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Activity and characterization studies in methanol reforming catalysis: copper and copper-zinc oxide catalysts and the role of nanomaterials.

機(jī)譯：在甲醇重整催化中的活性和表征研究：銅和銅鋅氧化物催化劑以及納米材料的作用。

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Hydrogen storage is a major barrier to commercialization of proton exchange membrane (PEM) fuel cell powered automobiles. The problem can be circumvented by storing a liquid hydrogen source and then using a reforming reaction to generate hydrogen onboard the vehicle. Methanol is the preferred liquid hydrogen source for onboard generation. Methanol steam reforming is a convenient way to generate large amounts of clean hydrogen at reasonable temperatures and atmospheric pressure. Cu and CuO-ZnO reforming catalysts on Al2O 3, ZrO2/Al2O3, and CeO2/Al 2O3 nanoparticle oxide supports were investigated in this work. These systems ranged from traditional impregnated CuO-ZnO/Al2O 3 to more complex CuO-ZnO on mixed nanoparticle ZrO2/Al 2O3 supports. Finally, binary CuO/ZrO2 systems were constructed using a reverse microemulsion procedure.;Detailed reaction studies were performed and kinetic reaction data was examined and compared to surface, structural and electronic characterization data in order to determine both structural and valence state information of the catalyst system before and after reaction. In all cases it was determined that a reasonable Cu surface area is necessary to catalyze the reforming reaction but that high Cu surface area is not the critical criterion for highly active reforming catalysts. It was shown that using nanoparticle Al2O 3 supports can greatly increase catalyst surface area but that Al 2O3 has a retarding effect on catalytic activity which partially offsets any benefits. Therefore it was concluded that Al2O 3 should only be used in relatively low concentrations or in conjunction with another oxide support.;It was determined that an electron deficient Cu species formed due to an interaction with the nanoparticle ZrO2 support which was highly beneficial for catalyst performance. This electron deficient Cu species promoted the methanol reforming reaction while also apparently suppressing CO production via the reverse water gas shift. This work demonstrates that the Cu-ZrO 2 synergy can be exploited by using binary reforming catalysts and is increased by using calcination temperatures above 300°C, despite a slight loss of Cu surface area at high calcinations temperatures.
機(jī)譯：氫存儲(chǔ)是質(zhì)子交換膜（PEM）燃料電池驅(qū)動(dòng)的汽車商業(yè)化的主要障礙。可以通過存儲(chǔ)液態(tài)氫源然后使用重整反應(yīng)在車輛上產(chǎn)生氫來解決該問題。甲醇是用于船載發(fā)電的優(yōu)選液態(tài)氫源。甲醇蒸汽重整是在合理的溫度和大氣壓下產(chǎn)生大量清潔氫氣的便捷方法。在這項(xiàng)工作中研究了在Al2O 3，ZrO2 / Al2O3和CeO2 / Al 2O3納米顆粒氧化物載體上的Cu和CuO-ZnO重整催化劑。這些系統(tǒng)的范圍從傳統(tǒng)的浸漬CuO-ZnO / Al2O 3到混合納米顆粒ZrO2 / Al 2O3載體上的更復(fù)雜的CuO-ZnO。最后，使用反向微乳液程序構(gòu)建了二元CuO / ZrO2系統(tǒng)。;進(jìn)行了詳細(xì)的反應(yīng)研究，并檢查了動(dòng)力學(xué)反應(yīng)數(shù)據(jù)并將其與表面，結(jié)構(gòu)和電子表征數(shù)據(jù)進(jìn)行比較，以確定催化劑的結(jié)構(gòu)和價(jià)態(tài)信息系統(tǒng)反應(yīng)前后。在所有情況下，已經(jīng)確定合理的Cu表面積對于催化重整反應(yīng)是必要的，但是高Cu表面積并不是高活性重整催化劑的關(guān)鍵標(biāo)準(zhǔn)。結(jié)果表明，使用納米顆粒Al2O 3載體可以大大增加催化劑的表面積，但是Al 2O3對催化活性具有阻滯作用，這部分抵消了任何益處。因此得出結(jié)論，僅應(yīng)以相對低的濃度或與另一種氧化物載體結(jié)合使用Al2O 3 ；;已確定由于與納米顆粒ZrO2載體的相互作用而形成了缺電子的Cu物種，這對催化劑性能非常有利。這種缺乏電子的Cu物種促進(jìn)了甲醇重整反應(yīng)，同時(shí)顯然還通過反向水煤氣變換抑制了CO的產(chǎn)生。這項(xiàng)工作表明，盡管在高煅燒溫度下銅表面積略有損失，但通過使用二元重整催化劑可以利用Cu-ZrO 2協(xié)同作用，而通過使用高于300°C的煅燒溫度可以提高Cu-ZrO 2的協(xié)同作用。

著錄項(xiàng)

  • 作者

    Jones, Samuel David.;

  • 作者單位

    University of Florida.;

  • 授予單位 University of Florida.;
  • 學(xué)科 Engineering Chemical.
  • 學(xué)位 Ph.D.
  • 年度 2008
  • 頁碼 148 p.
  • 總頁數(shù) 148
  • 原文格式 PDF
  • 正文語種 eng
  • 中圖分類
  • 關(guān)鍵詞

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