Hydrothermal synthesis and efficient production of H2O2 using Bi2MoO6 photocatalyst subject to carbon quantum dots loading

• Published in: Diamond and related materials Vol. 154; p. 112249
• Main Authors: Wang, Qishen, Chen, Changzhao, Li, Mengqing, Gao, Juan, Zheng, Lingcheng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2025
• Subjects: Bi2MoO6 (BMO); Carbon quantum dots (CQDs); H2O2 production; Photocatalysis; Carbon quantum dots (CQDs); Bi2MoO6 (BMO); Photocatalysis; H2O2 production
• ISSN: 0925-9635
• DOI: 10.1016/j.diamond.2025.112249

Carbon quantum dots (CQDs) have emerged as promising co-catalysts in photocatalysis owing to their superior light-harvesting capabilities, tunable surface chemistry, and eco-compatibility. This work demonstrates a rationally designed CQDs/Bi2MoO6 (BMO) composite material synthesized via hydrothermal methods for solar-driven hydrogen peroxide (H2O2) production. By precisely optimizing CQDs loading ratios, the composite achieves an 11.75-fold enhancement in H2O2 generation rate compared to pristine BMO within 2 h, while maintaining 94.66 % activity retention over multiple cycles. Systematic characterization reveals three synergistic mechanisms: 1) CQDs broaden visible-light absorption through antenna effects and facilitate interfacial charge separation via Schottky junctions; 2) Optimized energy band alignment between CQDs and BMO simultaneously satisfies thermodynamic requirements for oxygen reduction (ORR: O2 → H2O2) and water oxidation (WOR: H2O → O2) reactions; 3) Abundant edge-active sites on CQDs promote *OOH intermediate stabilization during H₂O₂ formation. Notably, the study identifies a critical CQDs loading threshold (6 wt%) beyond which excessive surface coverage induces carrier recombination and disrupts reaction interfaces, causing performance decline. These findings establish a quantitative structure-activity-stability relationship for hybrid photocatalysts, addressing longstanding challenges in balancing co-catalyst dispersion and functional integrity. The work not only provides fundamental insights into interfacial engineering of quantum dot-semiconductor systems but also proposes a scalable synthetic strategy for robust solar-to-chemical conversion technologies. [Display omitted] •Hydrothermal CQDs/BMO enables green solar-driven H2O2 production.•CQDs/BMO shows 11.75× rate vs BMO; 94.66 % stability.•CQDs boost light absorption, charge separation & ORR/WOR alignment.•Excess (>6 wt%) causes interface saturation & band distortion, lowering efficiency.