheet-stacks of ZnO nanoparticles, and these sheet-stacks were shown to be highly porous. Oxygen vacancies in the ZnO nanoparticles play a role in the robust interactions between ZnO and the CNTFs. Several functional properties of the ZnO–CNTF composite were characterized: (a) electrical conductivity was measured to be 78 S cm⁻¹ and 139 S cm⁻¹ depending on the probe position, (b) thermal stability up to 875 °C, (c) photoactivity between 300 nm and 2100 nm, and a much stronger load bearing force than the pristine CNTFs. These enhanced mechanical, electrical, thermal, and optical properties of the ZnO–CNTF composite, as well as its radial breathing mode, were likely generated by the strong interactions between ZnO and CNTF. These enhanced characteristics lead to an excellent photocatalytic performance of the ZnO–CNTF composite under sunlight; the shorter degradation time (75 min), the high degradation percentage (97.6%), excellent recycle performance (93.5%) and number (12) with the amount (135 mg) to decompose methylene blue (100 mL, 0.25 mg mL⁻¹).