Metal-Free Electrocatalyst for Water Oxidation Initiated by Hydrogen Atom Transfer

Abstract

Direct activation of O−H bond in water via hydrogen atom transfer (HAT) reactions is a challenge because of its high bond dissociation energy. In this work, a strong hydrogen atom abstracting reagent (pyridine-N-oxyl radical cation: Py + -O • ) was generated by an electrochemical method, and this intermediate could trigger catalytic water oxidation via a two-electron pathway to H 2 O 2 under metal-free conditions.

Hydrogen spillover in complex oxide multifunctional sites improves acidic hydrogen evolution electrocatalysis

“…Furthermore, H/D kinetic isotope effects (KIEs) can reflect the hydrogen or proton transfer kinetic information of chemical reactions, and the presence of KIEs (KIEs > 1.5) is considered as evidence that proton or hydrogen transfer is involved to affect the reaction rate 60 – 63 . The KIEs experiment in 0.5 M D 2 SO 4 /D 2 O solution was performed to obtain insight into the role of hydrogen transfer during the HER.…”

Small Organic Molecule Based on Benzothiadiazole for Electrocatalytic Hydrogen Production

“… 4 , 5 While often being utilized as ligands in metal complexes or building blocks in organic materials, small organic molecules have not been well studied as catalysts for these types of redox reactions. Recently, small, aromatic, and nitrogen-rich organic compounds have been demonstrated to facilitate both water oxidation 6 , 7 and CO 2 reduction. 8 − 12 When it comes to hydrogen evolution, there are very few reported cases that we know of.…”

Visible-light driven water oxidation and oxygen production at soft interfaces

“…5 Li et al reported the use of pyridine-N-oxyl radical cation (Py + -O ) acting as catalyst for WOR, where Py + -O catalyses water activation via the stepwise two-electron/two-proton pathway to give H 2 O 2 . 6 7,7,8,8-Tetracyanoquinodimethane, TCNQ, and their halogenated derivates can be reduced to form the anion radical and the dianion, hence these species can act as strong organic electron acceptors, with a high electron affinity of 2.8 eV. 7 For example, conductive electrodes based on Fe 2+ (TCNQ À ) 2 nanorod arrays adsorbed on a copper foam, can perform the WOR at overpotentials of 0.32 and 0.35 V at 20 and 50 mA cm À2 respectively, in strong basic media.…”