Single-Atom Cobalt Decorated P-doped g-C3N4 for Efficient Visible-Light-Driven Water Splitting

Single-atom photocatalysts exhibit outstanding performance in energy and environmental photocatalysis, due to their exceptional capabilities in enhancing light-harvesting, charge transfer dynamics, and surface reactions. The key to preparing single-atom photocatalysts lies in developing an appropriate metal-support that can prevent aggregation or sintering during synthetic procedures. In this work, a Co(II)-urea complexe in-situ formed in melamine was employed as single-atom Co precursors to synthesize an efficient single-atom Co decorated P doped g-C 3 N 4 (Co/PCN) photocatalyst. The high-angle annular dark field transmission electron microscope (HAADF-TEM) results indicated abundant Co single atoms were immobilized in the g-C 3 N 4 matrix. Under visible-light irradiation, the as-prepared photocatalysts show remarkably enhanced photocatalytic performance. Especially, loaded with 1.5 wt% single atoms Co, the optimized Co/PCN exhibits H 2 evolution of 892.5 µmol g −1  h −1 , which is 33 times higher than that of PCN, and even twice as much as that of Pt-loaded g-C 3 N 4 (Pt/PCN). The enhanced photocatalytic activity is ascribed to the synergistic effect between single-atom Co and P doping, which facilitates efficient light harvesting, charge separation, and migration. It is believed that this study paves a new avenue for developing high-efficiency single-atom photocatalysts. Graphical Abstract