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期刊论文 3

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2023 2

关键词

Au/Ti双功能催化剂 1

H₂有效利用率 1

丙烯环氧化 1

密度泛函理论 1

配位不饱和Ti位点 1

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Fabrication of bimetallic Cu–Zn adsorbents with high dispersion by using confined space for gas adsorptive separation

《化学科学与工程前沿（英文）》页码 1623-1631 doi: 10.1007/s11705-022-2202-y

摘要： The number of active components and their dispersion degree are two key factors affecting the performance of adsorbents. Here, we report a simple but efficient strategy for dispersing active components by using a confined space, which is formed by mesoporous silica walls and templates in the as-prepared SBA-15 (AS). Such a confined space does not exist in the conventional support, calcined SBA-15, which does not contain a template. The Cu and Zn precursors were introduced to the confined space in the AS and were converted to CuO and ZnO during calcination, during which the template was also removed. The results show that up to 5 mmol·g^–1 of CuO and ZnO can be well dispersed; however, severe aggregation of both oxides takes place in the sample derived from the calcined SBA-15 with the same loading. Confined space in the AS and the strong interactions caused by the abundant hydroxyl groups are responsible for the dispersion of CuO and ZnO. The bimetallic materials were employed for the adsorptive separation of propene and propane. The samples prepared from the as-prepared SBA-15 showed superior performance to their counterparts from the calcined SBA-15 in terms of both adsorption capacity of propene and selectivity for propene/propane.

关键词： bimetallic adsorbents confined space mesoporous silica propene/propane separation

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The stabilization effect of Al₂O₃ on unconventional Pb/SiO₂ catalyst for propane dehydrogenation

《化学科学与工程前沿（英文）》 2023年第17卷第10期页码 1423-1429 doi: 10.1007/s11705-023-2315-y

摘要： Similar to Sn, Pb located at the same group (IVA) in the periodic table of elements, can also catalyze propane dehydrogenation to propene, while a fast deactivation can be observed. To enhance the stability, the traditional carrier Al₂O₃ with a small amount, was introduced into Pb/SiO₂ catalyst in this study. It has been proved that Al₂O₃ can inhibit the reduction of PbO, and weaken the agglomeration and loss of Pb species due to its enhanced interaction with Pb species. As a result, 3Al15Pb/SiO₂ catalyst exhibits a much higher stability up to more than 150 h. In addition, a simple schematic diagram of the change of surface species on the catalyst surface after Al₂O₃ addition was also proposed.

关键词： Pb/SiO₂ Al₂O₃ propane dehydrogenation propene stability

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配位不饱和Au-O-Ti³⁺活性位点的构建及其在低温丙烯气相环氧化反应中强化氢气效率的研究 Article

宋钊宁, 闫昊, 袁俊聪, 马宏飞, 曹建琳, 王永祥, 王强, 彭冲, 邓风, 冯翔, 陈德, 杨朝合, 胡永康

《工程（英文）》 2023年第25卷第6期页码 144-156 doi: 10.1016/j.eng.2023.01.008

摘要：

自1998年以来，人们广泛认为Au/Ti基催化剂的Au-O-Ti⁴⁺位点是在相对高温条件下丙烯气相环氧化反应的活性位点，但该类催化剂的H₂有效利用率普遍较低。本工作发现了一种在相对低温条件下丙烯气相环氧化反应的新活性位点Au-O-Ti³⁺。值得注意的是，该活性位点主导反应时，最佳温度可从200 °C显著降低至138 °C，并使催化剂保持前所未有的43.6%的H₂有效利用率、90.7%的环氧丙烷（PO）选择性和超过100 h的稳定性。本工作通过调整处理后S-1晶种中Si-OH和Bu₃NH⁺的量，定量构建了Au-O-Ti³⁺活性位点。并且利用原位紫外-可见光谱（operando UV-vis）技术研究了Ti-OOH反应中间体的动态演化过程，结果表明，在Au-O-Ti³⁺活性位点上的Ti-OOH的生成速率比在Au-O-Ti⁴⁺活性位点上的明显增高。此外，氨程序升温脱附（NH₃-TPD）和X射线光电子能谱（XPS）表征以及密度泛函数理论（DFT）计算表明，在相对低温条件下，Au-O-Ti³⁺活性位点中配位不饱和Ti³⁺位点促进了Au和Ti³⁺之间的电子转移，从而增强了催化剂对O₂的吸附能力，有效促进H₂O₂的原位生成，并进一步促进活性中间体Ti-OOH的形成。本工作所报道的结果为强化丙烯直接气相环氧化反应的H₂有效利用率提供了新的思路，而且为低温下丙烯直接气相环氧化反应的工业化推进开辟了新的机会。