Interfacial Zn─O─Ti Sites for Efficient Photocatalytic Urea Synthesis from CO₂ and N₂

Urea photosynthesis from CO₂ and N₂ has profound environmental and energy implications. However, the simultaneous activation of CO₂ and N₂, along with the promotion of C─N bond formation, remains a major challenge. Herein, the asymmetric interfacial sites (Zn─O─Ti) were engineered by building oxygen atom bridges between ZIF-8 and MIL-125 to enable efficient photocatalytic urea synthesis. The optimized Zn─O─Ti interface structure achieves a urea yield of 130 µmol g^-1 h^-1 in pure water and an apparent quantum yield of 5.52% at 350 nm, outperforming most materials reported for urea photosynthesis. Mechanistic studies reveal that Zn sites catalyze the conversion of CO₂ to *CO species, while Ti sites adsorb and activate N₂ to generate *NH-NH species. The asymmetric interfacial sites lower the energy barrier for the coupling of *CO and *NH-NH to form *CONH₂ intermediates, thereby promoting urea photosynthesis. This work provides significant insights into designing interfacial asymmetric sites to facilitate photosynthetic organic chemicals for upgrading the nitrogen cycle.