Selective hydrogen peroxide production through water oxidation reaction on Ti/SnO2-Sb-F electrode: Exploring the role of fluorine doping

Abstract

The two-electron water oxidation reaction (WOR) is a promising approach for hydrogen peroxide production, which have many advantages over two-electron oxygen reduction reaction and traditional anthraquinone process. However, the WOR are ordinarily prone to proceed in four-electron path which ends in molecular oxygen production for most water oxidation scenarios. Developing high selective 2 electron WOR catalyst is needed. In this research, a group of fluorine and antimony doped sin dioxide coated titanium electrodes (Ti/SnO₂-Sb-F) were synthesized to study the effect of fluorine doping on hydrogen peroxide production through WOR. The hydrogen peroxide production on Ti/SnO₂-Sb-F-2 can reached 10.34 μmol·cm⁻¹·min⁻¹ with a faradic efficiency of 30.13 % in sodium carbonate electrolyte solution. The production rate was 2.12 times higher than that of Ti/SnO₂-Sb-F-0 without fluorine doping. Electrochemical characterization revealed that fluorine doping improved the conductivity of SnO₂ and resulted in high electrochemical activity for WOR. Theoretical calculation manifested fluorine doping makes WOR more energetically favorable toward hydrogen peroxide production. This paper provides a substantial approach for selection and synthesis of effective catalyst for 2 e⁻ WOR.