氧还原反应中四电子和两电子的研究进展

Oxygen reduction reaction (ORR) is the core electrochemical process of clean energy technologies such as fuel cells and metal-air batteries, and the performance of its catalyst directly affects the energy conversion efficiency and device life. In this paper, we systematically review the research progress of catalysts with four electrons (complete reduction to H?O) and two electrons (selective generation of H?O?), focusing on the advantages, challenges and future development directions of precious and non-precious metal systems. Among the four-electron ORR catalytic systems, the precious metal platinum (Pt) remains the performance benchmark of commercial catalysts due to its moderate oxygen intermediate adsorption energy and high charge transfer efficiency. However, the resource scarcity and overpotential limitation of platinum-based materials have prompted researchers to focus on alloying strategies and nanostructure design. At the same time, non-precious metal catalysts show substitution potential. Cobalt-based spinel oxides induce electron synergy through the crystal field effect, approaching the activity of platinum in alkaline media. However, non-precious metal systems face severe challenges in a strongly acidic environment. To overcome these bottlenecks, it is necessary to strengthen the intrinsic stability of materials through defect engineering, carrier composite, and surface passivation. The two-electron ORR pathway has attracted much attention for the in-situ synthesis of hydrogen peroxide (H?O?), the core of which is to precisely control the adsorption intensity and O-O bond activation degree of the catalyst to *OOH intermediates. Precious metal-based materials achieve a balance of high selectivity and activity through surface engineering and heterostructure design. Due to its multi-level pore structure and tunable electronic properties, the non-noble metal system exhibits good H?O? selectivity in alkaline media, but the problems of corrosion deactivation and active site reconstruction under acidic conditions need to be solved urgently.