開發新穎三元金屬–有機架構化合物作為析氧反應之 高性能電催化劑;Novel Trimetallic Metal-Organic Framework as High Performance Electrocatalysts for Oxygen Evolution Reaction

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/94696

Title:	開發新穎三元金屬–有機架構化合物作為析氧反應之高性能電催化劑;Novel Trimetallic Metal-Organic Framework as High Performance Electrocatalysts for Oxygen Evolution Reaction
Authors:	馮瑄;Feng, Hsuan
Contributors:	化學學系
Keywords:	三元金屬;有機架構化合物
Date:	2024-07-29
Issue Date:	2024-10-09 15:24:37 (UTC+8)
Publisher:	國立中央大學
Abstract:	近年來，由於環保意識的興起，為解決能源危機和環境污染的問題，電催化分解水產氫技術已成為熱門的研究議題。全電解水的過程，是由兩個半反應所組成，其中析氧反應需經過四個電子的轉移及氧氧化學鍵的形成過程，反應動力學相當緩慢，需要額外提供更高的能量才能跨越反應所需之活化能，成為在總反應中之反應瓶頸。金屬–有機架構化合物(Metal–organic frameworks, MOF)具有高表面積以及高孔隙率，同時金屬離子可均勻分佈於結構中，為 OER 電催化反應提供豐富的金屬活性位點。本篇論文中，先以水熱合成法，成功合成新穎的 C-MOF(鈷 MOF)，利用單晶 X-ray 繞射儀(SCXRD) 解析其固態晶體結構。C-MOF 可以應用為OER 催化劑，並以原位生長方式成功合成二元及三元的CN-MOF(鈷鎳MOF)及FCN-MOF(鐵鈷鎳MOF)，在1 M 的KOH 中研究協同效應對其電催化效能之影響。催化劑中金屬活性位點上的電子密度分佈，在電催化活性上扮演著關鍵角色。本篇論文中，我們亦透過簡單的白金奈米粒子(Pt nanoparticles, Pt NPs)修飾來微調中心金屬的電子組態，進而有效降低發生OER 反應時所需之額外能量，並利用粉末X-ray 繞射儀(PXRD)、掃描式電子顯微鏡(SEM)、穿透式電子顯微鏡(TEM)、感應耦合電漿光學發射光譜儀(ICP-OES)以及高解析光電子能譜儀(XPS)確認其性質。與未經修飾的三元 FCN-MOF 相比，經過 Pt NPs 修飾的FCN-MOF-Pt1 具有較佳的電催化表現，η10 和η500 分別從204 和261 mV 分別降低到 182 和 244 mV。過電位的降低，可歸因於高電負度的Pt NPs 修飾後，鐵、鈷和鎳的氧化態會顯著升高所導致。並且 FCN- MOF-Pt1 在500 mA cm−2 的高電流密度下，持續工作 50 小時後，電流密度僅降低 7%，這優異的結果可歸因於合成時採用原位成長方式，將 MOF 直接生長於泡沫鎳的骨架上可以更加穩定，且在高電流密度下能有更出色的耐受性。;In recent years, the urgent need to address climate change necessitates the phasing out of fossil fuels by 2050. To tackle the dual challenges of energy crises and environmental pollution, electrocatalytic water splitting for hydrogen production has emerged as a key research area. This process involves two half-reactions, with the oxygen evolution reaction (OER) being particularly crucial due to its slow kinetics and high energy requirements. Metal–organic frameworks (MOFs), characterized by high surface area and porosity, uniformly distribute metal ions, providing abundant active sites for OER. In this study, a novel C-MOF was synthesized using hydrothermal methods and analyzed with single-crystal X-ray diffraction (SCXRD). Further, di-metallic CN-MOF and tri-metallic FCN- MOF were synthesized via in-situ growth and applied as OER catalysts. The synergistic effects among iron (Fe), cobalt (Co), and nickel (Ni) were investigated in 1 M KOH. The electronic states of the catalysts′ active sites were found to be critical in determining their electrocatalytic performance. Additionally, platinum was deposited onto FCN-MOF using a simple sputtering method to adjust the electronic configuration of the active metal centers, thereby reducing the energy required for the OER. Characterization using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), inductively coupled plasma optical emission spectrometry (ICP-OES), and high-resolution X-ray photoelectron spectroscopy (HRXPS) confirmed these modifications. Compared to the unmodified tri-metallic FCN-MOF, the platinum-modified FCN-MOF-Pt1 exhibited superior electrocatalytic performance, with η10 and η500 reduced from 204 mV and 261 mV to 182 mV and 244 mV, respectively. The decrease in overpotential is attributed to theelevated oxidation states of Fe, Co, and Ni induced by the highly electronegative platinum. Moreover, after continuous operation at a high current density of 500 mA cm−2 for 50 hours, the current density of FCN-MOF-Pt1 decreased by only 7%. This stability is attributed to the in-situ growth method, which provides enhanced stability and tolerance under high current densities by growing the MOF directly on the nickel foam skeleto
Appears in Collections:	[Graduate Institute of Chemistry] Electronic Thesis & Dissertation

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