Earth-abundant manganese oxide nanoneedle as highly efficient electrocatalyst for selective glycerol electro-oxidation to dihydroxyacetone

In this study, earth-abundant manganese oxide (MnO2) was used as a catalyst for the electrocatalytic glycerol oxidation with a satisfactory yield and high selectivity under mild pH media; that is, the high current density of 6.0 mA cm(-2) and selectivity of ca. 46% for dihydroxyacetone (DHA). MnO2 also exhib-ited reasonable durability without considerable changes for 3 h. More importantly, by combination of operando Raman and electrochemical studies, a tentative reaction pathway was also proposed. It is found that high selectivity of formic acid at low potential was due to predominant coverage of alpha-MnO2 on cat-alyst surface. Meanwhile, at high applied potential, partial transformation of alpha-MnO2 to delta-MnO2 causes decreasing C-C bond cleavage, leading to high DHA selectivity. The results of this work not only demon-strate that MnO2 holds promise as an efficient electrocatalyst for selectively producing DHA but also pro-vides realistic details on electrochemically generated species under working condition. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

In this study, earth-abundant manganese oxide (MnO2) was used as an efficient catalyst for the electrocatalytic glycerol oxidation, achieving high yield and selectivity under mild pH conditions. Combining operando Raman and electrochemical studies, a tentative reaction pathway was proposed to explain the high selectivity of formic acid and dihydroxyacetone (DHA) at different applied potentials.