Engineering Active Sites in CeO ₂ by Nickel Doping for Efficient Water Splitting and Green Energy Production by Hydroelectric Cells

This study focuses on the development and analysis of a device known as hydroelectric cell. It generates electricity directly from water by splitting it into H₃O⁺ and OH^- ions at room temperature. This eco-friendly device also produces hydrogen gas as a byproduct. CeO₂ and Ni-doped CeO₂ nanoparticles were synthesized via the coprecipitation method and thoroughly characterized. X-ray diffraction confirmed their crystalline fluorite structure, while Raman spectroscopy and FTIR analysis revealed the presence of oxygen vacancies induced by nickel doping. Field-emission scanning electron microscopy showed a well-dispersed polyhedral morphology, and Brunauer-Emmett-Teller analysis indicated a significant enhancement in surface properties. The surface area increased from 34.83 m²/g for pristine CeO₂ to 113.18 m²/g for (3M%) Ni-CeO₂, with a pore size of 7.5 nm and a pore volume of 0.1653 cm³/g. The fabricated 4 cm² hydroelectric cells achieved an open-circuit voltage of 0.9 V and short-circuit currents of 8.98, 15.03, 40.0, and 12.0 mA for CeO₂, (1M%) Ni-CeO₂, (3M%) Ni-CeO₂ and (5M%) Ni-CeO₂, respectively. Electrochemical impedance spectroscopy confirmed enhanced ionic diffusion under wet conditions, with the 3M% Ni-CeO₂ hydroelectric cell showing the lowest impedance (∼16 Ω). The 4-fold increase in current generation from pristine CeO₂ to (3M%) Ni-CeO₂ underscores the role of nickel in enhancing water dissociation, highlighting the potential of these hydroelectric cells for sustainable green energy applications.