Mechanistic insights into the catalytic methanol steam reforming performance of Cu/ZrO2 catalysts by in situ and operando studies
Mechanistic insights into the catalytic methanol steam reforming performance of Cu/ZrO2 catalysts by in situ and operando studies
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DOI：
10.1016/j.jcat.2020.09.018
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发表时间：
2020-11-01
影响因子：
7.3
通讯作者：
Penner, Simon
中科院分区：
文献类型：
--
作者：
Ploner, Kevin;Watschinger, Maximilian;Penner, Simon
我们评估了Cu/ZrO 2界面在粉末催化剂上甲醇和甲醛蒸汽重整（MSR和FSR）中的催化性能，通过使用比较方法，考察了ZrO 2多晶型载体结构（单斜（m-）ZrO 2与四斜（t-）ZrO 2）、其合成程序和前体材料对CO2选择性的影响。我们的研究表明，ZrO 2表现出显着的多功能性作为载体材料，其催化性能最强烈地依赖于其合成，特别是由Zr前体的选择，其表面性质。将载体与铜结合的方式引入了额外的复杂性层，但其对MSR性能的影响限于对由ZrO 2载体提供的条件的修改。利用关于FSR和MSR中的Cu-ZrO 2催化剂的比较方法-包括纯载体材料-结合原位傅里叶变换红外（FT-IR）光谱显示，在Cu/m-ZrO 2上的MSR中观察到的CO可以归因于甲醛溢出到载体。m-ZrO 2的副反应在较低的温度下被抑制，由于其缺乏高活性位点，导致CO2选择性MSR性能。然而，在Cu/t-ZrO 2中，CO的量较高，并且甲醛溢出到载体和产生CO的Cu-ZrO 2相边界的组合导致这些样品的较低的CO2选择性。与Cu/m-ZrO 2催化剂相比，t-ZrO 2的缺陷和反应性刘易斯酸性和布朗斯台德碱性中心的数量增加解释了这种增加的对副反应的活性。(C)2020由Elsevier Inc.出版。
We assessed the catalytic properties of the Cu/ZrO2 interface in methanol and formaldehyde steam reforming (MSR and FSR) on powder catalysts by using a comparative approach with respect to the influence of the ZrO2 polymorph support structure (monoclinic (m-)ZrO2 vs. tetragonal (t-)ZrO2), its synthesis routine and the choice of the precursor material on the CO2 selectivity. Our studies reveal that ZrO2 exhibits a pronounced versatility as a support material and its catalytic properties depend most strongly on its surface properties governed by its synthesis, especially by the choice of the Zr precursor. The way of combining the support with copper introduces an additional layer of complexity, but its influence on the MSR performance is limited to a modification of the conditions provided by the ZrO2 support. Exploiting the comparative approach regarding the Cu-ZrO2 catalysts in FSR and MSR - including the pure support materials - in combination with in situ Fourier transform infrared (FT-IR) spectroscopy shows that the CO observed in MSR on Cu/m-ZrO2 can be attributed to a spillover of formaldehyde to the support. Side reactions of m-ZrO2 are suppressed at lower temperatures due to its lack of highly reactive sites, resulting in a CO2-selective MSR performance. In Cu/t-ZrO2, however, the amount of CO is higher and a combination of a formaldehyde spillover to the support and a Cu-ZrO2 phase boundary yielding CO leads to the lower CO2 selectivity of these samples. An elevated number of defects and reactive Lewis acidic and Bronsted basic centers of t-ZrO2 explains this increased activity towards side reactions in contrast to Cu/m-ZrO2 catalysts. (C) 2020 Published by Elsevier Inc.