Production of Hydrogen Peroxide Using Various Metal-Based Catalysts in Electrochemical and Bioelectrochemical Systems: Mini Review

Abstract

Catalysts play an essential role in various electrochemical reactions followed during the synthesis of hydrogen peroxide (H2O2). Plenty of investigations on the role of catalysts in the synthesis of H2O2 have been made in recent times. In this regard, palladium (Pd) is the most favored catalyst used by the researchers for the production of H2O2; however, monometallic Pd catalysts hydrogenate H2O2 if no acids or halide stabilizers are used. Nowadays, direct synthesis of H2O2 is mainly furnished by active metal-based catalysts such as gold, palladium, nickel, platinum, iron, silver, or manganese. However, the alloys of Au-Pd/C, Ni-Pd/C, and Au-Pd/TiO2 are also being encouraged because of their increased electrochemical activity. The efficacy of H2O2 production is highly dependent upon the type of cathode catalyst used and the pH of the solution. The electro-Fenton process, which uses Fenton reagents (dissolved Fe+2 and H2O2) to produce hydroxyl ions, is also an effective method for the degradation of biorefractory organic pollutants present in wastewater. This novel process can be made feasible if H2O2 can be produced in situ. In situ H2O2 production can be particularly important and attractive for tertiary treatment of sewage and for the removal of emerging contaminants. Thus, this mini review focuses on the effectiveness of various metal-based catalysts and the application of bioelectrochemical systems for the synthesis of H2O2.