Effect of Al(OH)3 prepared from fly ash on the structural and catalytic properties of g-C3N4-based materials

In order to find the optimal combination method of secondary utilization of fly ash and graphite-phase carbon nitride (g-C3N4) modification, an efficient composite photocatalyst of gamma-Al2O3/g-C3N4 was obtained by calcining the composite precursors of Al(OH)(3)/ dicyandiamide (DCDA). The introduction of Al(OH)(3) prepared by combining fly ash into the precursors causes hydrogen-bonding interactions between Al(OH)(3) and DCDA, which facilitate the removal of N atoms from the edges of the CN framework of g-C3N4 during condensation, and the composites prepared possess more cyano defects. In addition, gamma-Al2O3 and g-C3N4 form a chemical bond at the interface, and this chemical bonding causes the density of the electron cloud in the vicinity of the N atoms to increase. Among them, the strongest chemical bonding between Al2O3 and g-C3N4 was observed in ACN-1, whereas the most cyanine defects were formed in ACN-1, which made ACN-1 exhibit the best photocatalytic degradation of methylene blue, which is 2.48 times higher than that of the pristine g-C3N4.