Nano-sized aggregate Ti₃C₂-TiO₂ supported on the surface of Ag₂NCN as a Z-scheme catalyst with enhanced visible light photocatalytic performance

Exposing the photocatalyst's highly active facets and hybridizing the photocatalyst with suitable cocatalysts in the proper spot have been recognized as strong methods for high-performance photocatalysts. Herein, Ag₂NCN/TiO₂-Ti₃C₂ composites were synthesized by applying simple calcination and physically weak interaction deposition processes to obtain an excellent photocatalyst for Rhodamine B (Rh B) degradation when exposed to visible light. The findings from the experiments reveal that the Ag₂NCN/TiO₂-Ti₃C₂400 composite exhibited an outstanding photocatalytic rate in 80 min, with the highest Rh B degradation rate (k = 0.03889 min^-1), which was 16 times higher than that of pure Ag₂NCN (k = 0.00235 min^-1) and 2.2 times higher than that of TiO₂-Ti₃C₂400 (k = 0.01761 min^-1). The results from the following factors: (i) the powerful interfacial contact created by the in situ formation of TiO₂, and the superior electrical conductivity of Ti₃C₂ that makes carrier separation possible; (ii) TiO₂ with electron-rich (101) facets are deposited on the surface of Ag₂NCN, significantly reducing charge carrier recombination by trapping photoelectrons; (iii) a Z-type heterojunction is constructed between nanosize aggregate Ti₃C₂-TiO₂ and Ag₂NCN with non-metal Ti₃C₂ as the solid medium, improving the transfer and separation of photogenerated charges and inhibiting the recombination of electrons and holes. Additionally, the redox ability of the composite photocatalyst is enhanced. Furthermore, the analyses of active species showed that photogenerated superoxide radicals and holes were the principal active agents inside the photodegradation of Rh B. Moreover, the composite exhibited outstanding photo-stability.