Biphenylene with doping B/N as promising metal-free single-atom catalysts for electrochemical oxygen reduction reaction.

The oxygen reduction reaction (ORR) is the key bottleneck in the performance of fuel cells. The rational design of efficient and inexpensive ORR electrocatalysts is a common goal for the large-scale application of fuel cells. Herein, by means of density functional theory calculations, we demonstrate that two-dimensional (2D) biphenylene (BPN) with doping B/N are metal-free single-atom catalyst candidates with the overpotentials comparable to those noble metal benchmark catalysts. The B/N doping effectively modulates the charge distribution in BPN sheets, promotes the electron transfer between doped BPN and the oxygen-containing intermediates, which results in enhancing their binding strength, and facilitating their electrochemical ORR catalytic activity. This work not only provides metal-free single-atom catalysts for ORR, but also promotes BPN nanomaterials for single-atom catalysts development and practical applications. [Display omitted] • 2D biphenylene with doping B/N are metal-free single-atom catalysts. • N 2 -BPN exhibits superior ORR performance with a overpotential of 0.40 V. • N substituting C 2 atom in BPN could tune charge redistribution of active C 1 atom. • N 2 -BPN exhibits a suitable adsorption free energy and shows high ORR activity. [ABSTRACT FROM AUTHOR]