Recommended practices and benchmarking of foam electrodes in water splitting

Generation of H₂ and O₂ by electrochemical water splitting is a sustainable strategy for a greener society. Recently, attention has been paid to designing 3D porous electrodes using Fe, Co, Ni, Cu, and C foam materials as substrates to obtain larger current densities (>500 mA cm⁻²) for industrial applications. However, oversimplification of the experimental and quantitative processes for foam electrodes has made it difficult to fully understand the electrocatalytic nature and develop the proper catalysts. Hence, an objective evaluation of the electrocatalytic activity is necessary and problems associated with foam materials must be better understood, including the impact of the surface area, current density normalization, electrode thickness, electrocatalytic mass, active materials, and electrochemical measurements.