Facet Engineering and Fe─N─Co Bridged Heterojunction Enable Fe ₃ O ₄ @C@ZIF67 as High‐Performance Photocatalyst for Ammonia Synthesis

Abstract

Abstract Ammonia synthesis is vital for global fertilizer production but traditionally relies on the energy‐intensive Haber–Bosch process, a major contributor to CO 2 emissions. Photocatalytic nitrogen reduction reaction (PNRR) offers a sustainable alternative by harnessing solar energy under ambient conditions. However, challenges such as low nitrogen adsorption, poor conductivity, and high electron‐hole recombination of the photocatalysts limit their efficiency. This study introduces an Fe 3 O 4 @C@ZIF67 core‐shell photocatalyst featuring an Fe─N─Co bridged Z‐scheme heterojunction. This design incorporates carbon‐coated Fe 3 O 4 in ZIF67‐D (ZIF67‐dodecahedron) with exposed (211) crystalline facets to enhance nitrogen adsorption. Fe─N 4 and Co─N 4 active sites improve catalytic activity, while the carbon layer enhances conductivity and facilitates oxygen vacancy formation. The Fe─N─Co bridged heterojunction further promotes charge separation and transfer. Therefore, the Fe 3 O 4 @C@ZIF67 composite achieves an outstanding ammonia yield of 33.2 mmol L −1 g −1 h −1 (outperforming other systems) with high selectivity and minimal by‐products. This work provides valuable insights into the design of high‐performance photocatalysts by integrating the advantages of metal–organic frameworks, core‐shell architectures, and interfacial engineering, marking a significant step forward in sustainable ammonia synthesis.