Construction of Ti3C2/ZnTCPP/CTFs Ohmic/S-scheme hybrid heterojunction with robust built-in electric field for boosting photocatalytic hydrogen evolution.

A heterostructure of Ti 3 C 2 /ZnTCPP/CTFs was constructed by the freeze-drying method and steam-assisted method. In visible light, the hydrogen evolution rate of Ti 3 C 2 /ZnTCPP/CTFs-3 was 6.2 times that of ZnTCPP, 4.4 times that of CTFs, 5.6 times that of Ti 3 C 2 /ZnTCPP and 1.7 times that of Ti 3 C 2 /CTFs. The hydrogen evolution rate of the optimized ternary composite reached 462.6 μmol·g−1·h−1, and the quantum efficiency at 420 nm was 3.34 %. At the same time, the ternary photocatalyst showed high stability. The strong S-type interfacial electric field promoted the separation of space charges between ZnTCPP and CTFs effectively. The two-dimensional Ti 3 C 2 nanosheets, as an Ohmic-junction H 2 -evolution co-catalyst, provided more electron transfer pathways and a large number of active sites for photocatalysis. This work provides some new ideas and enlightenment for the rational design of efficient Ohmic/S-scheme heterojunction photocatalysts. [Display omitted] • A Ti 3 C 2 /ZnTCPP/CTFs Ohmic/S-scheme heterojunction was reported for the first time. • The interfacial electric field between ZnTCPP and CTFs promoted charge separation. • Ti 3 C 2 promoted the separation and transfer of photogenerated electrons. • The S-scheme photocatalytic mechanism of the heterojunction was proposed. [ABSTRACT FROM AUTHOR]