Revisiting the Acetaldehyde Oxidation Reaction on a Pt Electrode by High-Sensitivity and Wide-Frequency Infrared Spectroscopy

Xian-Yin Ma; Chen Ding; Hong Li; Kun Jiang; Sai Duan; Wen-Bin Cai

doi:10.1021/acs.jpclett.0c02558

Revisiting the Acetaldehyde Oxidation Reaction on a Pt Electrode by High-Sensitivity and Wide-Frequency Infrared Spectroscopy

J Phys Chem Lett. 2020 Oct 15;11(20):8727-8734. doi: 10.1021/acs.jpclett.0c02558. Epub 2020 Sep 30.

Authors

Xian-Yin Ma¹, Chen Ding¹, Hong Li¹, Kun Jiang², Sai Duan¹, Wen-Bin Cai¹

Affiliations

¹ Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, Fudan University, Shanghai 200438, China.
² Institute of Fuel Cells, Interdisciplinary Research Center, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.

PMID: 32960060
DOI: 10.1021/acs.jpclett.0c02558

Abstract

High-sensitivity and wide-frequency attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) is highly demanded in unraveling electrocatalytic processes at the molecular level. In this work, an in situ ATR-SEIRAS technique incorporating a micromachined Si wafer window, p-polarized infrared radiation, and isotope labeling is extended to revisit the acetaldehyde oxidation reaction (AOR) on a Pt electrode in an acidic medium. New spectral features in the fingerprint region are detected, including ω(C-H) at 1078 cm^-1 and ν_as(C-C-O) at 919 cm^-1 for adsorbed acetaldehyde and δ(O-C-O) at 689 cm^-1 for adsorbed acetate, besides the other enhanced and clearly discriminated spectral signals at higher frequencies. Time-evolved and potential-dependent ATR-SEIRAS measurements together with advanced density functional theory calculations considering the coadsorption of CO and C₂ species enable clarification of the structures and roles of surface C₂ intermediates (η¹(C)-acetyl and η¹(H)-acetaldehyde), as reflected by the two bands at 1630 and 1663 cm^-1, respectively, leading to updated pathways for the AOR on a Pt electrode.