Cost‐Effective <i>Tulasi</i> Extract Synthesis of Spinel Ag‐NiFe ₂ O ₄ NPs: Its Enhanced Electrochemical Mercury (Hg ⁺ ) Spotting and Photo‐Dye Degradation Applications

ABSTRACT The sustainable development of spinel Ag doped NiFe 2 O 4 nanoparticle (ANF NPs) was successfully synthesized by the combustion method using green ( Tulasi) extract as a fuel. The structural parameters of synthesized NPs was well examined through various spectral studies such as PXRD, SEM‐EDAX, FT‐IR, and UV–vis spectroscopy. The recorded results confirms ANF NPs is a more optimistic with controlled grain size (d = 16 nm). The influence of Ag doped NiFe 2 O 4 nanoparticle on their electrochemical properties was effectively examined by cyclic‐voltammetry (CV) and electrochemical impedance spectroscopy (EIS) under 0.1M KCl with 3‐electrode assembly. The outcomes of prepared ANF‐graphite electrode directs an excellent electrochemical‐sensing activity on mercury detection at various scan rates of 3 mV/s. The impact of ANF NPs on photocatalytic properties was studied by using UV–vis absorbance technique. This describe the ability of ANF NPs as an advisable photocatalyst based on its photocatalytic performance on Malachite Green (MG) dye found to be 98.8 % for 135 min under Sunlight irradiation. The half‐time (t 1/2 ) for photo‐decolouration analysis of ANF NPs on MG dye was found to be 40 min ascertained by plotting (C/C 0 ) v/s time. This research work influences a new‐insights into the electrochemical sensing on different chemical molecules and toxic pollutants.