https://ir.lib.ncu.edu.tw/handle/987654321/186 Search the Channel s https://ir.lib.ncu.edu.tw/simple-search https://ir.lib.ncu.edu.tw/handle/987654321/110363 title: TiFe 基合金在不純氫氣的吸氫性能;TiFe 基合金在不純氫氣的吸氫性能 abstract: 本研究採用非計量比Ti含量提升與Cr摻雜之協同設計方法，製備Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅與Ti₁.₃Fe₀.₉Cr₀.₁兩種TiFe基儲氫合金，分別探討成分設計對微結構特徵、儲氫熱力學性質及抗雜質毒化能力之影響。微結構分析結果顯示，Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅及Ti₁.₃Fe₀.₉Cr₀.₁試片因Cr的固溶置換使主相晶格常數由2.9760 Å(純TiFe相)分別膨脹至2.9829 Å及2.9935 Å，此晶胞膨脹效應有助於擴增氫原子進入晶格的間隙空間；此外，兩者試片皆含微量Ti₂Fe二次相(約1%)，以上兩種結構有利於提升TiFe基室溫活化能力。 雜質氣體循環老化測試結果顯示，兩種合金在200 ppm 的N₂、O₂、CO₂及CO雜質氣體環境下的毒化強度排序一致為CO ≥ CO₂ > O₂ > N₂。其中對於Ti₁.₃Fe₀.₉Cr₀.₁合金而言，N₂對儲氫性能影響最為輕微，30次循環後衰退率僅約14%、；O₂環境下的衰退率49.6%、，顯著優於Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅合金的62.0%、，顯示Cr元素具有保護TiFe主相的效應；CO₂與CO則分別造成約85%與95%的嚴重性能衰退，結果證實Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅及Ti₁.₃Fe₀.₉Cr₀.₁兩種合金均難以抵抗其雜質對合金的毒化效應。Ti1.3Fe0.9Cr0.1試片在CO₂與CO雜質氣體老化測試後的XRD繞射圖譜經由Rietveld精修分析，合金內部殘留大量β-TiFeHₓ與γ-TiFeH₂氫化相，其根源在於雜質分子在氫化相變化過程中包覆合金表面，阻斷脫氫路徑、。最後，本研究成果與國際間比較、，非計量比Ti含量提升與Cr摻雜的協同方法些微改善TiFe合金的活化性能與抗O₂及CO2之毒化能力。;In this study， a synergistic design approach combining off-stoichiometric Ti enrichment and Cr doping was adopted to fabricate two TiFe-based hydrogen storage alloys， Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅ and Ti₁.₃Fe₀.₉Cr₀.₁， with the aim of systematically investigating the effects of compositional design on microstructural characteristics， hydrogenation thermodynamic properties， and resistance to impurity poisoning. Microstructural analysis revealed that due to Cr substitution， the lattice parameters for the primary phase of the Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅ and Ti₁.₃Fe₀.₉Cr₀.₁ samples expanded from 2.9760 Å (pure TiFe phase) to 2.9829 Å and 2.9935 Å， respectively. This unit cell expansion effect facilitates the enlargement of interstitial sites for hydrogen atoms to enter the lattice. Furthermore， both samples contained a trace amount of a secondary Ti₂Fe phase (approximately 1%). Both of these structural characteristics are beneficial for enhancing the activation capability of the TiFe-based alloys at room-temperatures. Cyclic hydrogenation tests under 200 ppm impurity gas demonstrated that both alloys exhibited a similar poisoning severity ranking of CO ≥ CO₂ > O₂ > N₂. For the Ti₁.₃Fe₀.₉Cr₀.₁ alloy， N₂ showed the mildest impact on hydrogen storage performance， with a capacity degradation rate of only about 14% after 30 cycles. Under O₂ exposure， the hydrogenation degradation rate was 49.6%， which is significantly better than that of the Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅ alloy (62.0%)， indicating a protective effect of the Cr element on the TiFe matrix. CO₂ and CO， however， caused severe hydrogenation degradation of approximately 85% and 95%， respectively， indicating that both the Ti₁.₀₅Fe₀.₉₅Cr₀.₀₅ and Ti₁.₃Fe₀.₉Cr₀.₁ alloys were unable to resist the poisoning effects of these impurities. Rietveld refinement analysis of the XRD patterns for the Ti₁.₃Fe₀.₉Cr₀.₁ sample after CO₂ and CO impurity gas cyclic tests revealed that substantial amounts of residual β-TiFeHₓ and γ-TiFeH₂ hydride phases were retained within the alloy. The main reason of this is that impurity molecules encapsulated the alloy surface during the phase transformation of metal hydrides， thereby blocking the dehydrogenation pathways. Finally， compared with international studies， the results of this research demonstrate that the synergistic approach of off-stoichiometric Ti enrichment and Cr doping slightly improves the activation performance and the resistance to O₂ and CO₂ poisoning of TiFe-based alloys. Keywords: TiFe-based hydrogen storage alloy， non-stoichiometric， Chromium doping， Impurity poisoning， Cyclic degradation， Activation behavior <br> https://ir.lib.ncu.edu.tw/handle/987654321/110360 title: 利用超薄硒中介層調控 Au/MoS₂ 接面之傳導特性;Effect of an Ultrathin Se Interlayer on the electrical transport properties of Au/MoS₂ junctions abstract: 二硫化鉬（MoS₂）具有原子級厚度、半導體能隙與良好的閘極調控能力，被視為具潛力之二維半導體材料。然而，在實際元件中，金屬與 MoS₂ 接觸界面常受到費米能階釘紮、界面態與蕭特基能障影響，使載子注入效率受到限制，進而影響元件之導通電流與輸出特性。本研究於 Au/MoS₂ 接觸界面中導入超薄硒（Se）中介層，製作 Au/Se/MoS₂ 接觸結構，並探討 Se 中介層對 MoS₂ 材料特性、接觸能階排列與電晶體電性傳輸之影響。 首先，利用 Raman 與 PL 光譜分析 Se 中介層與 Au 電極沉積後 MoS₂ 之晶格振動與光學特性變化，以觀察製程後可能產生之應力、電荷轉移與界面交互作用。接著，本研究製作背向閘極 MoS₂ 電晶體，並透過轉移特性與輸出特性分析 Se 中介層對 Au/MoS₂ 接面載子傳輸行為之影響。電性結果顯示，隨著 Se 中介層厚度增加，元件導通電流逐漸下降，且輸出特性於低偏壓區呈現較明顯之非線性，顯示 Se 中介層可能使接觸端載子注入受到更強限制。為進一步定量分析接觸能障變化，以變溫電性量測與 Arrhenius 分析萃取蕭特基能障。結果顯示，元件之平帶蕭特基能障呈現隨 Se 厚度增加而上升之趨勢。Se 中介層會提高 Au/MoS₂ 接面之電子注入障礙，對應電性中觀察到之電流下降與接觸限制增強。Au–MoS₂ / Au/Se–MoS₂ 非對稱接觸元件中，2 nm Se 非對稱元件之理想因子約為 1.31，較 1 nm Se 元件之 2.22 更接近理想二極體行為，且與其較高整流比相互呼應。此結果說明適當厚度之 Se 中介層可形成較明顯且較穩定的非對稱接觸能障，使元件呈現較佳之整流特性與二極體傳輸行為。;Molybdenum disulfide (MoS₂) is a promising two-dimensional semiconductor; however， its device performance is often limited by metal/MoS₂ contact barriers and Fermi-level pinning. In this study， an ultrathin selenium (Se) interlayer was inserted into the Au/MoS₂ contact interface to form Au/Se/MoS₂ junctions， and its influence on energy-level alignment， Schottky barrier height， and electrical transport behavior was investigated. Raman and photoluminescence measurements indicate that Au deposition and Se insertion modify the lattice vibration and optical response of MoS₂， suggesting interfacial interactions and local changes in the MoS₂ environment. UPS analysis shows that the Se interlayer shifts the Fermi level farther from the MoS₂ conduction band edge， with (EC-EF) increasing from approximately 0.09 eV for Au–MoS₂ to 0.20 eV for Au/Se–MoS₂， indicating an increased electron injection barrier. Back-gated MoS₂ transistors with Se interlayers maintained n-type behavior， but their on-current decreased and output characteristics became more nonlinear as the Se thickness increased. Temperature-dependent measurements further confirmed that the flat-band Schottky barrier height increased from 97 meV for the Au–MoS₂ device to 145， 242， and 334 meV for 1， 2， and 3 nm Se interlayers， respectively. Asymmetric Au–MoS₂/Au/Se–MoS₂ devices exhibited rectifying behavior， with maximum rectification ratios of approximately 480 and 630 for 1 and 2 nm Se interlayers. These results demonstrate that ultrathin Se acts as a barrier-modulating interlayer and can effectively tune the electrical transport properties and rectifying behavior of Au/MoS₂ junctions. <br> https://ir.lib.ncu.edu.tw/handle/987654321/110357 title: 利用液態鎵奈米結構與 PDMS 法布里–珀羅腔體之減色結構色研究;Investigation of Subtractive Structural Colors Using Liquid Gallium Nanostructures and PDMS Fabry–Pérot Cavities abstract: 結構色可透過微奈米結構與光之間的干涉、散射或共振作用產生顏色，不需依賴傳統染料或顏料。本研究以鎵奈米顆粒、稀釋聚二甲基矽氧烷（polydimethylsiloxane， PDMS）薄膜與矽基板組成反射式 Fabry–Pérot cavity，探討 PDMS 膜厚與鎵奈米顆粒尺寸對減色式結構色之影響。實驗透過改變 PDMS 稀釋比例與鎵蒸鍍厚度調整結構參數，並結合反射光譜量測、CIE 1931 色度分析與時域有限差分法模擬，分析其光譜與色彩表現。 結果顯示，PDMS 厚度改變會使反射光譜中的特徵谷值產生位移，進而帶動色度座標移動；鎵奈米顆粒尺寸則會影響反射谷深度、頻寬及色度分布範圍。模擬與實驗結果皆顯示，25 nm 鎵奈米顆粒具有較佳的光譜選擇性與減色式色彩表現。在電場強度分布顯示，光場除分布於 PDMS 腔體內，也集中於鎵奈米顆粒周圍，說明腔體干涉與顆粒的局域光學響應共同參與反射光譜的形成。以 sRGB 色域作為基準計算色彩覆蓋率時，25 nm 樣品之實驗色彩覆蓋率約為 38.87%，高於 10 nm 與 40 nm 樣品，且與模擬結果呈現相同的尺寸變化趨勢。整體而言，鎵奈米顆粒結合可調厚度 PDMS 介電層可形成具有色彩調控能力的反射式 Fabry–Pérot cavity，並提供不同於連續金屬薄膜的結構色設計方式。;Structural colors are generated through interference， scattering， or resonance between light and micro- or nanoscale structures without relying on conventional dyes or pigments. In this study， a reflective Fabry–Pérot cavity composed of gallium nanoparticles， a diluted polydimethylsiloxane (PDMS) film， and a silicon substrate was developed to investigate the effects of PDMS thickness and nanoparticle size on subtractive structural colors. Reflectance spectroscopy， CIE 1931 chromaticity analysis， and finite-difference time-domain (FDTD) simulations were used to evaluate the optical and color characteristics. The results show that PDMS thickness shifts the reflectance dips and corresponding chromaticity coordinates， while nanoparticle size affects the dip depth， bandwidth， and chromaticity distribution. Both simulations and experiments indicate that the 25 nm nanoparticles provide better spectral selectivity and subtractive color performance. Electric-field distributions show optical fields within the PDMS cavity and around the nanoparticles， indicating contributions from both cavity interference and local nanoparticle responses. Relative to the sRGB gamut， the 25 nm sample achieved an experimental color coverage of approximately 38.87%， higher than those of the 10 and 40 nm samples. These results demonstrate a tunable reflective structural-color design that differs from conventional continuous-metal-film cavities. <br> https://ir.lib.ncu.edu.tw/handle/987654321/110353 title: 高效釕基鎳銀雙金屬有機框架衍生催化劑用於酸性與鹼性模擬海水介質中析氫反應之研究;Highly Efficient Ru@NiAg MOF-Derived Catalysts for Hydrogen Evolution in Both Acidic and Alkaline Seawater Media abstract: 隨著能源需求持續增加，傳統化石燃料的大量消耗所造成的環境污染與碳排放問題日益受到重視。為因應能源轉型與減碳需求，氫能因具零碳排放潛力而被視為重要的潔淨能源。近年來，海水電解因可直接利用豐富海洋資源，成為具潛力的永續產氫技術，但仍面臨鹽類沉積、高腐蝕性及電極穩定性不足等挑戰。此外，析氫反應(HER)受限於緩慢的反應動力學，因此開發高效且耐久的電催化觸媒已成為重要研究方向。 本研究採用超聲震盪輔助濕化學法，成功製備可應用於0.5 M硫酸與鹼性模擬海水中的高效HER電催化觸媒，並以金屬有機框架(metal-organic frameworks， MOFs)衍生材料作為載體，建構以釕(Ru)為核心之催化系統。首先，以H3BTC(1，3，5-苯三甲酸)作為有機配體，搭配不同金屬比例合成NixAgy-BTC(x : y = 1:0、1:2、1:1、2:1、0:1)做為基材；隨後透過離子置換方式引入Ru，使其均勻分散於材料中，最後經鍛燒處理以增加孔洞數量與比表面積。Ru與Ni、Ag之協同作用可有效調控氫吸附自由能，而高導電性的Ag則有助於提升電子傳輸效率與反應動力學。此外，多孔結構能提供大量活性位點、優異的離子傳導能力與良好的結構穩定性，進一步提升HER催化活性。後續利用電化學工作站評估其HER性能，並結合X光繞射(XRD)、高解析度穿透式電子顯微鏡(HRTEM)、能量散射X射線光譜(EDS)、X光光電子能譜(XPS)與感應耦合電漿光學發射光譜(ICP-OES)等分析技術，探討材料之元素組成、晶體結構、晶格特徵與元素價態等性質。 在不同組成比例之Ru@NixAgy/C觸媒中，最佳化樣品Ru@Ni2Ag1/C於酸性與鹼性模擬海水中皆展現優異HER性能。在電流密度10 mA cm-2下，其過電位(η10)於酸性與鹼性條件中分別僅需35與12 mV，Tafel斜率則分別為24與18 mV dec¬¬¬-1；經5000圈加速劣化測試後，過電位仍僅增加至49與21 mV，Tafel斜率分別為33與26 mV dec-1，相較於純Ru/C對照組具有更佳之催化活性與穩定性，顯示其具備優異的抗腐蝕能力與長期操作潛力。 此外，透過HRTEM觀察Ru@Ni/C與Ru@Ni2Ag1/C之微觀形貌，可發現Ag元素導入後會驅動其向材料表面擴散，以降低整體表面能，進而改變材料成長方向，使原本「棒狀結構伴隨顆粒聚集」的形貌轉變為「鬆散分枝/海藻狀」結構。此現象屬於表面能驅動之形貌重構，不僅顯著增加反應表面積與活性位點數量，也與HER性能提升結果相互呼應。 綜合以上結果可知，本研究成功開發同時含有Ru、Ni與Ag之多元金屬觸媒系統，可藉由元素間的協同效應有效調控氫吸附行為。其中，Ag的導入除了提升電子傳輸與反應動力學外，亦能誘導形貌重構，大幅提高HER催化活性與穩定性。本研究成果為海水電解產氫技術提供了一項具潛力之觸媒設計策略，並展現未來潔淨能源應用之發展價值。 關鍵字：析氫反應、海水電解、金屬有機框架、鎳、銀、釕基觸媒;With the continuous growth in global energy demand， the extensive consumption of traditional fossil fuels has led to increasing concerns regarding environmental pollution and carbon emissions. To address the needs of energy transition and carbon reduction， hydrogen energy has been regarded as an important clean energy source due to its potential for zero carbon emissions. In recent years， seawater electrolysis has emerged as a promising sustainable hydrogen production technology because of the abundant availability of seawater resources. However， its practical application still faces several challenges， including salt precipitation， severe corrosion， and insufficient electrode stability. In addition， the hydrogen evolution reaction (HER) is intrinsically limited by sluggish reaction kinetics， making the development of highly efficient and durable electrocatalysts an important research focus. In this study， highly efficient HER electrocatalysts applicable to 0.5 M H2SO4 and alkaline simulated seawater were successfully synthesized using an ultrasonic-assisted wet chemical method. Metal–organic framework (MOF)-derived materials were employed as supports to construct a Ru-based catalytic system. First， H3BTC (1，3，5-benzenetricarboxylic acid) was used as the organic ligand， and NixAgy-BTC (x : y = 1:0， 1:2， 1:1， 2:1， and 0:1) precursors were synthesized using different metal ratios as substrates. Subsequently， Ru was introduced through an ion-exchange process to achieve uniform dispersion within the material， followed by calcination to increase the pore quantity and specific surface area. The synergistic interaction among Ru， Ni， and Ag effectively regulated the hydrogen adsorption free energy， while the highly conductive Ag enhanced electron transfer efficiency and reaction kinetics. Furthermore， the porous structure provided abundant active sites， excellent ion transport capability， and superior structural stability， thereby significantly improving HER catalytic activity. Electrochemical measurements were conducted to evaluate HER performance， while X-ray diffraction (XRD)， high-resolution transmission electron microscopy (HRTEM)， energy-dispersive X-ray spectroscopy (EDS)， X-ray photoelectron spectroscopy (XPS)， and inductively coupled plasma optical emission spectroscopy (ICP-OES) were employed to investigate the elemental composition， crystal structure， lattice characteristics， and valence states of the catalysts. Among the Ru@NixAgy/C catalysts with different compositions， the optimized Ru@Ni2Ag1/C sample exhibited outstanding HER performance in both acidic and alkaline simulated seawater. At a current density of 10 mA cm-2， the overpotentials (η10) were only 35 and 12 mV under acidic and alkaline conditions， respectively， while the corresponding Tafel slopes were 24 and 18 mV dec-1. After 5000 accelerated degradation cycles， the overpotentials increased only slightly to 49 and 21 mV， with Tafel slopes of 33 and 26 mV dec-1， respectively. Compared with the pure Ru/C reference catalyst， Ru@Ni2Ag1/C demonstrated superior catalytic activity and stability， indicating excellent corrosion resistance and long-term operational durability. Moreover， HRTEM observations of Ru@Ni/C and Ru@Ni2Ag1/C revealed that the introduction of Ag induced surface diffusion to reduce the overall surface energy， thereby altering the crystal growth direction. As a result， the morphology transformed from a “rod-like structure with aggregated particles” into a “loosely branched/seaweed-like structure.” This phenomenon can be attributed to surface-energy-driven morphological reconstruction， which significantly increased the reaction surface area and the number of active sites， consistent with the observed enhancement in HER performance. Overall， the results demonstrate that the developed multimetallic catalyst system containing Ru， Ni， and Ag can effectively regulate hydrogen adsorption behavior through synergistic effects among the constituent elements. The incorporation of Ag not only improves electron transfer and reaction kinetics but also induces morphological reconstruction， thereby greatly enhancing HER catalytic activity and stability. This study provides a promising catalyst design strategy for seawater electrolysis-based hydrogen production and highlights its potential for future clean energy applications. Keywords: Hydrogen evolution reaction (HER)， Seawater electrolysis， Metal-organic frameworks (MOFs)， Nickel， Silver， Ruthenium-based catalysts <br>