Biomass-derived carbon quantum dots for ZnO photocatalysis: From precursor chemistry to mechanistic evidence and reporting standards
Year: 2026
Type: article
Abstract: Zinc oxide (ZnO) is an extensively explored photocatalyst whose practical application is constrained by rapid charge recombination and limited visible-light absorption. Biomass-derived carbon quantum dots (CQDs) have arisen as sustainable co-catalysts that enhance interfacial charge transfer, visible-light harvesting, and reactive oxygen species generation, while concurrently converting agricultural and food-processing waste. This review critically evaluates biomass-derived CQD/ZnO composites and introduces three analytical frameworks to improve mechanistic interpretation, reporting quality, and sustainability assessment. A comparative analysis reveals widespread under-characterisation across the literature, including limited reporting of quantum yield, fluorescence lifetime, mineralisation endpoints, ROS validation, and Zn leaching behaviour. Although hydrothermal synthesis dominates because of its simplicity and compatibility with biomass, substantial variation exists in process energy demand and mechanistic rigour. Nitrogen-doped CQD systems demonstrate enhanced electronic performance but also present unresolved trade-offs between photocatalytic efficiency and the credibility of green synthesis. Overall, this review argues that the principal limitation in biomass-derived CQD/ZnO composite systems is no longer material discovery itself, but the absence of standardised, mechanism-resolved reporting practices required for reliable cross-study benchmarking and reproducible interpretation.
Authors: D. Sivakumar, K. Rajammal
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,300
OpenAlex ID: W7204536307