Adsorbed-proton promoted oxygen reduction to hydrogen peroxide for enhanced marine ballast water treatment

Abstract

The electrochemical production of hydrogen peroxide through the efficient 2-electron oxygen reduction reaction presents a promising alternative to anthraquinone-based processes for the marine ballast water treatment. However, further exploration is required to develop exceptional electrocatalysts and strategies for modulating their performance. Herein, we present a facile synthetic approach involving simple calcination to prepare amorphous nickel oxide supported on carbon nanotubes. The prepared electrocatalysts exhibit remarkable selectivity (96 % at 0.55 V vs. reversible hydrogen electrode) and high activity. The Faradaic efficiency of hydrogen peroxide reaches 92 % at 0.5 V, and the impressive yield of 1849 mmol⁻¹ g⁻¹h⁻¹ is achieved at 0.1 V. The Ni sites of electrocatalysts play the key role in the adsorption of oxygen gas, while the adsorption of proton on these Ni sites notably promotes the electrocatalytic production of hydrogen peroxide. The in-situ generated hydrogen peroxide demonstrates effective sterilization of ballast water, efficiently inactivating model bacteria such as Escherichia coli and completely eradicating typical marine bacteria.