Green CQD-activated carbon heterostructures with enhanced visible light photocatalytic and antibacterial properties of Staphylococcus aureus from skin infections.

Developing sustainable multifunctional nanomaterials with efficient visible light driven photocatalytic and antibacterial performance remains a significant challenge for environmental remediation applications. Herein, garlic and ginger derived carbon quantum dots (CQDs) were successfully incorporated into activated carbon (AC) to fabricate CQDgar/AC and CQDgin/AC nanohybrids through a facile green synthesis approach. Structural, optical and morphological analyses confirmed successful formation of conductive CQDs/AC hetero interfaces with enhanced light harvesting and suppressed electron hole recombination. TEM analysis confirmed successful decoration of CQDs on the activated carbon surface while XPS verified surface chemical states and functional groups responsible for improved interfacial interactions. The enhanced charge-transfer characteristics were further supported by EIS confirming efficient interfacial electron transport. Optimized CQDgin/AC exhibited superior photocatalytic activity toward methyl orange degradation achieving 88.3% degradation after 5 h irradiation together with excellent recyclability over three consecutive cycles. The enhanced photocatalytic performance was attributed to efficient interfacial charge migration and reactive oxygen species (ROS) generation within the CQDs/AC heterostructure. Furthermore, azithromycin loaded CQDs/AC nanohybrids displayed enhanced antibacterial activity against Staphylococcus aureus where Azi-CQDgar/AC exhibited the highest inhibition zone of 24 mm due to synergistic oxidative and antibiotic mediated antibacterial effects. Overall, the developed CQDs/AC nano-hybrids provide a promising multifunctional platform for visible light assisted environmental and antimicrobial applications.