Header

UZH-Logo

Maintenance Infos

Exploring the Limitation of Molecular Water Oxidation Catalysts


Busch, Michael; Fabrizio, Alberto; Luber, Sandra; Hutter, Jürg; Corminboeuf, Clemence (2018). Exploring the Limitation of Molecular Water Oxidation Catalysts. Journal of Physical Chemistry C, 122(23):12404-12412.

Abstract

Linear free energy scaling relationships (LFESRs) and volcano plots are routinely used to assess the performance of heterogeneous electrocatalysts and have only recently been concretely exploited in homogeneous catalysis. These tools efficiently compare and provide a global evaluation of catalyst performance while highlighting the limitations for a given reaction. In the framework of solid-state water oxidation, a minimal overpotential of 0.4 eV has been predicted on the basis of LFESRs. Considering the very different nature of homogeneous catalysts compared to solid-state systems, the validity of scaling relationships determined for the former cannot be assumed. To evaluate the global limitations of molecular O-2 evolution catalysts, LFESRs are established for all key intermediates for different metal (Mn, Co, Ru, Rh, Ir) and ligand (corrole and perfluoro-porphyrin) combinations assuming a mononuclear mechanism that proceeds through *=OH, *=O, and *-OOH intermediates. Our computations indicate that the LFESRs strongly depend on the choice of density functional. Using GMC-QDPT2 as a benchmark, strong scaling relationships between all intermediates are observed, but the relationships between *-OH and *=O significantly differ from those found in solid-state systems. Consequently, the shape of the molecular volcano plot changes drastically from its solid-state counterpart and shows a broad plateau at the top where the overpotential is nearly independent of the choice of catalyst. This plateau renders the performance of molecular catalysts extremely robust, but inhibits improvements by proceeding through alternative reaction mechanisms.

Abstract

Linear free energy scaling relationships (LFESRs) and volcano plots are routinely used to assess the performance of heterogeneous electrocatalysts and have only recently been concretely exploited in homogeneous catalysis. These tools efficiently compare and provide a global evaluation of catalyst performance while highlighting the limitations for a given reaction. In the framework of solid-state water oxidation, a minimal overpotential of 0.4 eV has been predicted on the basis of LFESRs. Considering the very different nature of homogeneous catalysts compared to solid-state systems, the validity of scaling relationships determined for the former cannot be assumed. To evaluate the global limitations of molecular O-2 evolution catalysts, LFESRs are established for all key intermediates for different metal (Mn, Co, Ru, Rh, Ir) and ligand (corrole and perfluoro-porphyrin) combinations assuming a mononuclear mechanism that proceeds through *=OH, *=O, and *-OOH intermediates. Our computations indicate that the LFESRs strongly depend on the choice of density functional. Using GMC-QDPT2 as a benchmark, strong scaling relationships between all intermediates are observed, but the relationships between *-OH and *=O significantly differ from those found in solid-state systems. Consequently, the shape of the molecular volcano plot changes drastically from its solid-state counterpart and shows a broad plateau at the top where the overpotential is nearly independent of the choice of catalyst. This plateau renders the performance of molecular catalysts extremely robust, but inhibits improvements by proceeding through alternative reaction mechanisms.

Statistics

Citations

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

Altmetrics

Downloads

1 download since deposited on 14 Feb 2019
0 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Uncontrolled Keywords:General Energy, Physical and Theoretical Chemistry, Electronic, Optical and Magnetic Materials, Surfaces, Coatings and Films
Language:English
Date:14 June 2018
Deposited On:14 Feb 2019 14:43
Last Modified:29 Sep 2019 05:56
Publisher:American Chemical Society (ACS)
ISSN:1932-7447
OA Status:Closed
Publisher DOI:https://doi.org/10.1021/acs.jpcc.8b03935
Project Information:
  • : FunderNational Centre of Competence in Research (NCCR) of the Swiss National Science Foundation (SNSF)
  • : Grant ID
  • : Project TitleMaterials' Revolution: Computational Design and Discovery of Novel Materials (MARVEL)
  • : FunderEPFL
  • : Grant ID
  • : Project Title

Download

Closed Access: Download allowed only for UZH members