Strengthening of fluidized catalysts for green ammonia production using DBD plasma assistance

The Haber-Bosch technique, which is the typical process used to produce ammonia, is very effective but requires strict reaction conditions, which leads to high energy consumption and carbon dioxide emissions. This work suggested a technique for high-efficiency ammonia synthesis that coupled water vapor with fluidized catalysts and non-thermal plasma as a green feedstock. The catalytic NH3 production rates and energy efficiency (EE) of the several supported catalysts produced for this investigation were as follows in order: $\mathrm{Co}-\mathrm{Ni} / \mathrm{MgO}\gt \mathrm{Co} / \mathrm{MgO}\gt \mathrm{Ni} / \mathrm{MgO}\gt \mathrm{Co}-\mathrm{Ni}_{2} / \mathrm{Al}_{2} \mathrm{O}_{3}\gt \mathrm{MgO}\gt \mathrm{Al}_{2} \mathrm{O}_{3}$. The findings indicate that NH
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production rates are much greater for bimetallic $\mathrm{Co}-\mathrm{Ni}$ supported catalysts on the MgO carrier compared to single-component metal-supported catalysts and the absence of catalysts. By applying solid characterization methods, we were able to verify that the catalyst carrier’s alkalinity and acidity on the surface are critical factors influencing the effectiveness of nitrogen fixation for ammonia synthesis. These results indicated that the NH3 formation rate peaked with an increase in specific energy input (SEI). However, further increments in SEI resulted in a decrease in ammonia production. The highest NH
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formation rate was reached $12.07 \mathrm{~mol} \mathrm{~g}^{-1} \mathrm{~h}^{-1}$ (SEI of $2.15 \mathrm{~kJ} \mathrm{~L}^{-1}$, EE of $6.57 \mathrm{mg} \mathrm{kW}^{-1} \mathrm{~h}^{-1}$). Notably, good fluidization behavior was facilitated by the plasma created between catalyst particles in the fluidized condition. When compared to fixed-bed conditions, the nitrogen fixation efficiency was significantly improved due to the fluidized bed’s increased contact area between the fluidized catalysts and plasma reactants. This study’s use of plasma technology provided the energy required for nitrogen triple-bond cleavage. It offers a novel platform for sustainable ammonia synthesis and significantly increases ammonia yield.