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Improving Quality Of Cvd Graphene Grown On The Copper Foil By Physical Polishing Electropolishing And Thermal Annealing Pretreatment Processes, Methawut Sirisom
Improving Quality Of Cvd Graphene Grown On The Copper Foil By Physical Polishing Electropolishing And Thermal Annealing Pretreatment Processes, Methawut Sirisom
Chulalongkorn University Theses and Dissertations (Chula ETD)
This study optimized the pretreatment processes (physical polishing (PP), electropolishing (EP), and thermal annealing) for high-quality graphene growth on thin copper (Cu) foils. PP using Brasso solvent was applied to smoothen the substrate surface, followed by EP with H3PO4 to reduce rolling lines and surface contamination. The EP process involved different H3PO4 concentrations (30-60%) and etching times (60-120 seconds). After thermal annealing at 860-940 ºC, graphene growth was performed using direct-liquid-injection chemical-vapor deposition with cyclohexane (C6H12) as the carbon precursor and nitrogen as the carrier gas. The optimized conditions involved PP and EP with 45% H3PO4 concentration and 90 seconds …
High-Pressure Study Of Hybrid Organic-Inorganic Perovskites And Double Perovskites, Ardimas -
High-Pressure Study Of Hybrid Organic-Inorganic Perovskites And Double Perovskites, Ardimas -
Chulalongkorn University Theses and Dissertations (Chula ETD)
Hybrid and double perovskite have been of great attraction for optoelectronic devices. However, exploring a feasible method to enhance their optical abilities remains a considerable challenge. Here, the researcher reports the pressure-induced phase transition as an effective way to modify optoelectronic properties. The researcher successfully synthesized the hybrid perovskite (MAPbI3) and the double perovskite (Cs2TiBr6) by the inverse temperature crystallization (ITC) and solution method, respectively. the researcher studied the pressure dependence phase transition and photoluminescence (PL) by placing the sample into diamond anvil cells (DACs) through Raman spectroscopy. The first principles method was used to support the idea. The researcher …
Nanoporous Cu-Based Catalytic Electrodes For Electrochemical Conversion Of Carbon Dioxide, Jidsucha Darayen
Nanoporous Cu-Based Catalytic Electrodes For Electrochemical Conversion Of Carbon Dioxide, Jidsucha Darayen
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research investigates the strategies to enhance copper electrodes for carbon dioxides reduction reactions (CO2RR) for generation of valuable chemical products, including methanol and acetaldehyde. Through modifications of physical characteristics of electroplated copper electrodes, particularly introduction of porosity, and chemical composition, namely formation of copper oxides, the key performance parameters for CO2RR including selectivity, Faradaic efficiency, and energy efficiency are examined. Furthermore, the relationships between copper electrodes’ plating variables (current density, deposition time, and bath solution), porosity and compositions, and corresponding CO2RR performances are constructed. The study has demonstrated that the ratio of CuSO4 and H2SO4 of bath solution, current …
A New Spinel High-Entropy Oxides Nanoparticles (Feconimnzn)3o4 As Anode Materials For Lithium-Ion Batteries, Maha Nur Aida
A New Spinel High-Entropy Oxides Nanoparticles (Feconimnzn)3o4 As Anode Materials For Lithium-Ion Batteries, Maha Nur Aida
Chulalongkorn University Theses and Dissertations (Chula ETD)
A novel (FeCoNiMnZn)3O4 HEO as an anode in lithium-ion batteries (LIBs) was developed for the first time. High-entropy oxide (HEO) of (FeCoNiMnZn)3O4 was synthesized using a hydrothermal technique to control size and crystallinity. We also synthesized oxides of each element (Fe, Co, Ni, Mn, Zn) from HEO composition under similar condition for comparison. The samples were then analyzed using XRD, SEM, TEM, EDS elemental mapping, surface area analysis, ICP-OES, and XPS. Cyclic voltammetry, galvanostatic charge-discharge, electrochemical impedance spectroscopy, and associated coulombic efficiencies were also used to study the electrochemical performance of (FeCoNiMnZn)3O4. Three samples with different preparation conditions, HEO-3, HEO-6, …
Biopolymer Nanocomposites For Food And Healthcare Applications, Tatiya Siripongpreda
Biopolymer Nanocomposites For Food And Healthcare Applications, Tatiya Siripongpreda
Chulalongkorn University Theses and Dissertations (Chula ETD)
This dissertation focuses on development of biopolymers by integrating nanomaterials to improve the properties of pristine polymers for enhancing the performances of chemical sensors and laser desorption/ionization mass spectroscopy (LDI-MS) applied for food quality control health monitoring and biomedical applications. The dissertation is divided into 4 parts: the first part, polylactic acid and cellulose were used for dual detection platform of biogenic amines for food spoilage indication. Highly porous PLA film is fabricated by adding nanosized calcium carbonate resulted in high sensing element entrapment. On another side of platform, pristine cellulose is modified with graphene oxide and exploited a substrate …