Design of Magnetically Recyclable Ternary Fe₂O₃/EuVO₄/g-C₃N₄ Nanocomposites for Photocatalytic and Electrochemical Hydrogen Storage

Environmental protection and the need for green energy have become a fundamental concern for humanity. Herein, to obtain high-performance catalysts, ultrasonic treatment in g-C3N4, Fe2O3, and EuVO4 nanostructures effectively modified structural, optical, magnetic, photocatalytic, and electrocatalytic characteristics at the nanoscale level owing to the formation of ternary Fe2O3/EuVO4/g-C3N4 nanocomposites. The charge–discharge chronopotentiometry and cyclic voltammetry methods were utilized for examination of electrochemical performances of as-fabricated composites. Also, degradation of the selected pollutant model (Rhodamine B (5 ppm)) through a photocatalytic approach was determined through experimental and kinetic studies. The effect of the EuVO4 amount (5, 10, 15, and 20%) on the modification of ternary nanocomposites was compared to alter the morphology and optical and electrochemical properties. The recyclable magnetic Fe2O3/EuVO4/g-C3N4 nanocomposite with 15% EuVO4 achieves a high hydrogen storage capacity of 262.21 mAh g–1 in the 2 M KOH electrolyte after 15 cycles, and the apparent photocatalytic performance reaches 80.06% using visible source for removing of Rhodamine B. More importantly, the ternary Fe2O3/EuVO4/g-C3N4 nanocomposites exhibit much higher hydrogen storage capacity and photocatalytic activity than the pristine EuVO4 nanoparticles. Finally, the coexistence of EuVO4, Fe2O3, and g-C3N4 offers an essential effect in achieving superior electrocatalytic and photocatalytic activity for hydrogen storage and water treatment.