Activation of molecular oxygen over Mn-doped La2CuO4 perovskite for direct epoxidation of propylene,Catalysis Science & Technology

当前位置： X-MOL 学术 › Catal. Sci. Technol. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Activation of molecular oxygen over Mn-doped La2CuO4 perovskite for direct epoxidation of propylene
Catalysis Science & Technology ( IF 4.4 ) Pub Date : 2022-02-08 , DOI: 10.1039/d1cy02185k
Xinxin Zhang ₁ , Jiajun Dai ₁ , Jiageng Ding ₁ , Kok Bing Tan ₁ , Guowu Zhan ₂ , Jiale Huang ₁ , Qingbiao Li _{1,

3}

Affiliation

Direct epoxidation of propylene (DEP) to propylene oxide (PO) with molecular oxygen is a very desirable reaction but remains a challenge due to the absence of efficient catalysts with high selectivity. The catalytic performance for direct epoxidation of propylene is well related to surface adsorbed electrophilic oxygen species. Herein, we prepared a series of Mn-doped La₂CuO₄ perovskites (LaMn_xCu_1−xO₃) with adjustable valence electronic structure as selective catalysts to explore the impacts of catalyst intrinsic electronic structure evolution on the activation of molecular oxygen. Therein, LaMn_0.5Cu_0.5O₃ performed the best with a PO selectivity of 74.2% at 150 °C. The characterization results and DFT calculations revealed that the excellent catalytic performance of LaMn_0.5Cu_0.5O₃ might be ascribed to the change of molecular oxygen activation sites: from oxygen vacancy active sites on La₂CuO₄ to Cu active sites on LaMn_0.5Cu_0.5O₃. Meanwhile, there was a synergistic interaction between manganese and copper affecting the electron density on Cu sites and ultimately modulating the activated states of surface adsorbed oxygen species. In addition, we employed crystal band theory to associate the oxygen vacancy density with the Cu valence state. This is important for people to understand the bulk electronic structure evolution rules caused by transition metal doping and to design catalysts efficiently for oxygen-based chemical reactions.

中文翻译：

Mn掺杂La2CuO4钙钛矿上的分子氧活化用于丙烯的直接环氧化

用分子氧将丙烯 (DEP) 直接环氧化成环氧丙烷 (PO) 是一种非常理想的反应，但由于缺乏具有高选择性的高效催化剂，仍然是一个挑战。丙烯直接环氧化的催化性能与表面吸附的亲电氧物种密切相关。在此，我们制备了一系列具有可调价电子结构的Mn掺杂的La ₂ CuO ₄钙钛矿（LaMn _x Cu _{1− x} O ₃）作为选择性催化剂，以探索催化剂本征电子结构演化对分子氧活化的影响。其中，LaMn _0.5 Cu _0.5 O ₃在 150 °C 时 PO 选择性为 74.2%，表现最佳。表征结果和DFT计算表明，LaMn _0.5 Cu _0.5 O ₃优异的催化性能可能归因于分子氧活性位点的变化：从La ₂ CuO ₄上的氧空位活性位点到LaMn _0.5 Cu _0.5上的Cu活性位点氧₃. 同时，锰和铜之间存在协同相互作用，影响铜位点上的电子密度，最终调节表面吸附氧的活化状态。此外，我们采用晶带理论将氧空位密度与Cu价态联系起来。这对于人们了解过渡金属掺杂引起的体电子结构演化规律以及高效设计用于氧基化学反应的催化剂具有重要意义。

更新日期：2022-02-08

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南