In Situ synthesis and immobilization of Co₃O₄ nanowalls on kanthal substrate using a rapid direct heating approach

Conventional synthesis methods such as hydrothermal or chemical vapor deposition often involve multi-step processes, long processing times, high energy consumption, or require expensive equipment. In this study, a novel one-step Direct Heating (DH) method for the in-situ synthesis and immobilization of Co₃O₄ nanowalls on a kanthal coils has been demonstrated. DH method offers a simple, rapid, and energy-efficient approach, allowing for the synthesis and immobilization of Co₃O₄ nanomaterials in just 20 min with only 30 W of electrical power. The formation of Co₃O₄ nanowalls was confirmed through X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and field emission scanning electron microscopy. These characterization techniques consistently showed that the nanowalls became larger with increasing heating duration. The optimized Co₃O₄ nanowalls exhibited a specific capacitance of 193 F/g, with a band gap ranging from 1.81 eV to 2.11 eV. This immobilization of Co₃O₄ nanowalls using DH method on resistive kanthal substrates presents significant advantages for practical applications in supercapacitors, enabling their integration into electronic devices such as wearable technology.