3 years ago

Deactivation of a Cobalt Catalyst for Water Reduction through Valence Tautomerism

Deactivation of a Cobalt Catalyst for Water Reduction through Valence Tautomerism
Cláudio N. Verani, Habib Baydoun, Shivnath Mazumder, H. Bernhard Schlegel
The activity of the water reduction catalyst [CoIII(L1)(pyr)2]PF6 (1), where (L1)2− is a bis-amido pyridine ligand and pyr is pyrrolidine, is investigated. Catalyst 1 has an overpotential of 0.54 V and a high observed TOF of 23 min−1, albeit for a relatively short time. Considering the significant activity of 1 and aiming to improve catalyst design, a detailed structural and electronic study is performed to understand the mechanisms of deactivation. Experimental and theoretical evidence support that the metal-reduced [CoI(L1)]− is in tautomeric equilibrium with the ligand-reduced [CoII(L1.)]− species. While [CoI(L1)]− favors formation of a CoIII−H− relevant for catalysis, the [CoII(L1.)]− species leads to ligand protonation, structural distortions, and, ultimatley, catalyst deactivation. Deactivate: A new Co-based water reduction catalyst displays a high TOF of 23 min−1, albeit for a relatively short time. A detailed structural and electronic study was performed to understand the mechanisms of deactivation and conclude that tautomeric equilibrium between [CoI(L1)]− and [CoII(L1.)]− takes place. While the [CoI(L1)]− state supports catalysis through CoIII-H− formation, the [CoII(L1.)]− state leads to catalyst deactivation. This knowledge is instrumental for the future design of robust catalysts.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201701783

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.