Multi-heterointerfaces for selective and efficient urea production

A multiple heterogeneous interface with unique incomplete charge transfer is constructed by growing graphdiyne in situ on cobalt-nickel mixed oxides surface, effectively promoting high-performance urea production at room temperature and pressure. A major impediment to industrial urea synthesis is the lack of catalysts with high selectivity and activity, which inhibits the efficient industrial production of urea. Here, we report a new catalyst system suitable for the highly selective synthesis of industrial urea by in situ growth of graphdiyne on the surface of cobalt-nickel mixed oxides. Such a catalyst is a multi-heterojunction interfacial structure resulting in the obvious incomplete charge-transfer phenomenon between a graphdiyne and metal oxide interface and multiple intermolecular interactions. These intrinsic characteristics are the origin of the high performance of the catalyst. Studies on the mechanism reveal that the catalyst could effectively optimize the adsorption/desorption capacities of the intermediate and promote direct C-N coupling by significantly suppressing by-product reactions toward the formation of H-2, CO, N-2 and NH3. The catalyst can selectively synthesize urea directly from nitrite and carbon dioxide in water at room temperature and pressure, and exhibits a record-high Faradaic efficiency of 64.3%, nitrogen selectivity (N-urea-selectivity) of 86.0%, carbon selectivity (C-urea-selectivity) of similar to 100%, as well as urea yield rates of 913.2 mu g h(-1) mg(cat)(-1) and remarkable long-term stability.

Automated summary

A multiple heterogeneous interface with unique incomplete charge transfer was constructed by growing graphdiyne on cobalt-nickel mixed oxides surface, enabling high-performance urea production at room temperature and pressure. The catalyst system exhibits outstanding performance in selectively synthesizing urea directly from nitrite and carbon dioxide, with a record-high Faradaic efficiency, nitrogen and carbon selectivity, as well as remarkable long-term stability.