【作者】 韩焕波；

【导师】 董国君；

【作者基本信息】 哈尔滨工程大学 ， 应用化学， 2007， 硕士

【摘要】 本文以TiO₂、TiO₂／堇青石为载体，用水热合成法，经焙烧及KBH₄浸渍等合成了负载型金属催化剂。对以TiO₂为载体的Fe-Ni-B／TiO₂催化剂，通过向其表面负载Ag，改善了该催化剂氢化还原后的抗氧化能力。对Fe-Ni-B／TiO₂／堇青石催化剂的制备工艺进行了深入研究。研究表明，催化剂的最佳合成工艺及条件为：150℃水热合成→500℃焙烧3h→KBH₄浸渍→400℃氢气还原。利用该合成工艺，分别以FeSO₄·7H₂O、Fe（NO₃）₃·9H₂O、FeCl₂·4H₂O、Co（NO₃）₂·6H₂O、CoSO₄·7H₂O、CoCl₂·6H₂O、Ni（NO₃）₂·6H₂O、NiSO₄·6H₂O及NiCl₂·6H₂O为浸渍液，制备了单组分负载型金属催化剂，研究表明，氢化还原后的催化剂催化析氢寿命短，因此，在合成单组分催化剂时未引入氢化还原工艺环节。催化析氢性能结果表明，以Fe（NO₃）₃·9H₂O和CoCl₂·6H₂O为浸渍液所合成的Fe／TiO₂／堇青石催化剂及CoTiO₃／堇青石催化剂催化析氢性能最佳。KBH₄浸渍可明显改善催化剂的催化析氢性能。对Fe／TiO₂／堇青石催化剂而言，KBH₄浸渍过程将催化剂表面的氧化铁还原为单质铁，XRD及XPS测试均表明催化剂真正起到催化析氢性能的活性组分为单质铁；对CoTiO₃／堇青石催化剂而言，催化剂表面的氧化钴阻碍催化剂催化析氢性能，KBH₄浸渍过程将催化剂表面的氧化钴还原为单质钴而脱落，XRD及XPS测试均表明KBH₄浸渍可达到更加充分地利用催化剂表面活性组分CoTiO₃催化析氢的目的。用紫外-可见分光光度法对CoTiO₃／堇青石催化剂表面钴元素的质量百分含量进行测定，研究结果表明，随催化剂表面钴元素含量的增加，催化剂催化析氢性能提高。实验表明，当用过饱和的CoCl₂·6H₂O溶液为浸渍液时，虽然钴元素负载量增大，但是，催化剂在催化析氢过程中活性组分会脱落。当以饱和的CoCl₂·6H₂O溶液为浸渍液时，催化剂基本能得到最佳的催化析氢性能。CoTiO₃／堇青石催化剂具有优良的催化碱性KBH₄溶液水解析氢的性能，当KBH₄溶液中NaOH浓度为18％时，催化析氢性能最佳。原因可能是由于溶液中OH^-浓度的提高，使得KBH₄溶液与催化剂表面的接触状态发生改变，从而改良了KBH₄溶液在催化剂表面的传质效应。SEM表明CoTiO₃／堇青石催化剂表面为颗粒较小的CoTiO₃，比表面积及孔径分布测试表明该催化剂比表面积为5.58m²·g^-1，平均孔径为14.91nm。利用该催化剂催化KBH₄水解析氢，可实现为不同功率的PEFMC动力系统提供氢源。更多还原

【Abstract】 Supported metal catalysts was synthesized with TiO₂ and TiO₂/cordierite as carrier and supporting metal salt by the method of hydrothermal synthesis, then baking at 500℃and soaking in kalium borohydride（KBH₄） solution. For the catalyst of Fe-Ni-B/TiO₂ that using TiO₂ as carrier, it’s performance of preventing oxidation after reduction in H₂ atmosphere has been improved by supporting Ag on the surface of it. In-depth research has been done on the preparation technics for the catalyst of Fe-Ni-B/TiO₂/cordierite. Research shows that the best preparation technics and conditions for the catalyst is hydrothermal synthesis at 150℃→baking at 500℃for 3 h→soaking in KBH₄→reduction in H₂ atmosphere at 400℃. Using this preparation technics and conditions, simplex component supported metal catalysts was prepared by taking FeSO₄·7H₂O, Fe（NO₃）₃·9H₂O, FeCl₂-4H₂O, Co（NO₃）₂·6H₂O, CoSO₄·7H₂O, CoCl₂·6H₂O, Ni（NO₃）₂·6H₂O, NiSO₄·6H₂O and NiCl₂·6H₂O as dipping solution respectively. Study shows that the longevity of service of catalyst was abridged after reduction in H₂ atmosphere, and simplex component supported metal catalysts was prepared without reduction in H₂ atmosphere. Catalytic property for hydrogen evolution shows that the catalysts of Fe/TiO₂/cordierite and CoTiO₃/cordierite which take Fe（NO₃）₃·9H₂O and CoCl₂·6H₂O as dipping solution respectively has the best catalytic property for hydrogen evolution.Catalytic property for hydrogen evolution has been improved obviously by soaking the catalyst in KBH₄. For the catalyst of Fe/TiO₂/cordierite, in the course of the catalyst soaking in KBH₄, the ferric oxide was deoxidized as elementoid iron, and XRD and XPS all show that the component of elementoid iron has the Catalytic property for hydrogen evolution. For the catalyst of CoTiO₃/cordierite, powder blue on the surface of the catalyst cumber the catalytic property for hydrogen evolution, but the KBH₄ can deoxidize the powder blue as elementoid cobalt and the elementoid cobalt can fall off from the surface of the catalyst, XRD and XPS all show that soaking the catalyst in KBH₄ can achieve the aim of using the activity component of CoTiO₃ catalyze hydrogen evolution adequately.The content of Co on the surface of the catalyst of CoTiO₃/cordierite was determined by ultraviolet-spectrometer, the result of research shows that as the increasing of the content of Co on the surface of the catalyst, the catalyst has higher performance of catalyze hydrogen evolution. Experiment shows that when taking saturated CoCl₂·6H₂O as dipping solution, the catalyst can achieve the best catalytic property for hydrogen evolution on the whole, when taking supersaturation CoCl₂·6H₂O as dipping solution, the supporting capacity manifold, but the activity component will fall off when catalyze hydrogen evolution.The catalyst of CoTiO₃/cordierite has excellent performance of catalytic hydrolysis in alkaline, especially when the kalium borohydride solution with approximate 18% NaOH, it has the best performance of catalyze hydrogen evolution. The reason for that maybe because as the concentration increasing, the tangent state between the solution of KBH₄ and the surface of the catalyst changed, so the flowing impact of the solution of KBH₄ on the surface of the catalyst has been improved.SEM shows that the surface of the catalyst is sheet CoTiO₃ that thickness is many decades nanometer, ratio surface area and aperture distributing test show that the ratio surface area of the catalyst is 5.58 m²·g^-1, average aperture distributing is 14.91 nm.更多还原