CC3 porous organic cage crystals and membranes for the non-thermal plasma catalytic ammonia synthesis

Ammonia is considered a basic building block for fertilizers. Also, it is an economically efficient and technologically suitable solution for energy storage and transportation. Non-thermal plasma-driven catalysis powered by renewable energy is considered as a green alternative to the conventional Haber-Bosch process for ammonia synthesis. The main challenge in this electron-mediated route is the low ammonia synthesis production, given the plasma-induced decomposition of the freshly generated ammonia during the reaction. Herein we report the plasma-assisted ammonia synthesis in a dielectric barrier discharge reactor packed with CC3 crystals, a prototypical porous organic cage, and a molecular-sieve membrane fabricated from the same CC3 material. The CC3 crystals delivered the highest ammonia synthesis rate (0.06 & mu;mol min-1 m-2) compared to other microporous catalysts such as zeolite (SAPO-34) and metal-organic frameworks (ZIF-8, ZIF-67) (below 0.02 & mu;mol min-1 m-2). The CC3 porous cage with well-defined octahedral crystal geometry provides partial protection while the CC3 membrane offers both adsorption and separation effects for the freshly formed ammonia from its in-situ decomposition, securing an excellent ammonia synthesis rate of 20.3 & mu;mol min-1 m- 2. The findings from this work unfolds novel insights into rational designs of advanced porous catalyst and membrane for plasma-driven catalytic ammonia synthesis in a sustainable and efficient way.

Automated summary

This study presents a plasma-assisted ammonia synthesis method using a dielectric barrier discharge reactor packed with CC3 crystals and a molecular-sieve membrane made from the same material. The CC3 crystals demonstrated the highest ammonia synthesis rate, while the CC3 membrane provided both protection and separation effects, resulting in an excellent ammonia synthesis rate.