Noble-Metal-Free Electrocatalysts for Selective Hydrogen Peroxide Generation via Oxygen Reduction Reaction

Hydrogen peroxide (H₂O₂) is a versatile chemical widely used in various industries. The traditional anthraquinone method for H₂O₂ synthesis has environmental and safety concerns due to the use of organic solvents and hazardous by-products. The direct synthesis of H₂O₂ from H₂ and O₂ poses risks of flammability and explosion. Recently, the 2-electron oxygen reduction reaction (2e^- ORR) method has emerged as a promising alternative, offering safety, environmental friendliness, and cost-effectiveness. This method utilizes gas diffusion electrodes to efficiently generate H₂O₂ without the need for additional dilution. In this review, we focus on the recent advancements in noble-metal-free materials for 2e^- ORR electrocatalysis, which play a crucial role in the efficient production of H₂O₂. These materials, including transition metal compounds, macrocyclic complexes, carbon-based catalysts, framework materials, and MXenes catalysts, demonstrate significant advantages in enhancing H₂O₂ yield. The development of these non-precious metal catalysts can reduce costs and improve sustainability and promote the commercialization of related technologies. The review concludes with an outlook on the future trends of 2e^- ORR electrocatalysts.