Enhancing photocatalytic N2 fixation efficiency through the construction of optimized hollow ZnO/Cu Mott-Schottky heterojunction microreactors

The application of photocatalysis for the production of high-purity and high-energy-density green ammonia holds substantial promise. However, the restricted light absorption efficiency and high recombination rate of electron-hole pairs present significant obstacles to its practical deployment. In this study, we enhanced the photocatalytic efficiency of N 2 fixation by engineering a Mott-Schottky heterojunction and incorporating hollow microreactors. We synthesized Hollow-ZnO (H-ZnO) using ZIF-8 as a precursor and subsequently deposited Cu nanoparticles onto the H-ZnO to create the H-ZnO/Cu photocatalyst. The hollow structure not only bolstered the catalyst’s light scattering and absorption capabilities but also reduced the path length for photogenerated electron transitions, thereby improving the efficiency of electron transport and effectively inhibiting electron-hole pair recombination. Under Xe lamp irradiation, the H-ZnO/Cu-3 photocatalyst achieved a superior NH 4 + yield of 68.1 μmol g −1 h −1 without the addition of any sacrificial reagents, representing a 7.5-fold enhancement over pure ZnO. This research offers a novel strategy for designing metal oxide photocatalysts derived from MOFs and developing cost-effective photocatalytic systems.