A review of carbon-based quantum dots for interfacial photocatalysis

• • C-QDs serve three distinct interfacial roles—electron sink, charge-transfer bridge, and microenvironment modulator—each requiring specific experimental validation such as transient absorption spectroscopy (carrier lifetimes) and in-situ FTIR for intermediate detection. • • In photocatalytic hydrogen evolution, C-QD-modified TiO2 achieved a hydrogen evolution rate of 12.3 mmol·h−1·g−1 under AM 1.5G illumination, a 4.2-fold enhancement over pristine TiO2, attributed to improved charge separation and reduced overpotential. • • For CO2 photoreduction, C-QD-decorated g-C3N4 exhibited a CO production rate of 28.7 μmol·g−1·h−1 with 96% selectivity, while maintaining stable performance over 10 consecutive cycles (loss <5%), underscoring the importance of interfacial engineering for product selectivity. • • In pollutant degradation via photo-enhanced AOPs, C-QD-based photocatalysts achieved 98.5% removal of methylene blue within 60 minutes under visible light (λ>420 nm), with a rate constant of 0.082 min−1, demonstrating practical viability for water treatment.