The design and preparation of Mg and Zn co-doped carbon nitride with enhancing photocatalytic degradation efficiency for methylene blue

Carbon nitride (g-C 3 N 4 ) is a potential material that can be used for the treatment of the wastewater contains organic dyes. However, the photocatalytic efficiency of g-C 3 N 4 is limited by the wide band gap and fast recombination of photon-generated carriers. In this work, the co-doped with Mg and Zn of Mg Zn 0.07 -g-C 3 N 4 was designed and prepared to enhance the photocatalytic efficiency. The co-doped Mg and Zn shorted the band gap of g-C 3 N 4 from 2.74 eV to 2.50 eV. Interestingly, according to the DFT calculation, a Zn-bridge is formed between the interlayers of g-C 3 N 4 . The Zn-bridge reduces the electron localization and prolongs the existence time of photon-generated carriers. The as-prepared Mg Zn 0.07 -g-C 3 N 4 was applied for the photodegradation of methylene blue. The degradation ratios and photodynamic parameter of Mg Zn 0.07 -g-C 3 N 4 are higher than that of g-C 3 N 4 and Mg-g-C 3 N 4 (29.51 × 10 −3  min vs 8.00 × 10 −3  min).