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Structural selectivity of supported Pd nanoparticles for catalytic NH 3 oxidation resolved using combined operando spectroscopy
Nature Catalysis ( IF 42.8 ) Pub Date : 2019-01-28 , DOI: 10.1038/s41929-018-0213-3
Ellie K. Dann , Emma K. Gibson , Rachel H. Blackmore , C. Richard A. Catlow , Paul Collier , Arunabhiram Chutia , Tugce Eralp Erden , Christopher Hardacre , Anna Kroner , Maarten Nachtegaal , Agnes Raj , Scott M. Rogers , S. F. Rebecca Taylor , Paul Thompson , George F. Tierney , Constantinos D. Zeinalipour-Yazdi , Alexandre Goguet , Peter P. Wells

The selective catalytic oxidation of NH3 to N2 presents a promising solution for the abatement of unused NH3-based reductants from diesel exhaust after treatment. Supported Pd nanoparticle catalysts show selectivity to N2 rather than NOx, which is investigated in this work. The link between Pd nanoparticle structure and surface reactivity was found using operando X-ray absorption fine structure spectroscopy, diffuse reflectance infrared Fourier-transformed spectroscopy and on-line mass spectrometry. Nitrogen insertion into the metallic Pd nanoparticle structure at low temperatures (<200 °C) was found to be responsible for high N2 selectivity, whereas the unfavourable formation of NO is linked to adsorbed nitrates, which form at the surface of bulk PdO nanoparticles at high temperatures (>280 °C). Our work demonstrates the ability of combined operando spectroscopy and density functional theory calculations to characterize a previously unidentified PdNx species, and clarify the selectivity-directing structure of supported Pd catalysts for the selective catalytic oxidation of NH3 to N2.



中文翻译:

组合操作光谱法解析负载的Pd纳米颗粒对NH 3催化氧化的结构选择性

NH 3选择性催化氧化为N 2提出了一种有希望的解决方案,用于处理后从柴油机废气中减少未使用的NH 3基还原剂。负载的Pd纳米颗粒催化剂显示出对N 2的选择性,而不是NO x的选择性,这是在这项工作中进行的。使用操作X射线吸收精细结构光谱,漫反射红外傅里叶变换光谱和在线质谱法发现了Pd纳米颗粒结构与表面反应性之间的联系。发现氮在低温(<200°C)下插入金属Pd纳米颗粒结构中是造成高N 2的原因选择性,而NO的不利形成与吸附的硝酸盐有关,硝酸盐在高温(> 280°C)时在大量PdO纳米颗粒的表面形成。我们的工作证明了结合操作光谱和密度泛函理论计算来表征先前未鉴定的PdN x物种的能力,并阐明了负载型Pd催化剂对NH 3选择性催化氧化为N 2的选择性-导向结构。

更新日期:2019-01-29
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