Representative non-noble metal SACs by the photochemical route. (A) Scheme of the synthesis of atomically dispersed metal single atoms. Solution A represents a metal salt solution and solution B represents a reducing solution. Reproduced with permission from ref. [103]. Copyright©2018, John Wiley and Sons. (B) Cu/BP and Co/BP structure synthesized by photoexcited radical reduction. Reproduced with permission from ref. [104]. Copyright©2022, Springer Nature.