One-pot annealing preparation of Na-doped graphitic carbon nitride from melamine and organometallic sodium salt for enhanced photocatalytic H2 evolution

Na-doped graphitic carbon nitride was successfully developed by a one-pot preparation, that was, by simply annealing the mixture of melamine and organometallic sodium salt (ethylenediamine tetraacetic acid disodium salt). Visible-light-driven photocatalytic H2-evolution activity of graphitic carbon nitride was effectively enhanced by Na doping (9.2 times). It was found based on comprehensive analysis that, the absorption of visible light was improved due to the structural change of graphitic carbon nitride by Na doping, thereby promoting the generation of more photo-generated carriers. Meanwhile, the separation and transfer of photo-generated carriers were greatly enhanced by coordination of Na into big C-N rings of the triazine units. Moreover, more active sites for photocatalytic H2-evolution reaction were provided by the increased surface areas.