# Incorporation of Ion Transport Chains into Multivariate MOF for Improved Water Oxidation

## TL;DR

This paper describes a new method to improve water oxidation catalysts by embedding them in a special material called a MOF with proton transfer pathways.

## Contribution

The novel contribution is the integration of proton transfer pathways into MOFs to enhance water oxidation catalysis.

## Key findings

- Sulfonated MOFs showed a 2.5-fold increase in oxygen evolution compared to nonsulfonated MOFs.
- The sulfonated MOF achieved a turnover number of 25 after 1 hour of electrolysis, versus 10 for the native MOF.

## Abstract

The climate crisis demands clean energy technologies
to cut CO2 emissions from fossil fuels. Hydrogen fuel cells
and solar-driven
CO2 reduction are promising, but both rely on efficient
water oxidation. Polypyridyl ruthenium complexes are active catalysts
for water oxidation; however, they exhibit poor stability and recyclability.
Our group improved performance by embedding these complexes into metal–organic
frameworks (MOFs). As water oxidation is pH-dependent, proton management
further enhances reactivity. To address the issue, we introduced proton
transfer pathways into the MOF structure. Specifically, we incorporated
−SO3H groups onto the biphenyl linkers of UiO-67
loaded with [Ru­(tpy)­(dcbpy)­OH2]­PF6 catalyst
(where tpy = 2,2′:6′,2″-terpyridine; dcbpy =
5,5-dicarboxy-2,2′-bipyridine). The sulfonated MOF exhibited
a 2.5-fold increase in oxygen evolution compared to the nonsulfonated
analogue. After 1 h of electrolysis, the sulfonated MOF exhibited
a turnover number of 25 for oxygen evolution reaction compared to
10 for the native MOF, demonstrating the benefits of built-in proton
management.