Che Qijun, Ghiasi Mahnaz, Braglia Luca, Peerlings Matt L J, Mauri Silvia, Torelli Piero, de Jongh Petra, de Groot Frank M F
Materials Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
AREA Science Park, Padriciano 99, I-34149 Trieste, Italy.
ACS Catal. 2024 Jul 12;14(15):11243-11251. doi: 10.1021/acscatal.4c03259. eCollection 2024 Aug 2.
We employed operando soft X-ray absorption spectroscopy (XAS) to monitor the changes in the valence states and spin properties of LaMn Co O catalysts subjected to a mixture of CO and O at ambient pressure. Guided by simulations based on charge transfer multiplet theory, we quantitatively analyze the Mn and Co 2p XAS as well as the oxygen K-edge XAS spectra during the reaction process. The Mn sites are particularly sensitive to the catalytic reaction, displaying dynamics in their oxidation state. When Co doping is introduced ( ≤ 0.5), Mn oxidizes from Mn to Mn and Mn, while Co largely maintains a valence state of Co. In the case of LaCoO, we identify high-spin and low-spin Co species combined with Co. Our investigation underscores the importance to consider the spin and valence states of catalyst materials under operando conditions.
我们采用原位软X射线吸收光谱（XAS）来监测LaMnCoO催化剂在常压下暴露于CO和O混合气体时其价态和自旋性质的变化。在基于电荷转移多重态理论的模拟指导下，我们定量分析了反应过程中的Mn和Co 2p XAS以及氧K边XAS光谱。Mn位点对催化反应特别敏感，其氧化态表现出动态变化。当引入Co掺杂（≤0.5）时，Mn从Mn氧化为Mn和Mn，而Co主要保持Co的价态。在LaCoO的情况下，我们识别出与Co结合的高自旋和低自旋Co物种。我们的研究强调了在原位条件下考虑催化剂材料的自旋和价态的重要性。
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