fig1

Figure 1. (A) Illustration of the band structures of commonly used semiconductors and the redox potentials of diverse reactants. Reproduced with permission from Ref^[9]. Copyright 2021, Wiley-VCH; (B) The principle of photocatalysis involves illumination (step 1), excitation of electrons from the valence band to the conduction band (step 2), charge separation and transportation to the reaction sites (step 3), surface reactions (step 4) and charge recombination on the surface (step 5). A, electron acceptor; D, electron donor; (C) Methane can be activated by different mechanisms photocatalytically. Reproduced with permission from Ref^[4]. Copyright 2022, Springer Nature.