# Doping Effects on the Performance of Paired Metal Catalysts for the Hydrogen Evolution Reaction

## TL;DR

This study investigates how nitrogen doping levels influence the catalytic activity of paired Co and Pt metal sites on nitrogen-doped graphene for hydrogen evolution, revealing enhanced performance with increased N concentration.

## Contribution

It demonstrates that increasing nitrogen doping improves HER activity by modifying transition metal active sites, offering insights for designing better fuel cell catalysts.

## Key findings

- HER activity increases with N doping concentration.
- Hydrogen adsorption free energy varies from 0.23 to -0.42 eV.
- N doping enhances Co atom activity for H adsorption.

## Abstract

Metal heteroatoms dispersed in nitrogen-doped graphene display promising catalytic activity for fuel cell reactions such as the hydrogen evolution reaction (HER). Here we explore the effects of dopant concentration on the synergistic catalytic behaviour of a paired metal atom active site comprised of Co and Pt atoms. The metals are coordinated to six atoms in a vacancy of N-doped graphene. We find that HER activity is enhanced with increasing N concentration, where the free energy of hydrogen atom adsorption ranges from 0.23 to -0.42 eV as the doping changes from a single N atom doped in the pore, to fully doped coordination sites. The results indicated that the effect of N is to make the Co atom more active towards H adsorption and presents a means through which transition metals can be modified to make more effective and sustainable fuel cell catalysts.