Cost effective and facile low temperature hydrothermal fabrication of Cu2S thin films for hydrogen evolution reaction in seawater splitting

Electrolysis of seawater gets an attention to produce hydrogen for renewable energy technology. It significantly reduces the use of fresh water instead of seawater. Development of low temperature fabrication of electrocatalyst can explore seawater splitting by avoiding chloride reduction during the hydrogen production. In the present work, we fabricated low temperature hydrothermal growth of Cu₂S electrocatalyst on Ni foam at constant temperature of 80 °C at different growth times of 1–3 h. The prepared Cu₂S electrocatalyst grown for 1 h exhibited low overpotentials of 76 and 118 mV at 10 mA/cm² (289 and 358 mV overpotentials at 100 mA/cm²) in 1 M KOH deionized water and seawater, respectively for hydrogen evolution reaction (HER). The Tafel plot of Cu₂S catalyst grown for 1 h showed lesser Tafel slope value of 128 mVdec^?1 than that of other growth times 2 h (136 mVdec^?1) and 3 h (142 mV dec^?1) indicating elevated electrocatalytic behaviour of Cu₂S grown for 1 h. Electrochemical impedance spectroscopy (EIS) showed charge transfer resistance of 12.8Ω, 19.6 Ω and 25.7Ω, for Cu₂S grown for 1, 2 and 3 h, respectively, this lower charge transfer resistance indicated higher charge transfer properties. The Cu₂S electrocatalyst grown for 1 h sustained retention of 80% after 12 h continuous stability test. Therefore, the cost-effective and low temperature fabrication of Cu₂S electrocatalyst proceeds for development of largescale seawater splitting for hydrogen production.