NiCo2O4 nano-needles as an efficient electro-catalyst for simultaneous water splitting and dye degradation

Abstract

Developing an efficient and non-precious bifunctional catalyst capable of performing water splitting and organic effluent degradation in wastewater is a great challenge. This article reports an efficient bifunctional nanocatalyst based on NiCo₂O₄, synthesized using a simple one-pot co-precipitation method. We optimized the synthesis conditions by varying the synthesis pH and sodium dodecyl sulfate (SDS) concentrations. The prepared catalyst exhibited excellent catalytic activity for the electrochemical oxygen evolution reaction (OER) and simultaneous methylene blue (MB) dye degradation. Among the catalysts, the catalyst synthesized using 1 g SDS as a surfactant at 100 °C provided the highest current density (658 mA cm⁻²), lower onset potential (1.34 V vs. RHE), lower overpotential (170 mV @ 10 mA cm⁻²), and smallest Tafel slope (90 mV dec⁻¹) value. Furthermore, the OH˙ radicals produced during the OER electrochemically degraded the MB to 90% within 2 hours. The stability test conducted at 20 mA cm⁻² showed almost negligible loss of the electrochemical response for OER, with 99% retention of the original response. These results strongly suggest that this catalyst is a promising candidate for addressing the challenges of wastewater treatment and energy generation.