Finite Element Method Study of Nanostructured Metal Oxide Based on NiO for Nonenzymatic Urea Sensors

Urea electrooxidation has attracted increasing attention because urea is an essential biomarker for diagnosing kidney conditions. Most urea sensors are based on the enzyme; however, enzyme-based sensors have a moderately complicated assembling method [1] due to poor stability. Different from the bulk diffusion of urea in the enzymatic urea oxidation [2], the nonenzymatic urea oxidation has reactions between the reductive and oxidative at the electrode surface [3]. Moreover, in order to use nonenzymatic urea sensors in a biomedical application area, high conductivity and catalytic activities are required. Therefore, a study of nonenzymatic urea sensor on a nanostructured electrode is of substantial interest.For urea detection, various metal oxides, such as ZnO [4], CuO [5], and [6], have been broadly proposed. Practically, catalysts were studied extensively for urea electrooxidation due to successful long-term operation [7]. Typical nonenzymatic catalysts for urea electrooxidation mainly focused on designing new nanostructures and maximizing their catalytic ability. However, quantitative models integrating the physical, chemical, and geometrical design properties still need improvement to develop sensor devices. The urea reaction occurs on the surface of nanostructured metal oxide. Thus, the effect of electrode geometry on the electrochemical reactions is motivated to explore urea sensors application.In the present study, we studied three different structures such as nanorods, nanoflakes, and nanoparticles, for the nonenzymatic electrochemical sensor. Additionally, we developed a new analytical model to understand the nonenzymatic urea sensor using the finite element method. To further adjust the model, the morphology and the composition of the catalysts were investigated using transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The catalysts showed remarkable electrochemical achievement with acceptable linear sensitivity and selectivity to urea electrooxidation. Comprehensive information of the modeling concerning as a catalyst in the nonenzymatic urea sensor will be given.References FATEMA, Kamrun Nahar, et al. New of Active Material Based on YInWO4-G-SiO2 for a Urea Sensor and High Performance for Nonenzymatic Electrical Sensitivity. ACS Biomaterials Science & Engineering, 2020.Debata, Suryakanti, et al. Design of CdV2O4-V6O13 micro flowers for non-enzymatic electrochemical detection of urea. In AIP Conference Proceedings, vol. 2115, no. 1, p. 030058. AIP Publishing LLC, 2019.YOON, Jaesik, et al. Silver-Nanoparticle-Decorated NiOOH Nanorods for Electrocatalytic Urea Sensing. ACS Applied Nano Materials, 2020, 3.8: 7651-7658.YOON, Jaesik, et al. Ag/ZnO Catalysts with Different ZnO Nanostructures for Non‐enzymatic Detection of Urea. Electroanalysis, 2019, 31.1: 17-21.Goda, M. A., et al. Enhanced Electrocatalytic Oxidation of Urea at CuOx-NiOx Nanoparticle-Based Binary Catalyst Modified Polyaniline/GC Electrodes. Journal of The Electrochemical Society, 2020 167(6), 064522.Tyagi, Manisha, et al. NiO nanoparticle-based urea biosensor. Biosensors and Bioelectronics 2013, 41:110-115.BARAKAT, Nasser AM, et al. Influence of nitrogen doping on the electrocatalytic activity of Ni-incorporated carbon nanofibers toward urea oxidation. International Journal of Hydrogen Energy, 2017, 42.34: 21741-21750.