Thermoelectric Driven Self-Powered Water Electrolyzer Using Nanostructured CuFeS₂ Plates as Bifunctional Electrocatalyst

The advancement of nonprecious electrocatalysts for the overall water splitting reaction have attained great significance in producing clean hydrogen fuel (H2). Herein, we are reporting the use of a copper iron sulfide (CuFeS2) nanostructure (prepared via the hydrothermal method) as a cost-effective and high-performance bifunctional catalyst for the electrochemical hydrogen evolution reaction (HER) and oxygen evolution reactions (OER). The physicochemical characterizations such as X-ray diffraction, laser Raman, X-ray photoelectron spectroscopic, and electron microscopic studies indicated the formation of platelike CuFeS2 nanostructures. Linear sweep voltammetric analysis of the CuFeS2 electrocatalyst demonstrated its superior electrocatalytic activities for effectively driving hydrogen/oxygen evolution reactions with a lower overpotentials (η10) of 136 and 320 mV in 1.0 M KOH electrolyte. Additionally, multipotential and durability studies of CuFeS2 electrocatalyst displayed better electrochemical properties for HER and OER reactions. Finally, a lab-scale CuFeS2 water electrolyzer was fabricated that demonstrated better performance metrics with a very low voltage of 1.66 V for water splitting reactions. As proof of the concept, a self-powered water electrolyzer system comprising a thermoelectric device (to convert waste thermal energy into electricity) that can drive the CuFeS2 water electrolyzer efficiently was demonstrated, highlighting its promise as a candidate for low-cost clean energy production.