Lattice-matched controllable construction of nanometer scale CdS/TiO2 hollow nanoboxes Z-scheme heterojunctions based on micrometer and sub-nanometer CdS for comparison of visible photocatalytic activity

Size effect exerts a significant influence on the photocatalytic properties of materials. Nanometer CdS/TiO2 hollow nanoboxes (TiO2-HNBs) (tetragonal phase) Z-scheme heterojunctions were lattice-matched controllably fabricated by using cubic TiOF2 as a template and loading with micrometer CdS micron rods (hexagonal phase) or sub-nanometer CdS quantum dots (cubic phase) through one-pot template ultrasonic hydrothermal method. The morphology, constitution, physical property, as well as photocatalytic properties of as-prepared samples were investigated comprehensively. Under visible light irradiation (λ ≥ 420 nm), the hydrogen production rates of CdS micron rods, CdS nanorods/TiO2-HNBs (CT-7), CdS quantum dots/TiO2-HNBs (CTQ-7) and CdS quantum dots was 1642.61, 455.35, 148.92 and 1025.53 μmol/g/h, which was 26.39, 7.32, 2.39 and 16.48 times that of TiO2-HNBs, respectively. Meanwhile, the photodegradation rate of Rhodamine B by CdS micron rods, CT-7, CTQ-7 and CdS quantum dots within 60 min was 69.59%, 99.90%, 89.96% and 40.70%, which were 4.77, 6.85, 6.17 and 2.79 times that of P25, respectively. CdS micron rods had the largest size but the strongest photo-hydrogen production properties. Due to its Z-scheme heterojunction structure and Ti-S bond, CT-7 exhibited enhanced electron-hole separation rate and electron transfer rate, resulting in superior RhB degradation performance. Although CdS quantum dots had the smallest size, it did not boast the best performance, indicating that smaller size does not necessarily correlate with better photocatalytic performance. This study provides a reference for comparing the performance of photocatalytic materials with different sizes. [Display omitted] •CdS-based catalysts of different sizes were prepared by one pot template ultrasonic hydrothermal method.•It was found that the lattice of hexagonal phase CdS was more matched with tetragonal phase TiO2 compared to cubic phase.•A new method has been designed to construct Ti-S bonds in CdS/TiO2 Z-scheme heterojunction.•The prepared CdS-based catalysts demonstrated excellent photocatalytic hydrogen production and degradation performance.•This study found that the performance of catalysts is greatly affected by size and lattice-matched.