Catalytic reaction on FeN4/C site of nitrogen functionalized carbon nanotubes as cathode catalyst for hydrogen fuel cells

Abstract We utilized first-principles spin-polarized density functional theory (DFT) calculations to study the electrocatalytic reaction steps on FeN 4 /C site of carbon nanotubes. O 2 molecule can be adsorbed and partially reduced on FeN 4 /C site without any activation energy barrier. The partially reduced O 2 further reacts with H + and e − through a direct pathway (DPW) and form two water molecules without any activation energy barrier. Through an indirect pathway (IDPW), there is an activation energy barrier of ~ 0.15 eV for the formation of the first H 2 O molecule. The formation of the second H 2 O molecule through IDPW does not have any activation energy barrier.