Nanocrystalline Co/Ga substituted CuFe₂O₄ magnetic nanoferrites for green hydrogen generation

The research study on the design of cobalt and gallium substituted copper nanoferrites through sol-gel auto-combustion were testify to check the photocatalytic/electrocatalytic water splitting efficiency of prepared nanoferrites for hydrogen generation. XRD study confirms the formation tetragonal phase for all fabricated nanoferrites with no additional phases of impurities. The tetragonal shaped grains with definite grain boundaries were observed from the FESEM study. The magnetic measurements show large hysteresis loop area with high magnetization of 58.45 emu/g for undoped copper nanoferrite. The catalytic behaviors of the fabricated nanocatalysts for the photo-catalytic H₂ production was determined by using 0.079 M Na₂SO₃ and 0.128 M Na₂S as the sacrificial agents, that give electron donor site during photo-catalysis under UV–visible irradiation. As compared to other compositions, Cu_0.99Co_0.01Ga_0.01Fe_1.99O₄ (x = y = 0.01) nano photocatalyst attained the highest photocatalytic activity of 18.11 mmol g_cat⁻¹. Also, the as-synthesized photocatalysts repeatability and stability were evaluated throughout repeated runs of 4 h reaction period conducted under identical circumstances. However, all electrocatalytic analysis for hydrogen evolution reaction (HER) activity were performed using three electrode arrangements (reference, counter, and working electrodes) in 0.5 M H₂SO₄ electrolyte mixture. There was a rise in overpotential at 10 mA/cm⁻² cathode current density as concentrations of Co/Ga for the synthesized nanoferrites were increased. It has been showed that CuFe₂O₄ had a high electrocatalytic HER activity. In addition, the produced nanoferrites were also examined against different type of bacterial strains, where Cu_0.99Co_0.01Ga_0.01Fe_1.99O₄ indicated maximum zone of inhibition (ZOI) against Bacillus subtilis (20 ± 0.55 mm), Salmonella typhi (12 ± 0.52 mm), Escherichia coli (16 ± 0.49 mm), and Staphylococcus aureus (12 ± 0.54 mm), respectively. Hence, with these efficient overall photocatalytic and electrocatalytic water splitting traits, the prepared nanoferrites are highly useful for the green hydrogen production applications.