Impact of water adsorbates on the acetaldehyde oxidation reaction on Pt- and Rh-based multimetallic electrocatalysts

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• 作者：Antoine Bach Delpeuch^a ; ^b ; ¹ ; ^{antoine.bachdelpeuch@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Carsten Cremers^a ; Marian Chatenet^b ; ^c ; ²
• 关键词：Acetaldehyde oxidation reaction (AOR) ; CC bond cleavage ; Differential electrochemical mass spectrometry (DEMS) ; Electrocatalysis ; adsorbates
• 刊名：Electrochimica Acta
• 出版年：2016
• 出版时间：10 January 2016
• 年：2016
• 卷：188
• 期：Complete
• 页码：551-559
• 全文大小：2170 K

文摘

The influence of water adsorbates on the acetaldehyde oxidation reaction (AOR) was studied on 20 wt.% Pt/C, Rh/C, Pt-Rh/C and Pt-Rh-SnO₂/C electrocatalysts by means of differential electrochemical mass spectrometry (DEMS) in an electrochemical flow cell. A polyol method was employed to synthesize the home-made electrocatalysts, the physical proprieties of which were analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The investigation by cyclic voltammetry of the AOR was performed after potentiostatic formation of hydrogen- (H_ad) and oxygen-like (OH_ad, O_ad) adsorbates on the electrocatalysts surface at E_ad = 0.05 and 1 V vs. RHE respectively. For comparison, another pre-treatment was achieved at E_ad = 0.3 V vs. RHE, in the double layer region, where neither H⁺ nor OH⁻ adsorption prevails. Comparing the CVs demonstrates that H_ad formation slows down the AOR initiation on Pt/C. The study on Rh/C reveals that water adsorbates are displaced by acetaldehyde species during their adsorption, owing to their stronger polarity. Acetaldehyde adsorption occurs quantitatively at potential as low as E = 0.05 V vs. RHE on Pt-based electrocatalysts. The reaction pathway leading to the formation of CO₂ is promoted during the AOR on Rh-based electrocatalysts (Rh/C, Pt-Rh/C and Pt-Rh-SnO₂/C). The lowest AOR onset potential was recorded on Pt-Rh/C. The present results on the AOR are discussed in the light of a previous similar study on the EOR.