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A-site defects in LaSrMnO3 perovskite-based catalyst promoting NO storage and reduction for lean-burn exhausts
Journal of Rare Earths ( IF 5.2 ) Pub Date : 2020-05-01 , DOI: 10.1016/j.jre.2020.04.015
Dongyue Zhao , Yuexi Yang , Zhongnan Gao , Ye Tian , Jing Zhang , Zheng Jiang , Xingang Li

Abstract Herein, we report the high De-NOx performance of the A-site defective perovskite-based Pd/La0.5Sr0.3MnO3 catalyst. The formation of the defective perovskite structure can be proved by both the increased Mn4+/Mn3+ ratio and serious lattice contraction due to cationic nonstoichiometry. It promotes the Sr doping into perovskite lattice and reduces the formation of the SrCO3 phase. Our results demonstrate that below 300 °C the A-site defective perovskite can be more efficiently regenerated than the SrCO3 phase as NOx storage sites due to the latter's stronger basicity, and also exhibits the higher NO oxidation ability than the A-site stoichiometric and excessive catalysts. Both factors promote the low-temperature De-NOx activity of the Pd/La0.5Sr0.3MnO3 catalyst through improving its NOx trapping efficiency. Nevertheless, above 300 °C, the NOx reduction becomes the determinant of the De-NOx activity of the perovskite-based catalysts. A-site defects can weaken the interactions between perovskite and Pd, inducing activation of Pd sites by in-situ transformation from PdO to metallic Pd in the alternative lean-burn/fuel-rich atmospheric alternations, which boosts the De-NOx activity of the Pd/La0.5Sr0.3MnO3 catalyst. The Pd/La0.5Sr0.3MnO3 catalyst exhibits the high sulfur tolerance as well. These findings provide insight into optimizing the structural properties and catalytic activities of the perovskite-based catalysts via tuning formulation, and have potential to be applied for various related catalyst systems.

中文翻译:

LaSrMnO3 钙钛矿基催化剂中的 A 位缺陷促进稀燃废气中 NO 的储存和还原

摘要在此,我们报告了 A 位缺陷钙钛矿基 Pd/La0.5Sr0.3MnO3 催化剂的高脱氮性能。有缺陷的钙钛矿结构的形成可以通过增加的 Mn4+/Mn3+ 比和由于阳离子非化学计量引起的严重晶格收缩来证明。它促进 Sr 掺杂到钙钛矿晶格中并减少 SrCO3 相的形成。我们的结果表明,在 300 °C 以下,由于 SrCO3 相具有更强的碱性,A 位缺陷钙钛矿可以比 SrCO3 相更有效地再生为 NOx 存储位,并且还表现出比 A 位化学计量和过量的 NO 氧化能力更高的氧化能力。催化剂。这两个因素都通过提高其 NOx 捕集效率来促进 Pd/La0.5Sr0.3MnO3 催化剂的低温脱氮活性。然而,在 300 °C 以上,NOx 还原成为钙钛矿基催化剂脱氮活性的决定因素。A 位缺陷可以削弱钙钛矿和 Pd 之间的相互作用,通过在替代的贫燃/富燃料大气交替中从 PdO 原位转化为金属 Pd 来诱导 Pd 位点的活化,从而提高了钙钛矿的脱氮活性。 Pd/La0.5Sr0.3MnO3 催化剂。Pd/La0.5Sr0.3MnO3 催化剂也表现出高硫耐受性。这些发现为通过调整配方优化钙钛矿基催化剂的结构特性和催化活性提供了见解,并有可能应用于各种相关的催化剂体系。在交替的贫燃/富燃料大气交替中,通过从 PdO 到金属 Pd 的原位转化来诱导 Pd 位点的活化,这提高了 Pd/La0.5Sr0.3MnO3 催化剂的脱氮活性。Pd/La0.5Sr0.3MnO3 催化剂也表现出高硫耐受性。这些发现为通过调整配方优化钙钛矿基催化剂的结构特性和催化活性提供了见解,并有可能应用于各种相关的催化剂体系。在交替的贫燃/富燃料大气交替中,通过从 PdO 到金属 Pd 的原位转化来诱导 Pd 位点的活化,这提高了 Pd/La0.5Sr0.3MnO3 催化剂的脱氮活性。Pd/La0.5Sr0.3MnO3 催化剂也表现出高硫耐受性。这些发现为通过调整配方优化钙钛矿基催化剂的结构特性和催化活性提供了见解,并有可能应用于各种相关的催化剂体系。
更新日期:2020-05-01
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