DFT and experimental studies of iron oxide-based nanocomposites for efficient electrocatalysis

Abstract

The synthesis of iron oxide nanoparticles coated with graphitic carbon nitride (Fe_x-NC), and their improved electrochemical stability and corrosion resistance in an acidic electrolyte environment are reported. Our results show that the Fe_x-NC nanocomposites exhibit enhanced activity and long-term stability for the HER in a 0.5 M H₂SO₄ aqueous solution, with an onset potential of 73 mV and Tafel slope of 69 mV dec⁻¹. Furthermore, DFT calculations are carried out to represent our experimental system. Both theory and experiment strongly correlate with each other, where gC₃N₄@FeO has superior performance to the pristine gC₃N₄. It is found that the electrocatalytic activity of gC₃N₄@FeO arises from the electron transfer from FeO particles to the gC₃N₄, which form an electrostatic interaction, leading to a decreased local work function on the surface of gC₃N₄. The resulting graphitic carbon nitride shells prevented direct contact between the iron oxide nanoparticles and acidic electrolyte (H₂SO₄), so that improved stability and corrosion resistance could be achieved. This work sheds light on new efficient and durable electrocatalysts for applications in acidic environments.