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Efficient Non-PGM Electrocatalysts for Hydrazine Electrooxidation in Alkaline Media

Title
Efficient Non-PGM Electrocatalysts for Hydrazine Electrooxidation in Alkaline Media
Translated Title
효율적인 하이드라진 전기 분해반응을 위한 비귀금속 기반의 코어쉘 타입 촉매.
Authors
Son, Min Ho
DGIST Authors
Son, Min Ho; Sangaraju ShanmugamSon, Byung Rak
Advisor(s)
상가라쥬샨무감
Co-Advisor(s)
Son, Byung Rak
Issue Date
2020
Available Date
2020-08-06
Degree Date
2020/08
Type
Thesis
Description
"Hydrazine electrooxidation", "Direct Hydrazine Fuel Cell", "Non-PGM electro catalysts", "Core-shell structure"
Abstract
Hydrazine electrooxidation (HzOR) is considered one of the hydrogen production methodologies. For enhancing HzOR activity and reducing the use of PGM metals, we synthesized core-shell structured catalysts, varying by different transition metal species and pyrolysis temperature. As a result, Ni@NC-600, Fe@NC-600 and Co@NC-500, 600, 700, 800 and 900 are synthesized and tested for HzOR. Co@NC shows quite low onset potential, each trend of initial activity and durability is related to the graphitization of carbon shell and the ratio between hexgonal close packed (HCP) Co and face centered cubic (FCC) Co. The initial activity depends on the number of active sites, that is more blocked with the presence of highly graphitized carbon shell. However, Co@NC-900 didn’t show the best durability because too much graphitized carbon which block lots of active sites. In conclusion, Co@NC-800 is the most optimized catalyst for HzOR. Co@NC-800 shows Ponset at the potential of -0.134 V, which is much lower than Ponset of 40% Pt/C. However, the activity of 40% Pt/C is more higher than Co@NC-800 over the potential of 0.1 V, which could be attributed to the difference of the surface area of two catalysts.
Table Of Contents
Ⅰ. Introduction 1 1.1 Motivation 1 1.2 Theoretical background 2 1.2.1 Hydrazine Electrooxidation (HzOR) 2 1.2.2 HzOR fundamentals 3 1.2.3 Comparison of HzOR catalysts in alkaline 4 1.2.4 Direct Hydrazine Fuel Cell (DHFC) 6 1.2.5 Core shell catalyst – From PB to NC 7 1.3 Objectives 7 II. Experimental 9 2.1 Preparation of electrocatalysts 9 2.1.1 Chemicals 9 2.1.2 Synthetic approach 9 2.2 Characterization 11 2.2.1 X-ray diffraction (XRD) 11 2.2.2 Transmission electron microscopy (TEM) 11 2.2.3 X-ray photoelectron spectroscopic (XPS) 12 2.2.4 Electrochemical measurements 12 III. Results and discussion 13 3.1 M@NCs 13 3.1.1 Characterization 13 3.1.2 Morphology analysis 19 3.1.3 Electrochemical studies 22 3.2 Single phase metallic cobalt 30 3.2.1 HzOR activity 30 IV. Conclusions 31 References 32 국 문 요 약 문 38 Acknowledgement 39
URI
http://dgist.dcollection.net/common/orgView/200000332783
http://hdl.handle.net/20.500.11750/12160
DOI
https://doi.org/10.22677/thesis.200000332783
Degree
Master
Department
Department of Energy Science and Engineering
University
DGIST
Related Researcher
  • Author Shanmugam, Sangaraju Advanced Energy Materials Laboratory
  • Research Interests Electrocatalysts for fuel cells; water splitting; metal-air batteries; Polymer electrolyte membranes for fuel cells; flow batteries; Hydrogen generation and utilization
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Collection:
Department of Energy Science and EngineeringThesesMaster


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