Construction and Microenvironment Regulation of Short Charge Transfer Tunnel at MOF/COF Heterointerfaces for...

Raising electron transfer efficiency is a crucial issue in improving photocatalytic productivity. Herein, we propose a strategy for anchoring single atoms and the establishment of a short-distance electron transport pathway. By incorporating nitrogen-containing monodentate ligands into UIO-66-NH₂, Pt single atom could be co-anchored by both the nitrogen atom and the vacant Zr-oxo cluster. Subsequently, the Pt-containing UIO was condensed with TpPa-1. Thereby, a molecular-level electron transfer pathway from TpPa to Pt has been established at the heterointerface between TpPa and UIO. By rationally adjusting the positions of the functional groups (-H, -Cl, and -OCH₃) in the monodentate ligand, their involvement in the pathway was precisely regulated. They functioned as electron relays when positioned at the ortho-position of the amino group, thereby facilitating the electron delivery. Cl exhibited a more pronounced effect compared to OCH₃, UPT-o-Cl achieved the maximum H₂ yield of 14.21 mmol g^-1 h^-1. Mechanism calculations revealed that the groups located along the pathway would regulate the microenvironment of the constructed tunnels, resulting in a higher electron density and enhanced ability to adsorb H intermediates of the Pt sites. This research reports a strategy for precisely regulating the microenvironment adjacent to the active site, providing new insights into enhancing carrier mobility and utilization efficiency.