“…from the (αhv)1/2 vs. photon energy (hv) plot ( Hou et al, 2020 ; Li et al, 2020d ; Wang et al, 2020a ; Zhang et al, 2020a ; Zhang Y. et al, 2020 ), the optical bandgap of chain g-C 3 N 4 and bulk g-C 3 N 4 was calculated to be approximate 2.88 and 2.93 eV, respectively. When the particle size descends to a certain value, the electron energy level near the Fermi energy level of the metal changes from quasi-continuous to discrete energy level ( Miao et al, 2019 ; Huang et al, 2020b ; Wu et al, 2020 ; Zhang S. et al, 2020 ), and the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital energy level (LUMO) of the nano-semiconductor particles have discontinuous energy gap, which leads to the blue shift of the chain g-C 3 N 4 .…”