(544en) Effect of ?Al2O3 supported Co and Fe Catalysts on Synthesis of Ammonia from CH4 and N2 Using Microwave Plasma

Methane, a major component of natural gas is predominantly used to produce hydrogen (H₂). H₂ along with nitrogen (N₂) from air is combined in a multistage energy intensive Haber-Bosch process to produce ammonia (NH₃). Synthesizing NH₃ at lower temperatures and ambient pressure using CH₄ and N₂ in catalyst assisted microwave reactor system is shown to be an attractive alternative to lower the energy cost. We investigate the role of two metal catalysts in ammonia synthesis from methane (CH₄) and Nitrogen (N₂) under microwave irradiation with and without Argon (Ar) plasma. The catalysts (Co or Fe supported on É£Al₂O₃ ) is synthesized in lab using metal salts and pretreated using microwave irradiation. The microwave reactor is used in two different scenarios. First, a feed of CH₄ and N₂ is run over Co and Fe catalysts separately. Second, 20 % Ar is introduced in the feed to produce plasma. All the reactions are carried at 600 ⁰C and atmospheric pressure. In presence of Co- É£Al₂O₃ , ammonia yield is highest (5500 ppm) with a maximum conversion of CH₄ (82.4%). In this report, we study the interaction of microwaves with the catalysts to explain the better performance of Co over Fe. We also investigate the role of É£Al₂O₃ support in generating plasma in microwave reactor. The fresh and spent catalysts are characterized using state of art tools such as TEM, XRD, SEM and Raman spectroscopy to investigate its surface and bulk properties. Preliminary data shows more carbon species deposition on Co than Fe catalyst. This indicates more hot-spot and local plasma region formation in Co- É£Al2O3which is due to its ability to absorb microwaves better than Fe- É£Al₂O₃.