Modification of Nanodiamond and Its Application in Electrocatalytic Oxygen Reduction Reaction

Oxygen reduction reaction (ORR) is an important cathodic reaction, but its slow reaction kinetics seriously hinders the application of clean energy devices such as fuel cells and metal-air batteries. Although platinum (Pt)-based catalysts possess excellent ORR activity, their high cost, scarce reserves, poor stability and tolerance make it difficult to commercialize current clean energy technologies. To address the above problems, it is urgent to develop new types of efficient and low-cost ORR catalysts. As an emerging carbon-based material, nanodiamond (ND) exhibits broad application prospects in ORR catalysis due to its advantages such as low cost, controllable functional group modification, high surface energy (>1000 mJ·m-2), and unique π and σ bond configurations. This paper reviews the latest research progress of ND catalysts. Firstly, preparation methods such as detonation, chemical vapor deposition, pulsed laser ablation, and high-pressure high-temperature are introduced. Subsequently, modification strategies including heteroatom doping, surface functionalization, material composite, and morphology regulation are summarized, and their formation mechanism of active centers and regulation rules of reaction paths are analyzed, covering influence of different modification strategies on catalytic performance and comparison of relevant performance data. Finally, the challenges faced by current ND catalysts in catalytic mechanism, synthesis process, characterization technology, and design methods are analyzed to suggest the future development directions for the research and development of new carbon-based ORR catalysts.