Potential Use of Waste in Electrocatalysis Using Foundry Sand as Electrocatalyst for the Hydrogen Evolution Reaction

Approximately 13 million tons of foundry sand (FS), a waste from the metallurgic industry, are produced worldwide annually. Although several applications for this waste have been reported, there is a lack of research regarding its application in energy production, such as the hydrogen evolution reaction (HER). Due to several metal oxides commonly present in this waste, like iron oxides, FS may have great potential for HER. Simple carbon-paste electrodes comprised of graphite and FS were prepared and tested for HER. FS, after thermal treatment, showed an onset potential near +0.39 V vs Reversible Hydrogen Electrode and a current density of approximately 16 mA cm ^‒2 at ‒0.9 V. HER geometric rate, turnover number (TON), and faradaic efficiency were 1.77 μ mol h ^‒1 cm ^‒2 , 3126, and 43.4%, respectively. Those are reasonable values compared to the ones reported in the literature, showing the potential of this waste for the manufacturing of low-cost electrodes.