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.