A bio-inspired coordination polymer as outstanding water oxidation catalyst via second coordination sphere engineering.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31699987.
- Also identified by DOI 10.1038/s41467-019-13052-1 and PMC identifier 6838099.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
First-row transition metal-based catalysts have been developed for the oxygen evolution reaction (OER) during the past years, however, such catalysts typically operate at overpotentials (η) significantly above thermodynamic requirements. Here, we report an iron/nickel terephthalate coordination polymer on nickel form (NiFeCP/NF) as catalyst for OER, in which both coordinated and uncoordinated carboxylates were maintained after electrolysis. NiFeCP/NF exhibits outstanding electro-catalytic OER activity with a low overpotential of 188 mV at 10 mA cm<sup>-2</sup> in 1.0 KOH, with a small Tafel slope and excellent stability. The pH-independent OER activity of NiFeCP/NF on the reversible hydrogen electrode scale suggests that a concerted proton-coupled electron transfer (c-PET) process is the rate-determining step (RDS) during water oxidation. Deuterium kinetic isotope effects, proton inventory studies and atom-proton-transfer measurements indicate that the uncoordinated carboxylates are serving as the proton transfer relays, with a similar function as amino acid residues in photosystem II (PSII), accelerating the proton-transfer rate.