Tuning the Electrochemical Performance of CuO Nanoparticles via Hydrothermal Synthesis

Recent research has focused on synthesizing excellent and inexpensive transition metal-based oxides as efficient electrocatalysts for electrochemical water splitting and energy storage applications, which is challenging. Herein, CuO nanoparticles were synthesized via a hydrothermal process at three different temperatures (180°C, 200°C, and 220°C) to investigate how synthesis temperature affects their electrochemical performance. The synthesized CuO nanoparticles were thoroughly characterized using x-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) surface area analysis, diffuse reflectance spectroscopy (DRS), and scanning electron microscopy (SEM). Electrochemical measurements, including cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS), revealed that CuO nanoparticles synthesized at 180°C exhibited the highest specific capacitance of 1004 F g⁻¹ at 1 A g⁻¹ and remarkable electrocatalytic activity for HER (240 mV@ 10 mA cm^-2). This enhancement is attributed to their optimized morphology and increased surface area (9 m²/g). These findings demonstrate that the synthesis temperature plays a crucial role in tuning the properties of CuO nanoparticles, making them promising candidates for advanced energy storage systems and sustainable hydrogen production.