Investigation of Synergistically Developed p-Co₃O₄/n-ZnHoCuO based Junction for Enhanced Photocatalytic, Electrocatalytic, and Energy Storage Applications

In this work, we have reported p-Co₃O₄/n-ZnHoCuO junction growth via a cost-effective and straightforward co-precipitation synthesis route for the first time. The structural study was investigated by employing XRD and FTIR spectroscopy. An optical study was carried out by UV–visible spectroscopy. Whereas the surface morphology and elemental analysis were analyzed using SEM and EDX. TEM analysis was included to explore the internal texture of the p-n junction. In the meantime, the XPS demonstrated that Cu, Ho-doping in ZnO and coupling with Co₃O₄ resulted in the production of lattice defects and oxygen vacancies in ZnO, along with different oxidation states of Ho, Cu, Zn, Co, and O. In this context, the photocatalytic activity was investigated with the help of two different dyes, such as MB and MO dyes, under sunlight irradiation. As-synthesized material, when employed to fabricate the electrode material and assess its potential for supercapacitor applications, demonstrated an outstanding specific capacity of 1812.90 C/g at 7.5 A/g, as measured via GCD testing, highlighting its potential for supercapacitor applications. Additionally, it demonstrated a satisfactory electrochemical and electrocatalytic properties for the as-fabricated junction, OER activity and energy storage capabilities of such materials have been confirmed by coupling contact. The calculated Tafel slope was 43.14 mV dec⁻¹ shown by the p-n junction catalyst's redox activity. At a current density of 10 mA cm⁻², the developed electrocatalyst had a low overpotential of 115 mV. The effects of Cu, Ho-doping on ZnO and the coupling of Co₃O₄ support emphasize the exceptional benefits of electrochemical performance and enhance its potential for use in effective photocatalysis, electrolysis, and energy storage technologies.