Header

UZH-Logo

Maintenance Infos

Understanding the Dynamics of Molecular Water Oxidation Catalysts with Liquid-Phase Transmission Electron Microscopy: The Case of Vitamin B12


Abdi, Zahra; Balaghi, S Esmael; Sologubenko, Alla S; Willinger, Marc-Georg; Vandichel, Matthias; Shen, Jian-Ren; Allakhverdiev, Suleyman I; Patzke, Greta R; Najafpour, Mohammad Mahdi (2021). Understanding the Dynamics of Molecular Water Oxidation Catalysts with Liquid-Phase Transmission Electron Microscopy: The Case of Vitamin B12. ACS Sustainable Chemistry & Engineering, 9(28):9494-9505.

Abstract

Cobalt compounds are intensely explored as efficient catalysts for the oxygen evolution reaction (OER). Since vitamin B12 is a soluble cobalt compound with high enzymatic activity, evaluating its OER activity is of relevance for biomimetic catalyst research. In this work, the temporal evolution of a homogenous vitamin B12 catalyst in the early stages of OER was investigated by an advanced combination of in situ electrochemical liquid transmission electron microscopy (EC-LTEM), in situ UV–vis spectroelectrochemistry, and extended X-ray absorption fine structure (EXAFS) methods. For the first time, we provided direct evidence of diffuse layer dynamics on the working electrode interface. The results suggested that the formation of cobalt oxyphosphate nanoparticles on the working electrode interface and in the presence of phosphate buffer is the initial stage of the catalytic pathway. Computational results confirmed that the ligand oxidation pathway could occur at potentials below the OER thermodynamic barrier (1.23 V vs reversible hydrogen electrode (RHE)), which leads to a Co ion leaching into the electrolyte. This study showed that investigation of the apparent molecular mechanisms of OER with metal complexes requires careful analyses. We illustrate the high precision and sensitivity of EC-LTEM under operational conditions to monitor heterogeneous catalysts generated during OER and to evaluate their actual roles in the catalytic process.

Abstract

Cobalt compounds are intensely explored as efficient catalysts for the oxygen evolution reaction (OER). Since vitamin B12 is a soluble cobalt compound with high enzymatic activity, evaluating its OER activity is of relevance for biomimetic catalyst research. In this work, the temporal evolution of a homogenous vitamin B12 catalyst in the early stages of OER was investigated by an advanced combination of in situ electrochemical liquid transmission electron microscopy (EC-LTEM), in situ UV–vis spectroelectrochemistry, and extended X-ray absorption fine structure (EXAFS) methods. For the first time, we provided direct evidence of diffuse layer dynamics on the working electrode interface. The results suggested that the formation of cobalt oxyphosphate nanoparticles on the working electrode interface and in the presence of phosphate buffer is the initial stage of the catalytic pathway. Computational results confirmed that the ligand oxidation pathway could occur at potentials below the OER thermodynamic barrier (1.23 V vs reversible hydrogen electrode (RHE)), which leads to a Co ion leaching into the electrolyte. This study showed that investigation of the apparent molecular mechanisms of OER with metal complexes requires careful analyses. We illustrate the high precision and sensitivity of EC-LTEM under operational conditions to monitor heterogeneous catalysts generated during OER and to evaluate their actual roles in the catalytic process.

Statistics

Citations

Dimensions.ai Metrics
17 citations in Web of Science®
18 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

76 downloads since deposited on 14 Feb 2022
23 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
08 Research Priority Programs > Solar Light to Chemical Energy Conversion
Dewey Decimal Classification:540 Chemistry
Scopus Subject Areas:Physical Sciences > General Chemistry
Physical Sciences > Environmental Chemistry
Physical Sciences > General Chemical Engineering
Physical Sciences > Renewable Energy, Sustainability and the Environment
Uncontrolled Keywords:Renewable Energy, Sustainability and the Environment, General Chemical Engineering, Environmental Chemistry, General Chemistry
Language:English
Date:19 July 2021
Deposited On:14 Feb 2022 14:49
Last Modified:27 May 2024 01:53
Publisher:American Chemical Society (ACS)
ISSN:2168-0485
OA Status:Green
Publisher DOI:https://doi.org/10.1021/acssuschemeng.1c03539
Project Information:
  • : FunderSNSF
  • : Grant IDCRSII2_160801
  • : Project TitlePhotocatalytic Processes at Solvated Interfaces
  • Content: Accepted Version