Photocatalytic nitrogen fixation has attracted much attention due to the fact that it is a way of using solar energy to achieve clean and sustainable conversion of nitrogen to ammonia under mild conditions. In this paper, different proportions of Zn-doped Co₃O₄ nanopolyhedrons were synthesized using bimetallic ZIFs containing Co²⁺ and Zn²⁺ as precursors for the construction of photocatalytic nitrogen fixation semiconductor materials for the first time. The synthesized Co₃O₄ nano-polyhedron still retains the rhombic dodecahedron shape of ZIF-67 and exhibits a large specific surface area. Moreover, Zn doping results in abundant oxygen vacancies on the surface of Co₃O₄ polyhedron. These oxygen vacancies not only provide active sites for nitrogen adsorption and activation, but also enhance the separation ability of photocarriers, which can significantly improve the efficiency of photocatalytic nitrogen fixation of the material. When Zn–Co₃O₄-30 is utilized as the catalyst for photocatalytic nitrogen fixation, the nitrogen fixation rate is 96.8 μmol g⁻¹ h⁻¹, which is much higher than that of pure-Co₃O₄. In this study, heteroatom-doped Co₃O₄ polyhedron with rich oxygen vacancy was synthesized by low-temperature oxidation method, which provides a new idea for the design and synthesis of skeleton-based photocatalytic nitrogen fixation materials.

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