https://ir.lib.ncu.edu.tw/handle/987654321/342 Search the Channel s https://ir.lib.ncu.edu.tw/simple-search https://ir.lib.ncu.edu.tw/handle/987654321/50027 title: Uniform dispersion of Pd nanoparticles on carbon nanostructures using a supercritical fluid deposition technique and their catalytic performance towards hydrogen spillover abstract: With the aid of supercritical carbon dioxide (scCO(2), which has gas-like diffusivity, extremely low viscosity, and near-zero surface tension, highly dispersed Pd nanoparticles (NPs) can be directly synthesized on carbon nanotubes (CNTs). Due to the excellent wettability between scCO(2) and the carbon surface, the deposited Pd NPs are uniformly distributed and tightly anchored on CNTs, which do not require pretreatment. The decoration density of NPs on carbon can be easily regulated by adjusting the Pd(hfa)(2) precursor to CNT ratio, with the particle size of Pd remaining almost constant (no significant crystal growth or aggregation occur). The prepared Pd NPs on CNTs show excellent activity toward hydrogen spillover as compared to those fabricated using conventional processes. With the superior utilization of NPs, a smaller amount of Pd is required, reducing both costs and environmental impact. The proposed scCO(2)-assisted protocol for constructing NP/carbon nanostructures is effective, versatile, and potentially scalable, making it useful for further exploitation in a variety of applications. <br> https://ir.lib.ncu.edu.tw/handle/987654321/50026 title: The effect of oxygen containing species on the catalytic activity of ethanol oxidation for PtRuSn/C catalysts abstract: The effect of oxygen containing species (OCS) on the electrochemical activities of carbon supported PtRu, PtSn, and PtRuSn electrocatalysts has been investigated. The catalysts are prepared by the precipitation-deposition method and applied for the ethanol oxidation reaction (EOR). The oxidation treatment is applied to generate the OCS for these catalysts in order to realize their influences on the mechanism of EOR. The distinct effects of OCS on EOR performance are observed. RuO(2) enhances the activity of EOR only in high potential region due to the promotion of CO oxidation, while Pt(3)Sn, SnO or SnO(2) can promote both dissociative adsorption of ethanol on Pt surface and the CO oxidation reaction, thus the EOR activity increases in whole potential region. However, for the oxidized ternary PtRuSn catalysts where RuO(2) and SnO(2) coexist and cover the Pt active sites, the EOR activity deteriorates. Herein, the best catalyst for EOR is the as-reduced PtRuSn/C among all samples owing to the surface OCS (SnO) and an appropriate Ru/Sn surface ratio. For the oxidized sample. PtRu/C displays high EOR activity. Models for the mechanism of EOR on the PtRuSn/C catalysts are also proposed on the basis of the results presented here. (C) 2010 Elsevier Ltd. All rights reserved. <br> https://ir.lib.ncu.edu.tw/handle/987654321/50025 title: Synergistic effect of Co alloying and surface oxidation on oxygen reduction reaction performance for the Pd electrocatalysts abstract: The synergistic effect of Co alloying and oxidation treatment induced progressive enhancement on oxygen reduction reaction (ORR) activities of Pd/C catalysts is studied. Based on the XPS characterization, a new term, degree of surface oxidation (DSO), is proposed to illustrate their relationship between ORR activity and surface oxidation extent. TPR characterization also provides the evolution of surface species within the topmost region. It can be obviously found the optimal temperature for the promotion of ORR activity on various oxidized samples is 520 K. On the other hand, various heat treatment atmospheres (H(2) and CO) are applied on Pd Co system without changing their particle size. It is clearly evident that the oxidized catalysts can exhibit the superior performance relative to that of the non-oxidized ones, confirming the improved ORR activity is solely ascribed to the formation of surface PdO species with 100% DSO value rather than large particle size effect. Moreover, an explainable model is demonstrated to illustrate the promotional effect of ORR performance on the oxidized PdCo/C catalysts. Copyright (C) 2010, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. <br> https://ir.lib.ncu.edu.tw/handle/987654321/50024 title: Surface Condition Manipulation and Oxygen Reduction Enhancement of PtAu/C Catalysts Synergistically Modified by CeO(2) Addition and N(2) Treatment abstract: In this study, the electrochemical activity of Pt(50)Au(50)/C toward oxygen reduction reaction has been promoted by the manipulation of their surface condition through CeO(2) addition and N(2) heat treatment synergistically. Pt(50)Au(50)/C with CeO(2) additions (PtAuCe) were prepared by the DP process and then further treated at 520-620 K under N(2). The surface segregation profile of the PtAuCe alloys and surface-activity correlation has been elucidated systematically by use of the surface analysis and electrochemical characterization. It is observed that the inherent surface segregation of Au of Pt-Au systems at high temperatures based on the thermodynamic models has been changed due to the CeO(2) modification, and accordingly in the PtAuCe catalysts, CeO(2)-induced Pt surface segregation and surface reconstruction takes place. As a result, the variations in surface compositions affect the ORR activity of the Pt-Au catalysts, and the enhancement of Pt or Au surface composition causes the promotion or deterioration in ORR activity for various heat-treated catalysts, respectively <br>