Self-assembly of single-crystal ZnO nanorod arrays on flexible activated carbon fibers substrates and the superior photocatalytic degradation activity
Sha Luo, Chun‐Wei Liu, Yang Wan, Wei Li, Chunhui Ma, Shouxin Liu, Hero J. Heeres, Weiqing Zheng, K. Seshan, Songbo He
Abstract
The synthesis of one-dimensional nanocrystals on flexible substrates has attracted a great attention in the last decade. We here report an integrated approach using a sequential sol-gel and hydrothermal synthesis method to successfully assemble well-aligned single-crystalline wurtzite ZnO nanorod arrays (ZnO NRAs) on activated carbon fibers (ACFs). The ZnO NRAs, with high rod surface area (up to 20 m2 g−1), high aspect ratio (rod length/rod diameter, ca. 20:1) and high defect level (indicated by an extremely sharp blue emission, strong green and yellow emissions), were shown to grow nearly perpendicularly on the ACFs surface. The pre-coating of ZnO seed layers on ACFs surface during sol-gel synthesis is vital for the growth of the ordered ZnO nanorod arrays. The structural and optical properties of ZnO NRAs/ACFs can be adjusted by tuning the synthesis parameters for sol-gel and hydrothermal steps. As compared to the ZnO NRAs grown on the stiff substrates (e.g., silicon wafer, fluorine-doped tin oxide glass, GaN and metal sheets), ZnO NRAs grown on ACFs have very high surface area and intensive blue, green and yellow emissions. The novel ZnO NRAs/ACFs show excellent photocatalytic degradation of methylene blue and robust recyclability as compared to the individual ZnO nano particles (powder, NRs and NRAs).