<p>This study presents a novel approach to the electrochemical synthesis of rare-earth compounds that is both efficient and low in energy consumption. To overcome the technical bottleneck associated with high energy consumption per unit mass in the preparation of praseodymium-based compounds using traditional cation membrane electrochemical conversion technology, we successfully prepared a nanoscale alkaline praseodymium carbonate precursor with a regular shuttle structure in a self-designed double-chamber electrolysis reactor, employing an innovative one-step electrochemical conversion strategy. By optimizing the calcination process parameters, we produced spherical praseodymium oxide nanoparticles, both of which exhibited high purity, regular morphology, and favorable stacking properties. The novel electrosynthesis technology significantly reduces the energy consumption per unit mass of praseodymium carbonate from 2.43 to 1.34&#xa0;kW·h·kg⁻¹, achieving a 44.9% improvement in energy-saving efficiency. X-ray photoelectron spectroscopy (XPS) analysis revealed that CO₃²⁻ generated from the dissolution of CO₂ during electrolysis forms a stable PrCO₃(OH) structure with Pr. The precursor decomposed most rapidly between 600 and 700&#xa0;℃, while the duration of calcination had no significant impact on the decomposition rate of the product. A comprehensive study on electrochemical kinetics has accurately determined the overpotential (η), exchange current density (j⁰), Tafel slope (b), and electrochemical impedance parameters involved in the electrolysis process. This process offers several advantages, including low energy consumption, environmental sustainability, and operational simplicity. Furthermore, it presents a novel green synthesis strategy and theoretical foundation for preparing rare-earth oxides from rare-earth chlorides, highlighting significant application prospects in the field of rare-earth functional materials preparation.</p>