PEMFC에서의 산소 환원 반응을위한 새로운 종류의 전이 금속 및 금속 원자 함유 탄소 촉매의 합성, 특성 분석 및 평가

prohibitionContents Abstract 2 List of Tables 7 List of Figures 8 I. Introduction 14 1.1 Motivation 14 1.2 Polymer electrolyte membrane fuel cells (PEMFCs) 16 1.2.1 Electrochemistry of fuel cell 19 1.2.2 Polarization curve and voltage losses 21 1.2.3 Oxygen reduction reaction (ORR): Reaction Pathway 23 1.3 LT-PEMFC and HT-PEMFC 25 1.3.1 Non-precious based ORR catalysts for LT-PEMFC. 27 1.3.2 Precious Metal based ORR catalyst for LT-PEMFC 30 1.3.3 Precious Metal based ORR catalyst for HT-PEMFC. 33 1.4 Objectives of the Research 35 1.5 Organization of thesis 37 1.6 References 38 II. Physical and electrochemical characterization 47 2.1 Physical characterization 47 2.2 Electrochemical characterization 49 III. Fe-P: A New Class of Electroactive Catalyst for Oxygen Reduction Reaction 52 3.1 Introduction 52 3.2 Experimental section 53 3.3 Results and discussion 53 3.4 Conclusion 63 3.5 References 64 IV. Highly-stable PtPx-based electrocatalysts for oxygen reduction in high temperature-polymer electrolyte membrane fuel cell 68 4.1 Introduction 68 4.2 Experimental Section 70 4.3 Results and Discussion 70 4.4 Conclusions 83 4.5 References 83 V. Preparation of PtPx/Ni2P heterostructures for obtaining efficient Oxygen Reduction Reaction electrocatalyst in Lt-PEMFC 87 5.1 Introduction 87 5.2 Experimental Section 88 5.3 Results and Discussion 88 5.4 Conclusions 99 5.5 References 100DOCTORdCollectio

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Bibliography: p. 99-10

Identification of the environmental hotspots of a recycling process - Case study of a Pt PEMFC catalyst closed-loop recycling system evaluated via life cycle assessment methodology

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Antilithiatic Activity of phlorotannin rich extract of <italic>Sarghassum Wightii</italic> on Calcium Oxalate Urolithiais – <italic>In Vitro</italic> and <italic>In Vivo</italic>Evaluation

ABSTRACTPurpose:Urolithiasis is a common urological disorder responsible for serious human affliction and cost to the society with a high recurrence rate. The aim of the present study was to systematically evaluate the phlorotannin rich extract of Sargassum wightii using suitable in vitro and in vivo models to provide scientific evidence for its antilithiatic activity.Materials and Methods:To explore the effect of Sargassum wightii on calcium oxalate crystallization, in vitro assays like crystal nucleation, aggregation and crystal growth were performed. Calcium oxalate urolithiasis was induced in male Sprague dawley rats using a combination of gentamicin and calculi producing diet (5% ammonium oxalate and rat pellet feed). The biochemical parameters like calcium, oxalate, magnesium, phosphate, sodium and potassium were evaluated in urine, serum and kidney homogenates. Histopathological studies were also done to confirm the biochemical findings.Results:The yield of Sargassum wightii extract was found to be 74.5 gm/kg and confirmed by quantitative analysis. In vitro experiments with Sargassum wightii showed concentration dependent inhibition of calcium oxalate nucleation, aggregation and growth supported by SEM analysis. In the in vivo model, Sargassum wightiireduced both calcium and oxalate supersaturation in urine, serum and deposition in the kidney. The biochemical results were supported by histopathological studies.Conclusion:The findings of the present study suggest that Sargassum wightii has the ability to prevent nucleation, aggregation and growth of calcium oxalate crystals. Sargassum wightii has better preventive effect on calcium oxalate stone formation indicating its strong potential to develop as a therapeutic option to prevent recurrence of urolithiasis.</sec

Urine to highly porous heteroatom-doped carbons for supercapacitor: A value added journey for human waste

Abstract Obtaining functionalized carbonaceous materials, with well-developed pores and doped heteroatoms, from waste precursors using environmentally friendly processes has always been of great interest. Herein, a simple template-free approach is devised to obtain porous and heteroatom-doped carbon, by using the most abundant human waste, “urine”. Removal of inherent mineral salts from the urine carbon (URC) makes it to possess large quantity of pores. Synergetic effect of the heteroatom doping and surface properties of the URC is exploited by carrying out energy storage application for the first time. Suitable heteroatom content and porous structure can enhance the pseudo-capacitance and electric double layer capacitance, eventually generating superior capacitance from the URC. The optimal carbon electrode obtained particularly at 900 °C (URC-900) possesses high BET surface area (1040.5 m2g−1), good conductivity, and efficient heteroatom doping of N, S, and P, illustrating high specific capacitance of 166 Fg−1 at 0.5 Ag−1 for three-electrode system in inorganic electrolyte. Moreover, the URC-900 delivers outstanding cycling stability with only 1.7% capacitance decay over 5,000 cycles at 5 Ag−1. Present work suggests an economical approach based on easily available raw waste material, which can be utilized for large-scale production of new age multi-functional carbon nanomaterials for various energy applications