Oxygen-vacancy mediated acidity and redox properties on WOx/Cu-doped CeO2 for the removal of NOx
Oxygen-vacancy mediated acidity and redox properties on WOx/Cu-doped CeO2 for the removal of NOx
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DOI：
10.1016/j.jece.2021.106024
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发表时间：
2021-10
影响因子：
7.7
通讯作者：
Zhifei Hao;Guoquan Liu;Nan Ma;He Zhang;Yi Li;Yuguo Xia;Dongpeng Zhang;Sihui Zhan
中科院分区：
文献类型：
--
作者：
Zhifei Hao;Guoquan Liu;Nan Ma;He Zhang;Yi Li;Yuguo Xia;Dongpeng Zhang;Sihui Zhan
催化剂的酸性和氧化还原性能是影响NH3-SCR性能的两个关键因素。在此，我们设计了一种新型WOx/Cu-CeO2氧化物催化剂，其中WOx物种高度分散在Cu掺杂CeO2纳米球的{111}/{100}端接表面上，该催化剂表现出巨大的脱硝活性优势和宽工作温度范围（200–400°C，超过85%的NOx转化率，气时空速（GHSV）为60,000 h−1)，以及良好的抗硫性和 N2 选择性。在NH3-SCR反应中建立了WOx/Cu-CeO2催化剂的组成、酸度和氧化还原性质之间的关系。综合实验研究和光谱表征表明，在CeO2晶格中引入Cu不仅增加了表面Ce3+和氧空位浓度，而且还为WOx物种的捕获和分散提供了更多的位点，从而介导和改善了路易斯和布朗斯台德酸位点以及催化剂的还原性。 XPS和DFT计算进一步表明，由于短程Ce-O-Cu和Ce-O-W相互作用的存在，WOx与Cu掺杂CeO2之间的电子相互作用增强。此外，根据原位DRIFTS，WOx/Cu-CeO2上的NH3-SCR反应可能遵循Langmuir-Hinshelwood和Eley-Rideal反应路径。
Acidity and redox properties of the catalyst are two crucial factors affecting the performance of NH3-SCR. Herein, we design a novel WOx/Cu-CeO2oxide catalyst in which the WOxspecies are highly dispersed on the {111}/{100}-terminated surface of Cu-doped CeO2nanospheres, which exhibits great deNOxactivity advantage and wide operating temperature window (200–400 °C, over 85% NOxconversion with a gas hourly space velocity (GHSV) of 60,000 h−1), as well as good sulfur resistance and N2selectivity. The relationship among the composition, acidity and redox properties of the WOx/Cu-CeO2catalyst is established in the NH3-SCR reaction. The combined experimental studies and spectroscopic characterization reveal that the introduction of Cu into the lattice of CeO2not only increases the surface Ce3+and oxygen vacancy concentration but also provides more sites for capture and dispersion of WOxspecies, thus mediating and improving the Lewis and Brønsted acid sites and reducibility of catalyst. XPS and DFT calculations further demonstrate that electronic interaction between WOxand Cu-doped CeO2is enhanced duo to the existence of interactions of short-range Ce-O-Cu and Ce-O-W. Moreover, the NH3-SCR reaction over WOx/Cu-CeO2may follow both Langmuir-Hinshelwood and Eley-Rideal reaction pathway according to thein situDRIFTS.