Boosting the electron transfer efficiency of Fe3+/Fe2+ cycle in electro-Fenton process using molybdenum: Performance and DFT study

Abstract

Over the last decade, the electro-Fenton (EF) process has been recognized as one of the most popular electrochemical advanced oxidation processes (EAOPs), owing to its outstanding ability to generate highly oxidizing hydroxyl radicals (E°(radical dotOH/H2O) = 2.8 V/SHE), which can non-selectively degrade recalcitrant organic pollutants [1], [2], [3]. A notable feature of the EF process is the continuous in situ production of hydrogen peroxide (H2O2) via two-electron oxygen reduction reaction (1). This enables a continuous flow of radical dotOH generated from Fenton’s reaction (2), which occurs in the presence of added Fe2+ [4], [5]. Furthermore, in EF systems, this ion can be efficiently regenerated via cathodic reduction (reaction (3)), thus enhancing the process sustainability [6]. The effective H2O2 generation and Fe2+ regeneration become pivotal factors to attain high degradation efficiencies in EF [7].