Transition metal-N4 embedded black phosphorus carbide as high-performance bifunctional electrocatalyst for ORR/OER

Designing highly active electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is an important challenge in energy conversion and storage technology. In this work, based on computational screening over 23 kinds of transition metal (TM) doping, we use first-principles study to explore the ORR and OER activity of TM-N4 embedded black phosphorus carbide monolayer (b-PC). The results show that the catalytic performance highly depends on the number of electrons in d orbital and the number of valence electrons of introduced TM atom. Moreover, we found that Co-N4-bPC (ηORR=0.31 V; ηOER=0.22 V), Rh-N4-bPC (ηORR=0.33 V; ηOER=0.62 V), Ir-N4-bPC (ηORR=0.21 V; ηOER=0.21V) can be promising candidates as bifunctional catalysts for both ORR and OER comparable or superior to TM-N4-graphene. They experience no structural distortion at 500 K. Moreover, the exfoliation energy of b-PC is lower than the graphene, and these three promising candidates show much lower formation energy comparing to that of TM-N4-graphene. Our study provides a systematical method for designing and developing high performance 2D material-based single atom catalysts (SACs) beyond graphene.