Electrocatalytic Oxygen Reduction to Hydrogen Peroxide: From Homogenous to Heterogenous Electrocatalysis

Hydrogen peroxide (H2O2) is an environmentally friendly oxidant, finding widespread use across the chemical industry, in sanitation and environmental remediation. Currently, H2O2 is manufactured via the anthraquinone process which has a number of disadvantages including nondistributed production, high-energy consumption, substantial organic by-product waste, and the need to transport the obtained H2O2 to the point-of-use. Accordingly, the electrochemical synthesis of H2O2 is now attracting a lot of interest as an alternative, cost-effective, small-scale, and distributed technology for H2O2 manufacture. This review summarizes recent advancements in the development of homogenous and heterogenous catalysts for electrocatalytic O-2 reduction reaction (ORR) to H2O2. The basic principles of the ORR, and methodologies for investigating the ORR to H2O2 are first introduced. Next, H2O2 production over homogenous catalysts is discussed, with a focus on the reaction mechanisms and the factors that influence activity, selectivity, and reaction kinetics. Subsequently, recent breakthroughs in H2O2 synthesis over heterogenous catalysts, including nonnoble metal-based nanomaterials, carbon materials, and single-atom catalysts are described. The latter are given special attention, since they serve as a bridge between homogenous catalysis and heterogenous catalysis, while also offering excellent performance. Finally, the challenges and opportunities for electrochemical ORR to H2O2 are critically discussed.

Automated summary

This review highlights the recent advancements in homogenous and heterogenous catalysts for electrocatalytic O-2 reduction reaction (ORR) to H2O2, covering the basic principles of ORR and methodology for investigating ORR to H2O2. It discusses H2O2 production over homogenous catalysts and recent breakthroughs with heterogenous catalysts, emphasizing nonnoble metal-based nanomaterials, carbon materials, and single-atom catalysts. Challenges and opportunities for electrochemical ORR to H2O2 are also critically examined in the review.