Hierarchical flower-like CuO/carbon dots nanocomposite as advanced bifunctional electrocatalysts for clean hydrogen generation

The rapid expansion of renewable energy relies on hydrogen, and it is the energy carrier with the highest energy density. Thus, effective hydrogen production is critical for successfully transitioning to renewable energy sources. So, identifying the effectual and efficient nanocomposite for water splitting remains the priority in context with sustainable hydrogen production. In the present work, we synthesized binder-free flower like crystalline shaped CuO nanoparticles with synthesized carbon dots using green method (CuO@CDs) catalyst loaded on glassy carbon (GC) electrode, which was characterized by XRD (X-ray diffraction analysis), SEM (Scanning electron microscopy), and EDX (energy dispersive X-rays spectroscopy) to analyze its physical and structural characteristics. The optimized sample, CuO@CDs/GC has a higher porous surface and smaller particle sizes as compared to the pure CuO/GC, and CDs/GC and it showed enhanced OER (oxygen evolution reaction) and HER (hydrogen evolution reaction) activity. Specifically, it had lower over potentials of 230 mV and 297 mV (V vs RHE) for both OER and HER at 10 mA cm⁻², respectively. Moreover, the obtained Tafel slopes of 130 and 98 mV dec⁻¹ for the nanocomposite are evidence of even more efficient OER and HER processes, respectively. Furthermore, Investigation of turnover frequency (TOF) was conducted and the findings indicated improvement of inherent activities (TOF = 0.006 s⁻¹ and 0.00107 s⁻¹ at 350 mV) for OER and HER and also attained double layer capacitance (Cdl = 9.5 mF cm⁻²). Hence, CuO@CDs/GC is a promising candidate for both processes under alkaline conditions due to its enhanced electrochemical activity.