Adebayo Busuyi O, Newport Kyle, Yu Han, Rownaghi Ali A, Liang Xinhua, Rezaei Fateme
Department of Chemical & Biochemical Engineering, Missouri University of Science and Technology, 1101 N State Street, Rolla, Missouri 65409, United States.
ACS Appl Mater Interfaces. 2020 Sep 2;12(35):39318-39334. doi: 10.1021/acsami.0c11666. Epub 2020 Aug 19.
This work reports on the development of novel Ni nanoparticle-deposited mixed-metal oxides ZrO-SiO through atomic layer deposition (ALD) method and their application in combined capture and oxidation of benzene, as a model compound of aromatic VOCs. Concentrating ppm-level VOCs in situ, before their oxidation, offers a practical approach to reduce the catalyst inventory and capital cost associated with VOC emissions abatement. The benzene vapor adsorption isotherms were measured at 25 °C and in the pressure range of 0 to benzene saturation vapor pressure thereof (0.13 bar). In the combined capture-reaction tests, the materials were first exposed to ca. 86 100 ppm benzene vapor at 25 °C, followed by desorption and catalytic oxidation while raising the bed temperature to 250 °C. The textural properties revealed that ALD of Ni or ZrO on SiO decreased surface area and pore volume, while sequential doping with ZrO and then Ni caused the otherwise. The benzene vapor adsorption isotherms followed the type-IV isotherm classification, revealing a combination of monolayer-multilayer and capillary condensation adsorption mechanisms in sequence. At saturation vapor pressure, an average equilibrium adsorption capacity of 15 mmol/g was obtained across the materials. However, the dynamic adsorption capacities were up to 50% less than the corresponding equilibrium uptake for the materials. Benzene desorption temperature was observed around 90 °C, and conversion of 85-95% and TOF of 1.28-16.42 mmol/mol/s were obtained over the materials, with 3Ni/ZrO-SiO, prepared with 3 ALD cycles, exhibiting the maximum conversion and TOF indicating synergistic effects of Ni nanoparticles and ZrO support based on the number of ALD cycles. However, the yields of CO and HO were about 5% and 40%, respectively. The small value of the CO yield was hypothesized to be due to simultaneous high-temperature adsorption of CO as the catalytic reaction progressed. The high adsorption affinity, low desorption temperature, and high catalytic activity of the materials investigated in this study made these materials as promising candidates for the abatement of BTX.
这项工作报道了通过原子层沉积（ALD）方法制备新型镍纳米颗粒沉积的混合金属氧化物ZrO-SiO及其在苯（作为芳香族挥发性有机化合物的模型化合物）的联合捕获和氧化中的应用。在氧化之前原位浓缩ppm级挥发性有机化合物，为减少与挥发性有机化合物减排相关的催化剂用量和资本成本提供了一种实用方法。在25℃和0至其苯饱和蒸气压（0.13巴）的压力范围内测量了苯蒸气吸附等温线。在联合捕获-反应测试中，首先将材料在25℃下暴露于约86100 ppm的苯蒸气中，然后进行解吸并在将床层温度升至250℃时进行催化氧化。结构性质表明，在SiO上进行Ni或ZrO的ALD会降低表面积和孔体积，而依次用ZrO和Ni掺杂则会产生相反的效果。苯蒸气吸附等温线遵循IV型等温线分类，依次揭示了单层-多层和毛细管冷凝吸附机制的组合。在饱和蒸气压下，所有材料的平均平衡吸附容量为15 mmol/g。然而，材料的动态吸附容量比相应的平衡吸附量低多达50%。观察到苯的解吸温度约为90℃，材料上的转化率为85-95%，TOF为1.28-16.42 mmol/mol/s，用3个ALD循环制备的3Ni/ZrO-SiO表现出最大转化率和TOF，表明基于ALD循环次数，镍纳米颗粒和ZrO载体具有协同效应。然而，CO和H₂O的产率分别约为5%和40%。CO产率较低被推测是由于催化反应进行时CO同时发生高温吸附。本研究中所研究材料的高吸附亲和力、低解吸温度和高催化活性，使其成为减排苯系物（BTX）的有前途的候选材料。
