Waste to treasure: Electrocatalytic upcycling of n-valeraldehyde to octane by Zn-Co bimetallic oxide with atomic level cation defect

Abstract

n-Valeraldehyde is widely used in organic synthesis field as an important intermediate and feedstock, which makes it a significant class of environmental pollutants. In view of the high poisonous and harmful of n-valeraldehyde to human health and ecological environment, it is important to develop green and sustainable technology to reduce the pollution of n-valeraldehyde. In this work, electrocatalytic n-valeraldehyde oxidation using Zn-Co bimetallic oxides was applied to control n-valeraldehyde contamination and highly valuable octane production. To further improve the performance of Zn-Co bimetallic oxides, atomic level Zn vacancies were created across the Zn-Co bimetallic oxides (dx-ZnCo2O4) by post-etching and oxygen vacancy filling methods. Electrochemical experiments results showed that dx-ZnCo2O4 owned a much higher octane yield (1193.4 µmol g−1 h−1) and octane selectivity (octane/butene ≈10). Theoretical calculations demonstrated that the introduction of atomic level Zn vacancies in Zn-Co bimetallic oxide changed the electronic distribution around O, Co and Zn atoms, resulted in an alteration in n-valeraldehyde adsorption sites from Co to Zn, reduced the formation barrier of key intermediate *C4H9 and facilitated the transfer of n-valeraldehyde to octane. This study provides a new idea for the development of high-performance electrocatalysts for controlling n-valeraldehyde pollution.