Mass transport in nanoarray monolithic catalysts: An experimental-theory study
Mass transport in nanoarray monolithic catalysts: An experimental-theory study
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DOI：
10.1016/j.cej.2020.126906
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发表时间：
2021-02
影响因子：
15.1
通讯作者：
Xingxu Lu;Wenxiang Tang;Meilin Li;Yanliu Dang;Norwyn Campbell;Zihao Li;S. Suib;P. Gao
中科院分区：
文献类型：
--
作者：
Xingxu Lu;Wenxiang Tang;Meilin Li;Yanliu Dang;Norwyn Campbell;Zihao Li;S. Suib;P. Gao
整体降低催化剂的传质阻力是提高催化反应动力学和充分利用催化剂活性的关键。尽管在广泛研究的水洗衣单体中成功地裁剪了外部传质，但由于要求在保持高比表面积和机械稳定性的同时增加宏观孔隙率，因此很难降低内部传质阻力。因此，纳米结构阵列整体式催化剂（纳米阵列催化剂）作为一种很有前途的结构催化剂，在过去的十年中得到了发展，它可以补充或替代涂层催化剂。本工作通过实验测量和理论建模的结合，从根本上阐明了纳米阵列单片催化剂增强的质量输运特性。利用低维模型，基于c2h4在tio2负载的pt基单片催化剂上氧化的探针模型，从化学动力学、内外传质等方面量化了电阻的相对贡献。由于纳米阵列催化剂的高孔隙率和小厚度，其内部传质阻力较低。纳米阵列结构为设计具有低内扩散限制的高性能整体反应器和催化剂提供了新的途径。
Reducing the mass transfer resistance globally of a catalyst is a key to enhancing the catalytic reaction kinetics and fully utilizing the catalyst activity. Despite the success in tailoring the external mass transfer in the widely studied washcoat monoliths, the internal mass transfer resistance is difficult to be reduced due to the requirement of increasing macroporosity while maintaining high specific surface area and mechanical stability. Therefore, nanostructured array-based monolithic catalysts (nanoarray catalysts) have been developed in the past decade as a promising class of structured catalysts that may complement or substitute washcoat catalysts. This work fundamentally elucidates the enhanced mass transport properties of the nanoarray monolithic catalysts by a combination of experimental measurements and theoretical modeling. Using a low-dimensional model, the relative contributions of resistances were quantified in terms of chemical kinetics, internal and external mass transfers based on a probe model of C2H4oxidation over the TiO2supported Pt-based monolithic catalysts. The nanoarray catalysts displayed a lower internal mass transfer resistance than the washcoat counterparts as a result of the high macroporosity and small thickness of nanoarray layers. The nanoarray configuration provides a new pathway towards designing high-performance monolithic reactors and catalysts with low internal diffusion limitations for various gas phase reactions.