Photocatalytic properties of aminated graphitic carbon dots based on citric acid

To design robust composite photocatalytic systems for hydrogen generation, efficient binding of the photoabsorber and the catalyst is critical. When using carbon dots as photoabsorbers, the efficiency of such binding can be easily controlled by varying their surface groups. In the present work, the structural and optical properties of graphitic as well as aminated graphitic carbon dots were prepared and investigated. The aminated carbon dots were obtained from the original citric acid-based by attaching dimethyl ethylenediamine and dimethylaminopropylamine molecules. The use of the obtained carbon dots as photoabsorbers in photocatalytic systems allowed us to establish the dependence of hydrogen generation on the charge and size of their surface groups. The analysis of the obtained experimental data showed that the use of dimethyl ethylenediamine molecules for amination of the carbon dots surface allows to enhance hydrogen generation by 2.7 times.