Green Carbon Dots (GCDs) for Photocatalytic Hydrogen Evolution and Antibacterial Applications

Microwave technique was used to synthesize Green Carbon Dots (GCDs) from Aloe vera leaves because of easy to apply, accessible, time-saving, cheap, safe and environmental-friendly way. The prepared GCDs/TiO2 composite was obtained via sensitization of TiO2 with the help of GCDs. The characterization of the GCDs/TiO2 was made optically, structurally and morphologically. The photocatalytic hydrogen activity of GCDs/TiO2 was investigated under visible light (λ>420 nm) irradiation in the aqueous solution using triethanolamine (TEOA) sacrificial electron donor. When Pt was used, GCDs/TiO2/Pt showed advanced hydrogen evolution production (1294 μmol g−1 h−1) approximately two-fold compared to GCDs/TiO2 (718 μmol g−1 h−1). In addition, NIR light-triggered antibacterial activity of GCDs on Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) were investigated by studying bacterial growth curve and abiotic GSH oxidation assay. GSH oxidation ability of GCDs was increased through NIR light irradiation. According to the bacterial growth curve test, E. coli was found to be more susceptible to our GCDs than S. aureus.