Che Qijun, van den Bosch Iris C G, Le Phu T P, Lazemi Masoud, van der Minne Emma, Birkhölzer Yorick A, Nunnenkamp Moritz, Peerlings Matt L J, Safonova Olga V, Nachtegaal Maarten, Koster Gertjan, Baeumer Christoph, de Jongh Petra, de Groot Frank M F
Materials Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, Utrecht 3584 CG, The Netherlands.
MESA+ Institute for Nanotechnology, University of Twente, Enschede 7500 AE, The Netherlands.
J Phys Chem C Nanomater Interfaces. 2024 Mar 20;128(13):5515-5523. doi: 10.1021/acs.jpcc.3c07864. eCollection 2024 Apr 4.
We study the electrocatalytic oxygen evolution reaction using in situ X-ray absorption spectroscopy (XAS) to track the dynamics of the valence state and the covalence of the metal ions of LaFeO and LaFeO/LaNiO thin films. The active materials are 8 unit cells grown epitaxially on 100 nm conductive LaSrMnO layers using pulsed laser deposition (PLD). The perovskite layers are supported on monolayer CaNbO nanosheet-buffered 100 nm SiN membranes. The in situ Fe and Ni K-edges XAS spectra were measured from the backside of the SiN membrane using fluorescence yield detection under electrocatalytic reaction conditions. The XAS spectra show significant spectral changes, which indicate that (1) the metal (co)valencies increase, and (2) the number of 3d electrons remains constant with applied potential. We find that the whole 8 unit cells react to the potential changes, including the buried LaNiO film.
我们使用原位X射线吸收光谱（XAS）研究电催化析氧反应，以追踪LaFeO和LaFeO/LaNiO薄膜中金属离子的价态和共价性的动态变化。活性材料是使用脉冲激光沉积（PLD）在100 nm导电LaSrMnO层上外延生长的8个晶胞。钙钛矿层支撑在单层CaNbO纳米片缓冲的100 nm SiN膜上。在电催化反应条件下，使用荧光产率检测从SiN膜的背面测量原位Fe和Ni K边XAS光谱。XAS光谱显示出显著的光谱变化，这表明：（1）金属（共）价增加；（2）随着施加电位的变化，3d电子数保持不变。我们发现整个8个晶胞对电位变化都有反应，包括埋入的LaNiO薄膜。
