Controllable Regulation of Ligand Stacking in MOF Single‐Crystal: From F‐F to E‐F Stacking Mode for Efficient Photocatalysis

Abstract Preparing single crystals of metal–organic frameworks (MOFs) is crucial for studying their semiconductor catalyst properties. In this study, Ni‐TBAPy‐EF (edge‐to‐face) single crystals are successfully synthesized in pure water for the first time and an effective strategy is proposed to promote the efficient utilization of photoexcited electrons by modulating the stacking mode of ligand in MOFs. The C─H∙∙∙π interactions between the ligands promote the formation of herringbone stacking and the Ni‐TBAPy‐EF can withstand a wide range of pH environments or organic reagents. Experimental results and theoretical calculations corroborate that the overlapping of intermolecular orbitals in this stacking mode enhance the light absorption capacity and charge transfer capability. The hydrogen bonding microenvironment and ligand‐metal charge transfer (LMCT) electron transfer in MOFs ensured efficient electron utilization. As a result, Ni‐TBAPy‐EF exhibites excellent hydrogen production (17.4 mmol g −1 h −1 , λ ≥ 420 nm) and high apparent quantum efficiency (AQE 9.16%) without co‐catalysts.