Sr2MgSi2O7: (Eu2+, Dy3+) decorated ultrathin g-C3N4: Improvement of spectrum conversion efficiency and realization of all-day-active photocatalysis

A novel all-day-active photocatalytic material g-C3N4/SMSO was synthesized by a one-step hydrothermal method in this study. The strongest wavelength of SMSO assisted phosphorescence is 465 nm and the excitation wavelength of g-C3N4 is 460 nm, which is a high spectrum conversion efficiency between them. Additionally, SMSO can be excited to generate electron holes under visible light to form type Ⅱ heterojunction with g-C3N4, which is beneficial to improve the catalytic performance. The best all-day-active catalytic effect was achieved with a mass ratio of g-C3N4 to SMSO is 5:6, and can be applied to a widely pH range (5–8). Finally, the possible photocatalytic degradation mechanism and pathway over g-C3N4/SMSO were proposed based on LC-MS analysis, DFT calculation and quenching experiments. The major reactive species for MB degradation over the g-C3N4/SMSO under visible light were ⋅O2−, ⋅OH and h+. When the external light source was removed, it seems that the ⋅OH and h+ played a noteworthy role.