Microwave-assisted synthesis of carbonized polymer dots/CdS quantum dots/Bi2WO6 Z-scheme heterojunctions: Enhancing photocatalytic environmental remediation via dual-quantum dot heterostructures

Bing Shen; Yukun Chen; Li Zhao; Wenwen Qu; Han Xiao; Shu Yang

doi:10.1016/j.jcis.2025.01.023

Microwave-assisted synthesis of carbonized polymer dots/CdS quantum dots/Bi₂WO₆ Z-scheme heterojunctions: Enhancing photocatalytic environmental remediation via dual-quantum dot heterostructures

J Colloid Interface Sci. 2025 Jan 6;684(Pt 1):226-243. doi: 10.1016/j.jcis.2025.01.023. Online ahead of print.

Authors

Bing Shen¹, Yukun Chen¹, Li Zhao¹, Wenwen Qu², Han Xiao¹, Shu Yang¹

Affiliations

¹ Faculty of Science, Kunming University of Science and Technology, Kunming 650500, China.
² Faculty of Science, Kunming University of Science and Technology, Kunming 650500, China; Key Laboratory of Unconventional Metallurgy, Ministry of Education, Kunming University of Science and Technology, Kunming 650093, China. Electronic address: qwwen1977@126.com.

PMID: 39793430
DOI: 10.1016/j.jcis.2025.01.023

Abstract

The fabrication of dual-quantum dot heterostructures offers a promising strategy to enhance the environmental remediation performance of photocatalysts. Herein, a Bi₂WO₆-based Z-scheme heterojunction was constructed by incorporating carbonized polymer dots (CPDs) and CdS quantum dots (QDs) via a microwave-assisted solvothermal method. The 1 wt% CPDs/CdS QDs/Bi₂WO₆ (CCBW-1) composite achieved optimal Cr(VI) removal, reaching 97.7 % within 30 min under 10 W LED light, with rate constants 4.4, 2.8, and 10.1 times higher than those of pristine Bi₂WO₆, CdS QDs/Bi₂WO₆, and 3 % CPDs/Bi₂WO₆, respectively. Notably, the composite also demonstrated 96.9 % Cr(VI) and 98.1 % Rhodamine B (RhB) removal within 30 min in a mixed Cr(VI) and RhB solution. The formation of strong BiS and WOCd bonds at the Bi₂WO₆CdS QD interface facilitates intimate interfacial contacts and creates atomic-scale "highways" that accelerate charge transfer. Additionally, the electron-donating effects of the NH₂ and OH functional groups on the CPDs further enhance carrier transfer efficiency. The Z-scheme electron transport pathway enables CCBW-1 to capitalize on the deep reduction potentials and extended light absorption of the dual-QDs, allowing them to act synergistically as active centers. By integrating experimental data with theoretical calculations, the photocatalytic mechanism, potential intermediates, photodegradation pathway, and biological toxicity were comprehensively elucidated.

Keywords: Atomic contact; Carbonized polymer dots/CdS quantum dots/Bi(2)WO(6) composite; Dual-quantum dot heterojunction; Microwave-assisted synthesis; Synergistic Cr(VI) and RhB removal.