Dual channel carrier transfer based on Ti3C2Tx improves carrier utilization of Z-scheme Ag3PO4/AgBr heterojunction photocatalyst

With high redox ability of electrons and holes, Z-scheme heterojunction is a promising composite structure in the photocatalysis. However, it is challenging to inhibit the recombination of carriers by Z-scheme transfer. Herein, a novel Ag 3 PO 4 /AgBr/Ti 3 C 2 Tx hybrid with dual channel carrier transfer structure was fabricated. Ti 3 C 2 Tx not only serves as a template for growth   of   Z-scheme   Ag 3 PO 4 /AgBr, but   also   can   be   used   to accommodate   holes   transferred   from Ag 3 PO 4 and AgBr. The first channel is consisted of Z-scheme transfer of carriers in Ag 3 PO 4 /AgBr. And the hole transfer from the AgBr valence band to Ti 3 C 2 Tx constitutes the second channel, which avoids directly carrier recombination in AgBr valence band. Dual channel carrier transfer pathway was proved by in situ irradiated X-ray photoelectron spectroscopy (ISI-XPS). After Ti 3 C 2 Tx was introduced, the quantum efficiency of Ag 3 PO 4 /AgBr increased from 10.59% to 12.50% with reducing Cr(VI), indicating an increase in carrier utilization. The improvement of the degradation efficiency of rhodamine B from 80.77% to 94.72% is benefited from the enhanced quantum efficiency. The dual channel carrier transfer heterojunctions design provides a new idea for constructing an efficient composite photocatalytic structure.