Quasi-type-II Cu-In-Zn-S/Ni-MOF heterostructure with prolonged carrier lifetime for photocatalytic hydrogen production

A CIZS/Ni-MOF heterojunction photocatalyst was constructed with a quasi-type-II band alignment, exhibiting prolonged carrier lifetime and efficient visible-driven hydrogen evolution through the synergy of abundant active sites and suitable energy platform of the bifunctional Ni-MOF. [Display omitted] •The bifunctional Ni-MOF nanosheets were employed to combine with CIZS QDs to construct a quasi-type-II heterostructure with prolonged charge carrier lifetime and abundant active sites.•The optimized hydrogen production rate of CIZS/Ni-MOF achieves 2642 μmol g−1h−1, 5.21 times to that of CIZS QDs.•The quasi-type -II band alignment facilitate the delocalization of the photogenerated electrons within CIZS QDs and Ni-MOF with close conduction band levels.•Further photoelectrochemical tests also gave a well-maintained photoluminescence and prolonged charge carrier lifetime in the CIZS/Ni-MOF heterostructure. Visible-driven photocatalytic hydrogen production using narrow-bandgap semiconductors has great potential for clean energy development. However, the widespread use of these semiconductors is limited due to problems such as severe charge recombination and slow surface reactions. Herein, a quasi-type-II heterostructure was constructed by combining bifunctional Ni-based metal–organic framework (Ni-MOF) nanosheets with BDC (1,4-benzenedicarboxylic acid) linker coupled with Cu-In-Zn-S quantum dots (CIZS QDs). This heterostructure exhibited a prolonged charge carrier lifetime and abundant active sites, leading to significantly improved hydrogen production rate. The optimized rate achieved by the CIZS/Ni-MOF heterostructure was 2642 μmol g−1 h−1, which is 5.28 times higher than that of the CIZS QDs. This improved performance can be attributed to the quasi-type-II band alignment between the CIZS QDs and Ni-MOF, which facilitates effective delocalization of the photogenerated electrons within the system. Additional photoelectrochemical tests confirmed the well-maintained photoluminescence and prolonged charge carrier lifetime of the CIZS/Ni-MOF heterostructure. This study provides valuable insights into the use of multifunctional MOFs in the development of highly efficient composite photocatalysts, extending beyond their role in light harvesting and charge separation.