GOALI: Novel Impregnated Layer Combustion Synthesis for Catalysts Preparation: Hydrogen Production from Methanol

Eduardo E.Wolf0730190这项工作的动机是需要找到一种可控的制备方法来制备用于小型燃料电池的甲醇氧化重整制氢的高比表面积金属/氧化物催化剂。本研究的目的有两个：1)研究一种新的基于溶液燃烧合成的催化剂制备方法，称为浸渍层燃烧合成(ILCS)；2)发展用ILCS方法制备的用于ORM反应的催化剂的结构-活性关系，并进行光谱研究以确定活性中心并将这些活性中心与表面和材料性质联系起来。PIS小组的初步研究表明，共沉淀法制备的Pd/Cu/ZnO/ZrO2催化剂对ORM反应具有良好的活性和选择性。PI还确定了铜的金属表面积和氧化态是活性和选择性的决定因素。ILCS方法已经证明可以得到高比表面积的氧化物以及负载在高面积氧化物上的金属。ILCS方法涉及反应前沿在狭窄区域内的短时间受控传播，随着气体的释放，抑制了颗粒尺寸的增长，导致形成高比表面积(50-200m2/g)、高纯度和结晶度的氧化物，而不需要额外的焙烧。提供了一个概念证明，通过使用ILCS，他们能够合成一种具有类似于共沉淀催化剂的高活性和高选择性的催化剂。对ILCS方法的进一步研究有望产生更高的活性区域，并提高活性和选择性。在上述结果的基础上，他们假设：1)基本了解ILCS的制备变量如何影响材料性能将导致设计出活性和选择性的ORM反应催化剂；2)建立ORM反应的结构-活性关联可以导致合理设计活性更高和选择性更高的氧化催化剂。为了研究ILCS中使用的制备变量(溶液浓度、燃料成分、衬底浸渍、点火温度)如何影响块体材料和表面性质，如总表面积和活性表面积、结晶度、物相组成、助剂的分散性和不同环境下的氧化状态，计划进行详细的研究。由ILCS制备的各种催化剂的活性和选择性结果将通过各种先进技术进行评估。将详细测量所选催化剂的动力学，以与材料性质和制备变量相关联。所选催化剂的EXAFS和IR光谱将用来确定催化剂在反应条件下的氧化状态和吸附类型，并确定影响活性和选择性的关键表面变量(S)。然后，动力学研究的速率常数将与关键表面性质相关联，进而与ILCS制备变量相关联。所得结果将为氧化催化剂的合理设计提供新的思路和方法，同时也为研究决定ORM产氢的因素提供了新的思路。智力上的好处是，通过PI的综合专业知识，将在催化剂合成领域获得新的知识，用于解决目前具有相当大的社会重要性和可能产生广泛技术影响的问题。拟议的综合计划将通过REU拨款整合研究生和本科生两个层面的研究。计划通过拨出资金支持巴黎圣母院少数族裔工程项目的努力，帮助增加工程专业中代表性不足群体的招聘，从而产生更广泛的教育影响。这笔资金将支持一项外展计划，将潜在的学生带到巴黎圣母院，并让他们参与与这项提议相关的实验。

Eduardo E. Wolf0730190This work is motivated by the need to find a controllable preparation method of high surface area metal/oxide catalysts for the production of hydrogen from the oxidative reforming of methanol (ORM) for small fuel cell applications. The objective of the research is twofold: 1) to study a novel method for catalyst preparation based on solution combustion synthesis, referred to as Impregnated Layer Combustion Synthesis, or ILCS, and, 2) develop structure-activity correlations of catalysts prepared by the ILCS method for the ORM reaction along with spectroscopic studies to identify active sites and links those with surface and material properties. Preliminary studies conducted in the PIs groups' show that Pd/Cu/ZnO/ZrO2 catalysts prepared by co-precipitation are active and selective for the ORM reaction. The PIs have also identified the Cu metal surface area and oxidation state as determining factors of activity and selectivity. The ILCS method has shown to yield high surface area oxides as well as metals supported onto high area oxides. The ILCS method involves the controlled propagation of a reaction front in a narrow area for a short time, which along with the evolution of gases, inhibits particle size growth leading to the formation of oxides of high surface area (50-200 m2/g), high purity and crystallinity, which do not require additional calcination. A proof of concept is provided that by using ILCS they were able to synthesize a catalyst that has high area and activity and selectivity similar to co-precipitated catalyst. Further studies of the ILCS method are expected to yield even higher active areas and increase activity and selectivity. On the basis of the above results they hypothesize that i) Fundamental understanding of how preparative variables of ILCS affect material properties will lead to the design of active and selective catalysts for the ORM reaction, ii) Establishing structure-activity correlations for ORM reactions could lead to the rational design of more active and selective oxidation catalysts. A detailed program is planned to study how the preparative variables used in ILCS (solution concentration, fuel composition, substrate impregnation, ignition temperature) affect the bulk material and surface properties such as total and active surface area, degree of crystallinity, phase composition, dispersion of promoters, and oxidation state under different environments. Activity and selectivity results for various catalysts prepared by ILCS will be evaluated by various advanced techniques. The kinetics of selected catalysts will be measured in detail for correlation with the material properties and preparative variables. EXAFS and IR spectroscopy of selected catalysts will be used to determine the catalysts' oxidation state and type of adsorbates under reaction conditions (operando) and to determine the key surface variable(s) responsible for activity and selectivity. The rate constants from the kinetics studies will be then correlated with the key surface properties and these in turn with the ILCS preparative variables. The results obtained will provide new knowledge of the novel ILCS as a method for the rational design of oxidation catalysts as well as the factors determining hydrogen production from the ORM. The intellectual merit is that through the combined expertise of the PIs, new knowledge will be gained in the field of catalysts synthesis applied to the problem that is currently of considerable societal importance and could have a broad technical impact. The comprehensive program proposed will integrate research at both the graduate level, and at undergraduate level via REU grants. A broader educational impact is planned by setting aside funds for supporting the effort of the minority engineering program at Notre Dame to help increase recruiting of underrepresented groups in engineering. The funds will support an outreach program to bring prospective students to Notre Dame and have them participate on experiments related to this proposal.