Facet Engineering and Fe─N─Co Bridged Heterojunction Enable FeO@C@ZIF67 as High-Performance Photocatalyst for Ammonia Synthesis.

Ammonia synthesis is vital for global fertilizer production but traditionally relies on the energy-intensive Haber-Bosch process, a major contributor to CO 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 FeO@C@ZIF67 core-shell photocatalyst featuring an Fe─N─Co bridged Z-scheme heterojunction. This design incorporates carbon-coated FeO in ZIF67-D (ZIF67-dodecahedron) with exposed (211) crystalline facets to enhance nitrogen adsorption. Fe─N and Co─N 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 FeO@C@ZIF67 composite achieves an outstanding ammonia yield of 33.2 mmol L g h (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.