Construction of 3D Carbon Network with N,B,F-tridoping for Efficient Oxygen Reduction Reaction Electrocatalysis and High Performance Zinc Air Battery

Abstract Nanoarchitecture design and electronic structure engineering are critically important for efficient electrocatalysis. Designing a multi-heteroatoms doped carbon with three dimensional nanoarchitectures can efficiently modulate the electronic structure, create more defective sites and offer a 3D electric conductive circuit, which however has been encountering difficulties in preparation. This work demonstrates the construction of a N,B,F-tridoped 3D carbon network through a novel NH4BF4 triggered self-assembly of chitosan chain. Such a unique structure presents abundant surface active edge defects and in-plane nanopore defects. Density functional theory calculations reveal the significant coupling effect of N,B,F-tridoping down to the atomic scale, whereby the strong electronegativity of F (χ=4.0) can positively charge the carbon matrix and contribute more adjacent carbon active sites. This endows the catalyst with impressive Pt like oxygen reduction reaction (ORR) catalytic performance, with a high onset potential of 0.95V, half-wave potential of 0.818V (vs RHE), and limiting current density of 6.0 mA cm-2. The as constructed zinc-air battery demonstrates a maximum power density of 175 mW cm-2, along with almost unchanged voltage after 25 h galvanostatic discharge.