Thermally Stable RuOx-CeO2 Nanofiber Catalysts for Low-Temperature CO Oxidation
Thermally Stable RuOx-CeO2 Nanofiber Catalysts for Low-Temperature CO Oxidation
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DOI：
10.1021/acsanm.0c01815
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发表时间：
2020-08-28
影响因子：
5.9
通讯作者：
Wang, Ruigang
中科院分区：
文献类型：
--
作者：
Liu, Zhongqi;Lu, Yang;Wang, Ruigang
随着人们对可持续能源生产和清洁空气的日益关注，开发高效的催化剂来消除废气排放污染物至关重要。在这项工作中，我们报道了一类热稳定的RuOx-CeO2纳米纤维催化剂，这些催化剂是由简单的一锅静电纺丝法获得的。Ru-CeO2纳米纤维催化剂具有优异的低温活性（150℃以下CO转化率达90%）和长期耐用性。制备的Ru-CeO2纳米纤维催化剂具有较高的比表面积（BET），达到110 m(2)/g，证明了静电纺丝法制备高比表面积催化剂的有效性。Ru-CeO2纳米纤维催化剂具有中空的内部和多孔的外部结构，特别是在Ru-CeO2纳米纤维界面处，提供了大量可接近的CO和氧吸附位点，有利于CO催化氧化。采用H-2程序升温还原法（H-2- tpr）考察了所合成催化剂的还原性。还原后的Ru-CeO2纳米纤维催化剂在室温附近表现出耗氢性能。通过扫描电子显微镜（SEM）、能量色散x射线能谱（EDX）和透射电子显微镜（TEM）对催化剂进行表征，探讨催化剂的微观结构与超低温还原性和CO氧化活性之间的关系。此外，利用x射线光电子能谱（XPS）、co漫反射红外傅立叶变换光谱（DRIFTS）和密度泛函理论（DFT）计算研究了活性表面物质的化学状态，并确定了气体吸附和反应位点。
With the ever-growing concerns for sustainable energy production and clean air, developing highly efficient catalysts to eliminate exhaust emission pollutants is of vital importance. In this work, we report a class of thermally stable RuOx-CeO2 nanofiber catalysts derived from a facile one-pot electrospinning method. Ru-CeO2 nanofiber catalysts exhibit outstanding low-temperature activity (similar to 90% conversion of CO below 150 degrees C) and long-term durability. The as-prepared Ru-CeO2 nanofiber catalysts show a high Brunauer-Emmett-Teller (BET) surface area (>110 m(2)/g), demonstrating the effectiveness of electrospinning for fabricating high-surface-area catalysts. The Ru-CeO2 nanofiber catalysts have a hollow interior and porous exterior structure, particularly at the Ru-CeO2 nanofiber interfaces, providing plentiful accessible CO and oxygen adsorption sites, which are beneficial for CO catalytic oxidation. H-2 temperature-programmed reduction (H-2-TPR) was applied to probe the reducibility of the as-synthesized catalysts. The reduced Ru-CeO2 nanofiber catalysts exhibited hydrogen consumption near room temperature. The catalysts were further characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) to explore the relationship between the microstructure and extraordinary low-temperature reducibility, as well as the CO oxidation activity. In addition, X-ray photoelectron spectroscopy (XPS), in situ CO-diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and density functional theory (DFT) calculation were employed to investigate the chemical states of the active surface species and identify the gas adsorption and reaction sites.