Influence of g-C3N4 Precursors in g-C3N4/NiTiO3 Composites on Photocatalytic Behavior and the Interconnection between g-C3N4 and NiTiO3

In this study, composite photocatalysts were produced from NiTiO 3 and N 2 -rich precursors (dicyandiamide, melamine, urea, and thiourea) under N 2 flow conditions. The goal of the study was to investigate the interaction between NiTiO 3 and the synthesized g-C 3 N 4 . The properties of the g-C 3 N 4 /NiTiO 3 (CNT) composites were different depending on the starting materials. Dicyandiamide and thiourea created strong connections with NiTiO 3 and resulted in the generation of Ti–N and Ti–O–S bonds. Urea and melamine, however, had difficulty forming g-C 3 N 4 structures or interconnections with NiTiO 3 . The Ti–N and Ti–O–S bridges in the composite photocatalysts led to increased photocatalytic activity as well as inhibition of the recombination rate. Additionally, the band diagrams of g-C 3 N 4 prepared from dicyandiamide and thiourea exhibited positions suitable for the Z-scheme charge-transfer model with NiTiO 3, implying that the composite photocatalysts were applicable for photocatalytic degradation of organic contaminants under the visible-light irradiation. Higher reaction rate constants for the composites prepared with dicyandiamide and thiourea confirmed the significant role of the Ti–N/Ti–O–S bridge between g-C 3 N 4 and NiTiO 3 .