通过疏水改性提高铜基催化剂在甲醇合成中的热稳定性

IF 2.8 4区 工程技术 Q2 ENGINEERING, CHEMICAL
Processes Pub Date : 2024-09-18 DOI:10.3390/pr12092008
Futao Ma, Jingjing Liu, Kaixuan Chen, Zhenmin Cheng
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引用次数: 0

摘要

水会导致铜基催化剂表面的铜纳米颗粒生长和氧化,从而导致催化剂失活。然而,在铜基催化剂利用合成气合成甲醇的过程中,由于二氧化碳的存在,不可避免地会产生水作为副产品。因此,提高铜基催化剂在反应过程中的稳定性至关重要,尤其是在有水存在的情况下。在本研究中,首先对 Cu/ZnO/Al2O3 进行了湿法蚀刻,然后使用甲基三甲氧基硅烷 (MTMS) 溶胶凝胶法和 1H,1H,2H,2H-全氟烷基三乙氧基硅烷 (PFOTES) 接枝法作为改性剂对其进行疏水改性。这些改性旨在减轻水对催化剂的影响并提高其稳定性。改性后的催化剂在甲醇合成过程中表现出优异的疏水性和更高的催化活性。通过 SEM、FT-IR、BET、XRD 和 TGA 对疏水改性前后催化剂的表面物理性质、组成和热稳定性进行了表征。此外,还利用分子动力学模拟比较了疏水改性前后催化剂表面水分子的扩散行为。结果表明,改性后的催化剂表面形成了由纳米片和纳米片簇组成的微/纳米结构,而疏水改性并没有改变催化剂的结构。模拟结果表明,改性催化剂表面的疏水层能够迅速将水分排出表面,降低活性位点的水分子相对浓度,从而提高催化剂的稳定性。值得注意的是,PFOTES 改性催化剂的热稳定性和疏水性均优于 MTMS 改性催化剂,从而更显著地提高了催化剂的稳定性,这与实验结果一致。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Thermal Stability Improvement of Cu-Based Catalyst by Hydrophobic Modification in Methanol Synthesis
Water can cause the growth and oxidation of Cu nanoparticles on the surface of Cu-based catalysts, leading to their deactivation. However, during methanol synthesis process from syngas on Cu-based catalysts, water is inevitably produced as a by-product due to the presence of CO2. Therefore, enhancing the stability of Cu-based catalysts during the reaction, particularly in the presence of water, is crucial. In this study, Cu/ZnO/Al2O3 was first subjected to wet etching and then hydrophobically modified using the sol–gel method with methyltrimethoxysilane (MTMS) and the grafting method with 1H,1H,2H,2H-perfluoroalkyltriethoxysilanes (PFOTES) as modifiers. These modifications aimed to mitigate the impact of water on the catalyst and improve its stability. After modification, the catalysts exhibited excellent hydrophobicity and enhanced catalytic activity in the methanol synthesis process. The surface physical properties, composition, and thermal stability of the catalysts before and after hydrophobic modification were characterized by SEM, FT-IR, BET, XRD and TGA. Additionally, molecular dynamics simulations were employed to compare the diffusion behavior of water molecules on the catalyst surfaces before and after hydrophobic modification. The results indicated that the modified catalyst surface formed a micro/nano structure composed of nanosheets and nanosheet clusters, while the hydrophobic modification did not alter the structure of the catalyst. According to the results of simulations, the hydrophobic layers on the modified catalysts were able to expel water quickly from the surfaces and reduce the relative concentration of water molecules at the active sites, thereby improving the stability of the catalyst. Notably, the thermal stability and hydrophobicity of the PFOTES-modified catalyst were superior to those of the MTMS-modified catalyst, resulting in a more significant enhancement in catalyst stability, which aligned with the experimental results.
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来源期刊
Processes
Processes Chemical Engineering-Bioengineering
CiteScore
5.10
自引率
11.40%
发文量
2239
审稿时长
14.11 days
期刊介绍: Processes (ISSN 2227-9717) provides an advanced forum for process related research in chemistry, biology and allied engineering fields. The journal publishes regular research papers, communications, letters, short notes and reviews. Our aim is to encourage researchers to publish their experimental, theoretical and computational results in as much detail as necessary. There is no restriction on paper length or number of figures and tables.
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