Stable NiO–ZnFe2O4 p–n heterojunction nanocomposite for dualfunctional photocatalysis and sensor applications

The design of single semiconductor nanocomposite for combined photocatalytic and sensing applications has gained considerable global attention. Herein, a NiO–ZnFe₂O₄ (NZF) nanocomposite was synthesized via a simple combustion method and systematically investigated photocatalytic and electrochemical properties. X-ray confirmed the coexistence of cubic NiO and spinel ZnFe₂O₄ phases, while SEM and EDX revealed a porous nanostructure. The band gap energy 1.6 eV, attributed to p–n heterojunction and interfacial interaction. The BET surface area of 205 m²g⁻¹ further enhanced the catalytic activity. Consequently, the NZF nanocomposite achieved 91% photocatalytic degradation of Brilliant Blue FCF under optimized conditions. Electrochemical sensing studies toward hydrogen peroxide using NZF electrodes demonstrated with a wide linear range (0.1–200 µM) and a low detection limit of 2 µM attributed to synergistic charge transfer and reduced overpotential at the heterojunction interface. Hence the NZF nanocomposite is a promising multifunctional material for environmental remediation and electrochemical sensing.