التفاصيل البيبلوغرافية
| العنوان: |
Novel electrocatalytic membrane for ammonia synthesis |
| المؤلفون: |
Klinsrisuk, Sujitra |
| المساهمون: |
Irvine, John T. S. |
| بيانات النشر: |
University of St Andrews, 2010. |
| سنة النشر: |
2010 |
| المجموعة: |
University of St Andrews |
| مصطلحات موضوعية: |
Ammonia synthesis, Proton conducting oxide membrane, Tape casting, Ion impregnation, BCZYZ, TP223.K6, Ammonia--Synthesis, Electrocatalysis, Slip casting, Oxide ceramics, Fuel cells |
| الوصف: |
Novel ceramic membrane cells of BaCe₀.₅Zr₀.₃Y₀.₁₆Zn₀.₀₄O[subscript(3-δ)] (BCZYZ), a proton-conducting oxide, have been developed for electrocatalytic ammonia synthesis. Unlike the industrial Haber-Bosch process, in this work an attempt to synthesise ammonia at atmospheric pressure has been made. The membrane cell fabricated by tape casting and solution impregnation comprises of a 200 μm-thick BCZYZ electrolyte and impregnated electrode composites. Electrocatalysts for anode and cathode were investigated. For the anode, the co-impregnation of Ni and CeO₂ provided excellent electrode performance including high catalytic activity, sintering stability and compatibility with the BCZYZ electrolyte. The best composition was the mixture of 25 wt% NiO and 10 wt% CeO₂. A symmetrical cell prepared with this electrode composition revealed low polarisation resistances of 1.0 and 0.45 Ωcm² in humidified 5% H₂/Ar at 400 and 500 °C, respectively. For the cathode, 25 wt% of impregnated Fe oxide provided a satisfactory performance in non-humidified N₂ atmosphere. Significant amounts of ammonia were produced from the single cell with Ni-CeO₂ anode and Fe oxide cathode at 400-500 °C under atmospheric pressure. Ammonia formation rate was enhanced by Pd catalyst addition and electrochemical performance was improved by Ru addition. The highest ammonia formation rate of 4 x 10⁻⁹ mols⁻¹cm⁻² was attained using the cell with a Pd-modified Fe cathode at 450 °C. The formation reaction of ammonia typically consumed around 1-2.5 % of total applied current while most of the applied current was employed in H⁺ reduction. The total current efficiency of around 90-100 % could be obtained from the membrane cells. |
| نوع الوثيقة: |
Electronic Thesis or Dissertation |
| اللغة: |
English |
| URL الوصول: |
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.552477 |
| رقم الانضمام: |
edsble.552477 |
| قاعدة البيانات: |
British Library EThOS |