Improving the performance of porous nickel foam for water oxidation using hydrothermally prepared Ni and Fe metal oxides

Recent research trends have seen a rise in the interest in Transition Metal Oxides (TMO's) as catalysts for the Oxygen Evolution Reaction (OER). In particular, the use of inexpensive mixed TMO's such as Fe and Ni has gained much attention. While some techniques, such as electrodeposition, are widely investigated, reports into the fabrication of Fe, Ni/Fe and Ni oxides for the OER by alternative methods are sparse. To our knowledge, a study involving hydrothermal synthesis to produce all three of the aforementioned catalysts for the OER has yet to be undertaken. Additionally, the use of high surface area electrode supports to enhance the properties of the OER materials is very popular at present. Currently, industrial alkaline electrolysis uses Ni foam as an electrode due to its high porosity, three dimensional structure and low cost. Herein, the hydrothermal synthesis of nanoscale Fe, Ni/Fe and Ni oxide particles is reported. The resulting powders were subsequently used to modify Ni foam, an industrially compatible OER catalyst. The modified Ni foams exhibit improved OER capabilities when compared to the bare foam. Interestingly, the hydrothermal Ni oxide has the greatest enhancement in its OER activity compared to the mixed Ni/Fe and pure Fe oxides. Usually, electrodeposited NiFe oxides are superior OER catalysts compared to pure Ni and Fe oxides. Finally, the hydrothermal Ni oxide/Ni foam system offers a cheap and more active OER catalysts then the currently utilised anodic material for water electrolysis. This system could generate an increased amount of H2 gas for an economy searching for alternatives energy sources.