Ligand Bridged MXene/Metal Organic Frameworks Heterojunction for Efficient Photocatalytic Ammonia Synthesis

Efficient interfacial charge transfer is imperative for enhancing N₂ photofixation, yet controlling this process proves challenging. Herein, a unique ligand pre-coupling strategy was employed to design ligand-bridged MXene/MIL-125(Ti), creating a coordination bond between Ti₃C₂O_x and MIL125(Ti) and forming a ligand-bridge, aiming to regulate interfacial electron transfer. Kelvin probe force microscopy and charge density difference analysis revealed the establishment of an electronic unidirectional transport channel from MIL-125(Ti) to Ti₃C₂O_x through this ligand-bridge. This effectively reduced the interface charge transfer resistance, enhanced the separation efficiency of charge carriers. Consequently, the Ti₃C₂O_x/MIL-125(Ti) manifested an excellent ammonia evolution rate of 103.02 μmol·g_cat^-1·h^-1. Furthermore, the efficiency of this strategy for accelerating the separation of photogenerated carriers was demonstrated in five other MOFs, demonstrating its potential for constructing ligand-bridged MXene/MOFs heterojunctions.