Tran GS, Vo TG, Chiang CY.
Operando Revealing the Crystal Phase Transformation and Electrocatalytic Activity Correlation of MnO
2 toward Glycerol Electrooxidation.
ACS APPLIED MATERIALS & INTERFACES 2023;
15:22662-22671. [PMID:
37096961 DOI:
10.1021/acsami.3c00857]
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Abstract
In this work, we report for the first time a comprehensive operando investigation of the intricate correlation between dynamic phase evolution and glycerol electrooxidation reaction (GEOR) performance across three primary MnO2 crystallographic phases (α-, β-, and γ-MnO2). The results showed that all three electrocatalysts exhibited comparable selectivity toward three-carbon products (∼90%), but γ-MnO2 exhibited superior performance, with a low onset potential of ∼1.45 VRHE, the highest current density of ∼1.9 mA cm-2 at 1.85 VRHE, and reasonable stability. Operando Raman spectroscopy revealed the potential-induced surface reconstruction of different MnO2 structures from which a correlation among the applied potential, electrocatalytic activity, and product distribution was identified. The higher the applied potential, the greater conversion from the original structure to δ-MnO2, resulting in lower C-C cleavage and higher 3C product selectivity. This study not only provides a systematic understanding of structure-controlled electrocatalytic activity for high selectivity toward 3C products of MnO2 but also contributes to the development of a non-noble and environmentally friendly catalyst for valorizing glycerol.
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