Recent progress in the synthesis, characterization and photocatalytic application of energy conversion over single metal atoms decorated graphitic carbon nitride

Single-atom catalysts have attracted much attention because of their exceptional high activity, eminent atomic utilization, and good selectivity, exhibiting diverse performance in a wide range of energy conversion. However, with the decrease in particle size and sudden increase of surface energy, ultra-small particles may gather together to form nanoclusters and cannot maintain atomic scattering. Protecting catalytic sites requires normalizing and controlling the interaction between single atoms and substrates. Graphitic carbon-nitride, g-C₃N₄ with a unique two-dimensional (2D) structural unit and excellent stability, exhibits a controllable electronic structure that capable to be a support for the atomically dispersed metal atoms. Mainly, g-C₃N₄ contains many nitrogen atoms that are periodically detached and can attribute energetic positions for efficient constituents, primarily for single atoms. This review article introduced the synthetic approaches of single metal atoms (SMA) anchored g-C₃N₄, including synchronization atmosphere, electronic structures of SMA, and the latest characterizations towards their physiochemical applications. Solar energy conversion, including water splitting for H₂-production and CO₂-reduction using SMAs anchored g-C₃N₄, and the role of SMA in catalytic mechanism over the SMA modified g-C₃N₄ were discussed, along with the challenges and opportunities for further research into high-efficiency SMA-modified g-C₃N₄ photocatalysts. This review is estimated to explain the essentials and massive potential of SMAs anchored g-C₃N₄.