Approach to electrochemical modulating differential extended X‐ray absorption fine structure. (8th June 2022)

• Record Type: Journal Article
• Authors: Xu, Wenjie; Zhang, Guikai; Shou, Hongwei; Zhou, Jia; Chen, Shuangming; Chu, Shengqi; Zhang, Jing; Song, Li
• Is Part Of: Journal of synchrotron radiation. Volume 29:Part 4(2022)
• Page Start: 1065
• Page End: 1073
• Publication Date: 2022-06-08
• Subjects: differential XAS -- modulation excitation spectrum -- phase‐sensitive detection -- electrocatalysis; Synchrotron radiation -- Periodicals; Free electron lasers -- Periodicals; 539.73505
• DOI: 10.1107/S1600577522005616
• Languages: English
• ISSNs: 0909-0495

Abstract

Abstract : The quantitative relationship between phase‐sensitive detection demodulation and difference spectrum is derived and used to quantitatively analyze the electrochemical modulation excitation X‐ray absorption spectrum. Abstract : The differential XAFS technique holds promise for detecting surface changes, which benefits many chemical applications. Phase‐sensitive detection (PSD) analysis based on modulated excitation spectroscopy experiments is expected to obtain a high‐quality difference spectrum, while the mathematical relationship and experiment parameters remain to be discussed. In this article, an approach to obtaining the difference spectrum from the PSD demodulated spectrum is described and its applicability in different experiment settings is discussed. The results indicate that the demodulated spectrum is almost equal to the difference spectrum when the modulating period is 20 times larger than the relaxation time constant. This approach was subsequently applied to an electrochemical modulation experiment and the demodulated spectrum was analyzed. A reversible lattice shrinking is observed via the fitting of demodulated spectra, which is proportional to the charge amount on the electrode. This approach could be used to quantitatively analyze the modulated excitation XAS data and holds promise for a wide range of electrochemical studies.