Microwave-assisted ammonia synthesis over Ru/MgO catalysts at ambient pressure

In this work a fixed frequency (2.45 GHz) microwave (MW) was used to synthesis ammonia over Ru/MgO catalysts under ambient atmospheric pressure at 320 ?C. The loading of Ru catalyst over MgO was varied at 4 wt% and 10 wt%. The metal support interaction was found to play an important role not only catalytically but also altering the microwave-catalyst interaction affecting the ammonia formation rate. The higher metal loading (10 wt%) produced the most activity, stability, and energy efficiency. It was found the Ru was better dispersed at higher loading which decreased the sintering of the catalyst due to lower microwave energy needed to maintain the reaction temperature. Additional effects from the microwave can include enhanced electron movement and/ or electric fields formed between the metal sites of the catalyst. The microwave reactor offers a quick on/off catalyst recovery, within 11 min, compared to thermal convectional Haber Bosch (HB) technology.

Automated summary

In this study, microwave synthesis of ammonia over Ru/MgO catalysts was conducted at 320℃ under ambient pressure with different Ru loading levels. Higher Ru loading showed better dispersion, leading to decreased sintering and enhanced activity and stability. The microwave reactor also offered faster catalyst recovery compared to traditional thermal convectional Haber Bosch (HB) technology.