Graphene Supported NiFe-LDH and PbO₂ Catalysts Prepared by Plasma Process for Oxygen Evolution Reaction

The development of efficient catalysts for water electrolysis is crucial for advancing the low-carbon transition and addressing the energy crisis. This work involves the fabrication of graphene-based catalysts for the oxygen evolution reaction (OER) by integrating NiFe-LDH and PbO₂ onto graphene using plasma treatment. The plasma process takes only 30 min. Graphene's two-dimensional structure increases the available reaction surface area and improves surface electron transport. Plasma treatment further improves catalyst performance by facilitating nanoparticle attachment and creating carbon defects and sulfur vacancies. Density functional theory (DFT) calculations at the PBE provide valuable insights into the role of vacancies in enhancing catalyst performance for OER. The catalyst's conductivity and electronic structure are greatly impacted by vacancies. While modifications to the electronic structure increase the kinetics of charge transfer, the vacancy structure can produce more active sites and improve the adsorption and reactivity of OER intermediates. This optimization of intermediate adsorption and electronic properties leads to increased overall OER activity. The catalyst NiFe-PbO₂/S/rGO-45, synthesized through plasma treatment, demonstrated an overpotential of 230 mV at 50 mA·cm^-2 and a Tafel slope of 44.26 mV dec^-1, exhibiting rapid reaction kinetics and surpassing the OER activity of commercial IrO₂. With its excellent performance, the prepared catalyst has broad prospects in commercial applications such as water electrolysis and air batteries.