Instrumental details

EPOCH2 microplate reader (Biotek) spectrophotometer was used for the study of the absorption spectra. The changes of surface morphology have been observed using scanning electron microscope [FE-SEM (Zeiss, Merlin)] instrument, worked at an using accelerating voltage 20 V to 30 kV and structural morphology by using transmission electron microscopy (TEM), FEI Tecnai-G2. Atomic force microscopy (AFM) is carried out over a glass substrate of the 1 × 1 cm² area using AFM –NT-MDT (NTEGRA PRIMA, Russia). The Cyclic voltammetry (CV) at scan rate 0.05 V and Differential pulse voltammetry (DPV) and EIS measurements were performed in Autolab (PGSTAT,302, The Netherlands) and PS Trace Palm Sens3 (Handheld Potentiostat/Galvanostat), The Netherlands, by using a conventional three electrode cell set-up with screen printed electrode (Palm Sens, The Netherlands, Model number IS−1) having working electrode (Diameter = 2 mm), counter electrode (Area = 3 mm²) and reference electrode(Area = 1 mm²) which is modified with composite materials. The Counter electrode is made up of same conducting graphitic ink as in working electrode while reference electrode is made up of AgCl. CV, DPV and EIS measurements are carried out without N-purging.