Insight into selectivity differences of glycerol electro-oxidation on Pt(111) and Ag(111)

16 November 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Electro-oxidation is a sustainable way to utilize glycerol, a byproduct of biodiesel production, to produce fuels and feedstock chemicals for the chemical industry. A significant challenge is to get products with high selectivity, so it is desirable to understand the glycerol oxidation mechanisms in further details. Using density functional theory calculations, we investigate possible glycerol oxidation intermediates on Pt(111) and Ag(111). We find that the different adsorption preferences of the intermediates on Pt (adsorption via carbon atoms) and on Ag (adsorption via oxygen atoms) lead to different preferred reaction pathways, resulting in different products. The reaction pathways on both surfaces involve glyceraldehyde as a key intermediate, however, upon further oxidation, Pt(111) preferentially produces glyceric acid (CH2OH-CHOH-COOH), while on Ag(111) C-C bonds are broken and leads to production of glycolaldehyde and formic acid (CH2OH-CHO and HCOOH). These predictions agrees well with the experimental outcome of electro-oxidation of glycerol on Pt and Ag surfaces. Our study therefore provides useful insights for optimizing the selectivity of glycerol oxidation and improving the sustainable utilization of glycerol.

Keywords

Glycerol
oxidation
DFT calculations
selectivity
platinum
silver
electrocatalysis

Supplementary materials

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Title
Supporting Information: Insight into selectivity differences of glycerol electro-oxidation on Pt(111) and Ag(111)
Description
List of products and their abbreviations in the glycerol oxidation reaction, productivities and selectivities of experimental glycerol electro-oxidation reactions with different metal catalysts and reaction conditions, lists of all investigated intermediates in the first, second, third, and fourth oxidation step, and NEB reaction pathways for CH2OH-CHOH-*C=O → *CHOH-CHOH-*C=O + H* and CH2OH-CHOH-CH2OH → CH2OH-CHOH-*CHOH + H* on Pt(111).
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Supplementary weblinks

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