Carbon-Doped Boron Nitride Nanosheet: An Efficient\nMetal-Free Electrocatalyst for the Oxygen Reduction Reaction

Abstract

Replacing precious Pt-based catalysts\nwith cheap and earth-abundant\nmaterials to facilitate the sluggish oxygen reduction reaction (ORR)\nat the cathode is critical to realize the commercialization of fuel\ncells. In this work, we explored the potential of utilizing the experimentally\navailable carbon (C)-doped boron nitride (BN) nanosheet as an ORR\nelectrocatalyst by means of comprehensive density functional theory\n(DFT) computations. Our computations revealed that C-singly doping\ninto <i>h</i>-BN nanosheets can cause high spin density\nand charge density and reduce the energy gap, resulting in the enhancement\nof O₂ adsorption. In particular, the C_N sheet\n(substituting N by C atom) exhibits appropriate chemical reactivity\ntoward O₂ activation and promotes the subsequent ORR steps\nto take place though a four-electron OOH hydrogenation pathway with\nthe largest activation barrier of 0.61 eV, which is lower than that\nof the Pt-based catalyst (0.79 eV). Therefore, the C_N-based\nBN sheet is a promising metal-free ORR catalyst for fuel cells.