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Green catalytic synthesis of ammonia using solid oxide electrolysis cells composed of multicomponent materials
- Source :
- Catalysis Today. 374:102-116
- Publication Year :
- 2021
- Publisher :
- Elsevier BV, 2021.
-
Abstract
- This study indicated that joining two different types of solid-state materials, co-doped lanthanum strontium chromium ferrite (LSCrF, La0.33Sr0.67Cr1-xFexO3-δ) perovskite oxide, and gadolinium-doped ceria (GDC, Ce0.9Gd0.1O2-δ) fluorite, yielded series of unique electrocatalytic composites, enabling a green production of ammonia (NH3, (g)) via nitrogen (N2, (g)) and steam (H2O, (g)) reaction at the cathode compartment. An optimized ball milling approach was implemented to produce the cathodic composites with different formulations to respond to the environmental stimuli changes of operational temperature and applied voltage. The solid oxide electrolysis cells (SOECs) were then assembled and used for NH3 production with optimized synthesis and electrochemical measurement variables. As a result, these engineered cathodic catalysts maximized the efficacy of NH3 production due to the formation of oxygen vacancies, high interactivity between catalysts and reactants, and gas channeling through the macro-porous structure. To tune the macro-porous structure of the cathodic composites, the group invented an in-situ templating using a porogen (PMMA, polymethylmethacrylate, (C5O2H8) n) with a controllable size to facilitate gas diffusion and adsorption along with the interfaces of phase boundaries. Electrochemical analyses such as the measurement of impedance demonstrated that the macro-porous structured (LSCrF-GDC) electrode exhibited superior electrocatalytic kinetics. Consequently, the formation rate of NH3 was found to achieve 3.0 × 10−10 mol⋅s-1⋅ cm-2 when the SOEC technology was implemented under an applied voltage of 1.8 V and operating temperature at 600 °C. The mechanistic study of electrochemical performance and interactivity between cathodic catalysts and reactants indicated that an optimized NH3 production pathway was carried out below thermoneutral enthalpy to achieve high efficiency. This goal was achieved through adjustment of the ratio between the enthalpy flow of produced hydrogen and the input of electrical power. The contribution of this study lies in the optimized methodology to enhance interactive electrocatalysis applied for the green synthesis of ammonia.
- Subjects :
- Electrolysis
Materials science
Hydrogen
Oxide
chemistry.chemical_element
02 engineering and technology
General Chemistry
010402 general chemistry
021001 nanoscience & nanotechnology
Electrocatalyst
Electrochemistry
01 natural sciences
Catalysis
0104 chemical sciences
law.invention
chemistry.chemical_compound
Adsorption
chemistry
Chemical engineering
law
0210 nano-technology
Perovskite (structure)
Subjects
Details
- ISSN :
- 09205861
- Volume :
- 374
- Database :
- OpenAIRE
- Journal :
- Catalysis Today
- Accession number :
- edsair.doi...........b381b36ad55f38cff9db2dd5fdad4ea5