Exploring the Role of Nanoscale Catalysts Synthesized via Spray Flame Aerosol Reactor for Single Step CO2 Hydrogenation to Dimethyl Ether

ONOCHIE OKONKWO, Komal Tripathi, Sonal Asthana, Yiming Xi, Sujit Modi, Kamal Kishore Pant, Pratim Biswas, University of Miami

     Abstract Number: 349
     Working Group: Nanoparticles and Materials Synthesis

Abstract
The direct conversion of CO₂ to dimethyl ether (DME) is regarded as an innovative approach for recycling CO₂. Compared to the conventional two-step process which involves methanol synthesis and subsequent methanol dehydration to DME, the direct DME synthesis overcomes the thermodynamic limitation of methanol synthesis and results in process intensification because two reactors are integrated into a single reactor. Consequently, the direct DME synthesis process lowers capital and operating costs, while offering a sustainable route for utilizing carbon dioxide [1].

A highly selective Cu/ZnO/MgO admixed with γ-Al₂O₃ catalyst for direct DME synthesis from H₂/CO/CO₂ mixture has been produced by precipitation [2]. Also, Cu/ZnO/ZrO₂ admixed with ZSM-5 catalyst for CO₂ hydrogenation to DME has been produced by precipitation [3]. The precipitation process involves several steps and requires long times for catalysts synthesis. To overcome the limitations of the precipitation process, the flame synthesis route is used to obtain the same catalysts. Flame synthesis is an easily scalable, continuous, single step synthesis method for catalyst manufacture [4].
In this work, Cu/ZnO/MgO and Cu/ZnO/ZrO₂ catalyst is synthesized via flame synthesis, characterised, and explored for DME synthesis. The flame synthesized catalyst activity, selectivity, and stability for DME synthesis is compared to that prepared by co-precipitation to demonstrate its superior performance. The characterization results reveal the structural characteristics which provides insight to describe the performance of the flame synthesized catalyst. Altogether, flame synthesis is used to elucidate the governing aspects for designing high performance catalysts for CO₂ hydrogenation.

[1] T. Komal, et al., Sustainable Energy & Fuels 5:10 (2021) 2781-2801.
[2] A. Sonal, et al., Energy & Fuels 36:5 (2022) 2673-2687.
[3] S. Rajan, et al., Fuel 318 (2022): 123641.
[4] S. Li et al., Progress in Energy and Combustion Science, 55 (2016) 1-59.