国产bbaaaaa片,成年美女黄网站色视频免费,成年黄大片,а天堂中文最新一区二区三区,成人精品视频一区二区三区尤物

首頁(yè)> 外文學(xué)位 >Manganese Promoted CO Hydrogenation Catalysts: A Study of Metal Promoter Interaction Effects.
【24h】

Manganese Promoted CO Hydrogenation Catalysts: A Study of Metal Promoter Interaction Effects.

機(jī)譯：錳促進(jìn)的CO加氫催化劑：金屬促進(jìn)劑相互作用的研究。

獲取原文
獲取原文并翻譯 | 示例
  • 摘要
  • 著錄項(xiàng)
  • 相似文獻(xiàn)
  • 相關(guān)主題

摘要

The aim of the work described in this thesis is to investigate the rational design of promoted metal catalysts for CO hydrogenation reactions. The main body of this work focuses on the use of simple techniques and common elemental precursors to improve the interactions in between a promoter and active metal. One of the many ways of achieving this is through the use of Strong Electrostatic Adsorption (SEA). Special attention to the surface charging parameters of mixed oxide as a function of solution pH can create a driving force to selectively adsorb a precursor complex onto a single phase of a binary mixture.;The use of promoters is ubiquitous in CO hydrogenation reactions to increase active metal's activities as well as the selectivity towards desired products. Although, the precise active site of promoters in reactions and how they interact with active metals to react the reactants require many more studies, it is agreed that a key design objective is to increase the metal-promoter interactions. This work demonstrates a procedure to achieve this with Mn promoter catalysts.;In Chapter 1, we present an introduction and a brief review of CO hydrogenation catalysts for both the conversion of syngas to alcohols (particularly ethanol) and, additionally the conversion of syngas to long-chained hydrocarbons in a typical Fischer- Tropsch (FT) reaction. In Chapter 2, the fundamentals of the Transmission Electron Microscope (TEM) and its applications on catalysis related projects are presented. Chapter 3 gives a detailed discussion for rational design to selectively adsorb a [MnO4]- promoter precursor over a Rh2O3/SiO2 supported catalyst. Various techniques (ICP, STEM-EELS, XANES, EXAFS, TPR) were utilized to study the intrinsic properties of the catalysts and how the different catalysts preparation method could affect the metalpromoter interactions. The alcohol (ethanol) synthesis reactivity measurement also gave us key insight to the role of the promoter as a function of metal-promoter interactions. In Chapter 4, we focus on the rational design of the selective adsorption of a [MnO4]- precursor over a Co3O4/TiO2 supported catalyst, in this study, catalysts with three metalpromoter interactions (namely Mn monolayer coverage on Co, Mn partial coverage on Co and least Mn interaction with Co) were made and the different metal-promoter interactions were visualized by the STEM-EELS analysis, the F-T reactivity results demonstrated that the catalyst which has the strongest Mn-Co interaction (Mn monolayer coverage on Co) has the highest selectivity towards C5+ hydrocarbons (desired product). In Chapter 5, we continue discussing the CO hydrogenation for alcohol synthesis (especially ethanol). However in this chapter, we studied the metal-promoter interaction effects over Mn promoted Rh catalysts supported on multi-walled carbon nanotubes (CNTs) by just using the normal impregnation (DI, dry impregnation) catalysts preparation method. The enhanced Mn interaction with Rh particles was achieved by increasing the Mn loading (2 wt% Mn vs 1 wt% Mn loading), and the enhancement was visualized and quantified by STEM-EELS analysis due to the virtue of CNTs support (low Z number of C). Once again, in the reactivity results, the catalyst with stronger Mn- Rh interactions exhibited higher selectivity towards ethanol.;This thesis ends with main conclusion that the key of rational catalysts design is to enhance the metal-promoter interactions, which can be achieved by either selectively adsorbing promoter onto the active metal or simply increasing the promoter loading by impregnation method. By focusing the intrinsic principles of catalyst preparation, this concept of stronger metal-promoter interactions can be applied to a wide range of catalytic materials to help define the promoter's precise roles in various catalytic reactions.
機(jī)譯：本文所描述的工作目的是研究用于CO加氫反應(yīng)的促進(jìn)型金屬催化劑的合理設(shè)計(jì)。這項(xiàng)工作的重點(diǎn)是使用簡(jiǎn)單的技術(shù)和常見的元素前體來改善促進(jìn)劑和活性金屬之間的相互作用。實(shí)現(xiàn)此目的的許多方法之一是通過使用強(qiáng)靜電吸附（SEA）。特別注意混合氧化物的表面電荷參數(shù)隨溶液pH的變化會(huì)產(chǎn)生驅(qū)動(dòng)力，以選擇性地將前體復(fù)合物吸附到二元混合物的單相上;在CO加氫反應(yīng)中普遍使用促進(jìn)劑來增加活性金屬的活性以及對(duì)所需產(chǎn)品的選擇性。盡管促進(jìn)劑在反應(yīng)中的精確活性位點(diǎn)以及它們?nèi)绾闻c活性金屬相互作用以使反應(yīng)物發(fā)生反應(yīng)還需要進(jìn)行大量研究，但公認(rèn)的主要設(shè)計(jì)目標(biāo)是增加金屬-促進(jìn)劑的相互作用。這項(xiàng)工作展示了用Mn助催化劑實(shí)現(xiàn)這一目標(biāo)的程序。在第一章中，我們對(duì)用于將合成氣轉(zhuǎn)化為醇（尤其是乙醇）以及另外將合成氣轉(zhuǎn)化為CO的CO加氫催化劑進(jìn)行了介紹和簡(jiǎn)要介紹。典型的費(fèi)-托（FT）反應(yīng)中的長(zhǎng)鏈烴。在第二章中，介紹了透射電子顯微鏡（TEM）的基本原理及其在催化相關(guān)項(xiàng)目中的應(yīng)用。第三章詳細(xì)討論了合理設(shè)計(jì)，以在Rh2O3 / SiO2負(fù)載的催化劑上選擇性吸附[MnO4]-促進(jìn)劑前體。利用各種技術(shù)（ICP，STEM-EELS，XANES，EXAFS，TPR）研究了催化劑的固有性質(zhì)，以及不同催化劑的制備方法如何影響金屬促進(jìn)劑的相互作用。醇（乙醇）合成反應(yīng)性的測(cè)量也使我們對(duì)促進(jìn)劑作為金屬-促進(jìn)劑相互作用的作用有了重要的認(rèn)識(shí)。在第4章中，我們著重于[MnO4]-前體在Co3O4 / TiO2負(fù)載的催化劑上的選擇性吸附的合理設(shè)計(jì)，在本研究中，該催化劑具有三種金屬促進(jìn)劑相互作用（即Co上的Mn單層覆蓋，Co上的Mn部分覆蓋）。進(jìn)行了Co和最少的Mn與Co的相互作用，并通過STEM-EELS分析顯示了不同的金屬-促進(jìn)劑相互作用，F(xiàn)T反應(yīng)性結(jié)果表明，具有最強(qiáng)的Mn-Co相互作用（Co上的Mn單層覆蓋）的催化劑具有對(duì)C5 +烴（所需產(chǎn)物）的最高選擇性。在第5章中，我們繼續(xù)討論用于醇合成（特別是乙醇）的CO加氫。然而，在本章中，我們僅使用常規(guī)浸漬（DI，干浸漬）催化劑的制備方法，研究了多壁碳納米管（CNT）上負(fù)載的Mn促進(jìn)Rh催化劑上金屬-促進(jìn)劑的相互作用。通過增加Mn的負(fù)載量（2 wt％的Mn與1 wt％的Mn的負(fù)載）可以增強(qiáng)與Rh顆粒的Mn相互作用，由于碳納米管的支持（低Z值），通過STEM-EELS分析可以直觀地看到和量化這種增強(qiáng)作用C）。再次，在反應(yīng)性結(jié)果中，具有更強(qiáng)Mn-Rh相互作用的催化劑對(duì)乙醇表現(xiàn)出更高的選擇性。選擇性地將促進(jìn)劑吸附到活性金屬上，或通過浸漬法簡(jiǎn)單地增加促進(jìn)劑的負(fù)載量。通過關(guān)注催化劑制備的內(nèi)在原理，這種更強(qiáng)的金屬-促進(jìn)劑相互作用概念可以應(yīng)用于各種催化材料，以幫助確定助催化劑在各種催化反應(yīng)中的精確作用。

著錄項(xiàng)

  • 作者

    Liu, Jingjing.;

  • 作者單位

    University of Illinois at Chicago.;

  • 授予單位 University of Illinois at Chicago.;
  • 學(xué)科 Engineering Chemical.;Alternative Energy.
  • 學(xué)位 Ph.D.
  • 年度 2014
  • 頁(yè)碼 176 p.
  • 總頁(yè)數(shù) 176
  • 原文格式 PDF
  • 正文語種 eng
  • 中圖分類 遙感技術(shù);
  • 關(guān)鍵詞

相似文獻(xiàn)

  • 外文文獻(xiàn)
  • 中文文獻(xiàn)
  • 專利
獲取原文

客服郵箱：kefu@zhangqiaokeyan.com

京公網(wǎng)安備：11010802029741號(hào) ICP備案號(hào)：京ICP備15016152號(hào)-6 六維聯(lián)合信息科技 (北京) 有限公司?版權(quán)所有

  • 客服微信

  • 服務(wù)號(hào)