Modification of Nickel Foam as highly active and stable bifunctional electrode material for industrial water splitting

Abstract

Renewable energy offers the potential for a sustainable and eco-friendly energy future for the planet. Solar, wind, hydropower, biofuels, and other renewable energy sources are the key drivers of the shift toward green energy systems that aggregated a significant expansion in their generation capacity in recent years. In addition, hydrogen is a versatile energy carrier and storage medium known for its high energy density of 141.9 MJ/kg . Due to its non-polluting properties and synthesis opportunity from earth abundance water, hydrogen became one of the most attractive sources of energy in future. Electrochemical water splitting is the key process which encompasses the critical reaction hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) to produce clean hydrogen using external energy sources. To produce hydrogen at low cost, stable and cheap electrocatalyst is needed. To progress the advancement of highly active, efficient and low cost electrocatalyst, nickel foam is chosen for thermal treatment varying duration as it is a promising non-noble substrate material exhibits excellent conductivity and robust mechanical properties. It is found in this study that nickel foam is annealed at 600° C for one hour shows overpotential of 377 mV at current density 10mA/cm2 for OER and annealed at 500° C for half an hour shows the best performance among samples for HER with overpotential 146mV at 10 mA/cm2 under 1.0 M KOH alkaline condition, due to the resulted combination of porous hole and nickel oxide active sites. In addition, produced electrodes show excellent full cell performance in industrial water splitting condition in 6.0 M KOH solution with only 2.33 Vcell to achieve 500 mA/cm2 and exhibits stable long-term durability. The simplicity of synthesis process makes it highly reproducible to overcome the challenges in hydrogen production due to high cost noble metal catalysts, limited stability and complex synthesis process.