One-Shot Measurement of Effectiveness Factors of Chemical Conversion in Porous Catalysts
One-Shot Measurement of Effectiveness Factors of Chemical Conversion in Porous Catalysts
复制标题
DOI：
10.1002/cctc.201801530
复制
发表时间：
2018-12-21
期刊：
影响因子：
4.5
通讯作者：
Kaerger, Joerg
中科院分区：
文献类型：
--
作者：
Chmelik, Christian;Liebau, Michael;Kaerger, Joerg
从多相催化的早期开始，高表面积固体就被广泛用于获得最大可能的活性位点密度，并相应地最大化周转率。由于只有当位点被反应物（即仍待转化的分子）占据时，位点才是真正意义上的活性位点，因此反应物占据的孔体积的相对分数（有效性因子）是给定反应中催化剂效率的关键数字。迄今为止，其确定通常基于有目的地改变催化剂颗粒的反应速率测量，但迄今为止仍然是一项具有挑战性的任务，因为它必须基于额外的假设。通过红外显微成像一次性确定有效性因子，这里以考虑分散在纳米多孔玻璃上的铂催化苯氢化为环己烷为例，被证明开辟了一条克服这些限制的有希望的途径。
From the earliest days of heterogeneous catalysis, high surface area solids were extensively used for attaining largest possible densities of active sites and, correspondingly, for maximizing turnover. Since sites are active in the real sense of the word only if they are occupied by reactants, i.e., by molecules still to be converted, the relative fraction of pore volume occupied by reactants (the effectiveness factor) is a key number for the efficiency of a catalyst in a given reaction. Its determination, so far generally based on reaction rate measurements with purposefully varied catalyst particles, remained to date a challenging task since it must be based on additional assumptions. The one-shot determination of effectiveness factors by IR microimaging, here exemplified on considering the catalytic hydrogenation of benzene to cyclohexane by platinum dispersed on nanoporous glass, is shown to open up a promising route to overcome these limitations.