Rapid phytochemical microwave-assisted synthesis of zinc oxide nano flakes with excellent electrocatalytic activity for non-enzymatic electrochemical sensing of uric acid

In the current research work, the author synthesized Zinc oxide (ZnO) NPs using crude black pepper ( Piper nigrum ) seed extract as a stabilizing, capping, and bio-reducing agent, using cost-effective and straightforward microwave irradiation techniques. The synthesized ZnO NPs analyzed for their structure, size, chemical state, elemental composition, internal and external morphology through spectroscopic and microscopic characterizations such as Powder X-ray diffraction (XRD), X-Ray Photo Electron Spectroscopy (XPS), Transmission Electron Microscope (TEM), Scanning electron microscope with energy dispersive X-ray analysis (SEM-EDAX), and Elemental mapping. The impact of three microwave irradiation times, such as 5, 10, and 15 min, upon crystallinity, morphology, and size of P. nigrum ZnO NPs was investigated. The ZnO NPs synthesized through irradiation for 10 min appeared to be more crystalline with flake-shaped morphology with an average of 30 nm size and were determined based on SEM, XRD, TEM. The electrocatalytic activity of three different microwave-assisted synthesized P. nigrum ZnO NPs-fabricated Screen-Printed Carbon Electrode (SPCE) against uric acid was studied using impedance spectroscopy and cyclic voltammetry. The detection of uric acid was performed for P. nigrum ZnO NPs-10 min/SPCE by using Differential Pulse Voltammetry (DPV) showed a sensitivity of 40.485 µAmM −1 cm −2 within the detection limit of (1.65 µM, S/N = 3) with a linear dynamic range from (50–500 µM), and a correlation coefficient of R = 0.9912. The amperometric studies of P. nigrum ZnO NPs-10 min/SPCE have optimized at potential + 0.2 V, and the calibration plot is linear over in the concentration range of (10–900 nM) with a correlation coefficient of R = 0.9952.