Deciphering the Function of NiO Electrocatalyst in Electrooxidation of Alcohols

A study led by Dr Wei Chen, Professor Yuqin Zhou, and Professor Xuanjin Wang (State Key Laboratory of Chemotherapy/Biosensing and Chemometrics, School of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University) reveals the reaction mechanism of a basic alcohol reaction/ Electrodeoxidation reaction of contiguous diols on NiO, particularly for the synergy between electrochemical and non-electrochemical steps.

Electro-oxidation of alcohols on NiO is an indirect electro-oxidation reaction with electrophilic oxygen species as a redox intermediate. Therefore, the electrochemical step is the electrochemical generation of electrophilic oxygen species. The research team found two types of NiO electrocatalytic function mechanisms, that is, the electrophilic oxygen mechanism involving hydrogen atom transfer (EOM-HAT) and the electrophilic oxygen mechanism involving cleavage of the CC bond (EOM-Cleavage of CC bond).

Synergism between EOM-HAT and aldehyde hydration leads to electrooxidation of the primary alcohol (R-CH₂OH) of a carboxylic acid (R-COOH) on NiO. On the other hand, the synergy between EOM-HAT and EOM-Cleavage of the CC bond leads to the electro-oxidation of the neighboring diol (R-CHOH-CH).₂OH) to R-COOH and formic acid (HCOOH) on NiO.

This study was published in the journal National Science Review, highlights the synergy between electrochemical and non-electrochemical steps in the alcohol oxidation reaction. Establishes a unified reaction mechanism for the alcohol redox reaction based on nickel-based electrocatalysts.