Directed charge transfer over GM/UiO-66 ternary heterojunction for enhanced photocatalytic nitrogen fixation

This study presents a rational construction of a directional charge transfer system based on a GO/MXene/UiO-66 (GM/UiO-66) ternary heterojunction for the photocatalytic nitrogen fixation. The internal electric field formed at the heterointerface drives anisotropic migration of photogenerated charges, thereby achieving rapid separation of electron–hole pairs and suppressing interfacial charge recombination. Moreover, the intrinsic defect structure of GO provides key sites for N2 adsorption and activation, while the π-π interactions between GO and UiO-66 further accelerate the movement of photogenerated electrons. In addition, the Schottky junction between UiO-66 and MXene promotes the transfer of holes (h+). The introduction of GO and MXene enhances the absorption of visible light in UiO-66. Under laboratory-simulated solar illumination, the NH3 generation rate of GM/UiO-66 is 1.9 times that of pristine UiO-66 (25.1 vs. 13.5 μmol g−1 h−1). This work offers a novel strategy for designing ternary heterojunction composites that enhance photocatalytic performance by optimizing charge transfer.