A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Mechanistic Origins of the pH Dependency in Au-Catalyzed Glycerol Electro-oxidation : Insight from First-Principles Calculations (2022)

Verma, A. M., Laverdure, L., Melander, M. M., & Honkala, K. (2022). Mechanistic Origins of the pH Dependency in Au-Catalyzed Glycerol Electro-oxidation : Insight from First-Principles Calculations. ACS Catalysis, 12(1), 662-675. https://doi.org/10.1021/acscatal.1c03788

JYU-tekijät tai -toimittajat

Verma, Anand
Laverdure, Laura
Melander, Marko
Honkala, Karoliina

Julkaisun tiedot

Julkaisun kaikki tekijät tai toimittajat: Verma, Anand M.; Laverdure, Laura; Melander, Marko M.; Honkala, Karoliina

Lehti tai sarja: ACS Catalysis

eISSN: 2155-5435

Julkaisuvuosi: 2022

Ilmestymispäivä: 24.12.2021

Volyymi: 12

Lehden numero: 1

Artikkelin sivunumerot: 662-675

Kustantaja: American Chemical Society (ACS)

Julkaisumaa: Yhdysvallat (USA)

Julkaisun kieli: englanti

DOI: https://doi.org/10.1021/acscatal.1c03788

Julkaisun avoin saatavuus: Avoimesti saatavilla

Julkaisukanavan avoin saatavuus: Osittain avoin julkaisukanava

Julkaisu on rinnakkaistallennettu (JYX): https://jyx.jyu.fi/handle/123456789/79190

Tiivistelmä

Electrocatalytic oxidation of glycerol (EOG) is an attractive approach to convert surplus glycerol to value-added products. Experiments have shown that EOG activity and selectivity depend not only on the electrocatalyst but also on the electrode potential, the pH, and the electrolyte. For broadly employed gold (Au) electrocatalysts, experiments have demonstrated high EOG activity under alkaline conditions with glyceric acid as a primary product, whereas under acidic and neutral conditions Au is almost inactive producing only small amounts of dihydroxyacetone. In the present computational work, we have performed an extensive mechanistic study to understand the pH and potential dependency of Au-catalyzed EOG. Our results show that activity and selectivity are controlled by the presence of surface-bound hydroxyl groups. Under alkaline conditions and close to the experimental onset potential, modest OH coverage is preferred according to our constant potential calculations. This indicates that both Au(OH)ads and Au can be active sites and they cooperatively facilitate the thermodynamically and kinetically feasible formation of glyceric acid thus explaining the experimentally observed high activity and selectivity. Under acidic conditions, hydroxide coverage is negligible and the dihydroxyacetone emerges as the favored product. Calculations predict slow reaction kinetics, however, which explains the low activity and selectivity toward dihydroxyacetone reported in experiments. Overall, our findings highlight that computational studies should explicitly account for pH and coverage effects under alkaline conditions for electrocatalytic oxidation reactions to reliably predict electrocatalytic behavior.

YSO-asiasanat: orgaaninen kemia; hapetus; katalyysi; elektrolyytit

Vapaat asiasanat: glyseroli

Tieteenalat: