Ligand bridged MXene/metal organic frameworks heterojunction for efficient photocatalytic ammonia synthesis

Abstract

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 Ti3C2Ox and MIL-125(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 Ti3C2Ox through this ligand-bridge. This effectively reduced the interface charge transfer resistance, enhanced the separation efficiency of charge carriers. Consequently, the Ti3C2Ox/MIL-125(Ti) manifested an excellent ammonia evolution rate of 103.02 μmol·gcat-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.