Lawson Shane, Baamran Khaled, Newport Kyle, Rezaei Fateme, Rownaghi Ali
Department of Chemical & Biochemical Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409-1230, United States.
ACS Appl Mater Interfaces. 2021 Nov 24;13(46):55198-55207. doi: 10.1021/acsami.1c17668. Epub 2021 Nov 10.
Combining CO adsorption and utilization in oxidative dehydrogenation of ethane (ODHE) into a single bed is an exciting way of converting a harmful greenhouse gas into marketable commodity chemicals while reducing energy requirements from two-bed processes. However, novel materials should be developed for this purpose because most adsorbents are incapable of capturing CO at the temperatures required for ODHE reactions. Some progress has been made in this area; however, previously reported dual-functional materials (DFMs) have always been powdered-state composites and no efforts have been made toward forming these materials into practical contactors. In this study, we report the first-generation of structured DFM adsorbent/catalyst monoliths for combined CO capture and ODHE utilization. Specifically, we formulated M-CaO/ZSM-5 monoliths (M = In, Ce, Cr, or Mo oxides) by 3D-printing inks with CaCO (CaO precursor), insoluble metal oxides, and ZSM-5. The physiochemical properties of the monoliths were vigorously characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N physisorption, elemental mapping, pyridine Fourier transform infrared spectroscopy (Py-FTIR), H-temperature-programmed reduction (H-TPR), and NH-temperature-programmed desorption (NH-TPD). Their performances for combined CO adsorption at 600 °C and ODHE reaction at 700 °C under 25 mL/min of 7% CH were then investigated. The combined adsorption/catalysis experiments revealed the best performance in Cr-CaO/ZSM-5, which achieved 56% CO conversion, 91.2% CH selectivity, and 33.8% CH yield. This exceptional performance, which was improved from powdered-state DFMs, was attributed to the high acidity and numerous oxidation states of the CrO dopant which were verified by NH-TPD and H-TPR. Overall, this study reports the first-ever proof-of-concept for 3D-printed DFM adsorbent/catalyst materials and furthers the area of CO capture and ODHE utilization by providing a simple pathway to structure these composites.
将乙烷氧化脱氢（ODHE）过程中的CO吸附与利用整合到单个床层中，是一种将有害温室气体转化为可销售商品化学品的令人兴奋的方式，同时还能降低两床工艺的能源需求。然而，由于大多数吸附剂无法在ODHE反应所需的温度下捕获CO，因此需要开发新型材料。在这一领域已经取得了一些进展；然而，先前报道的双功能材料（DFM）一直是粉末状复合材料，尚未有人致力于将这些材料制成实际的接触器。在本研究中，我们报道了用于CO捕获和ODHE利用相结合的第一代结构化DFM吸附剂/催化剂整体材料。具体而言，我们通过3D打印含有CaCO（CaO前驱体）、不溶性金属氧化物和ZSM-5的油墨来制备M-CaO/ZSM-5整体材料（M = In、Ce、Cr或Mo氧化物）。使用X射线衍射（XRD）、X射线光电子能谱（XPS）、N物理吸附、元素映射、吡啶傅里叶变换红外光谱（Py-FTIR）、H程序升温还原（H-TPR）和NH程序升温脱附（NH-TPD）对整体材料的物理化学性质进行了深入表征。然后研究了它们在600℃下CO吸附和在700℃下ODHE反应（在25 mL/min的7% CH条件下）的性能。吸附/催化联合实验表明Cr-CaO/ZSM-5的性能最佳，实现了56%的CO转化率、91.2%的CH选择性和33.8%的CH产率。这种优于粉末状DFM的卓越性能归因于CrO掺杂剂的高酸度和多种氧化态，这通过NH-TPD和H-TPR得到了验证。总体而言，本研究报道了3D打印DFM吸附剂/催化剂材料的首个概念验证，并通过提供一种构建这些复合材料结构的简单途径，推动了CO捕获和ODHE利用领域的发展。
