Fabrication of Nanostructured Pd Thin Films Using Aerosol-Assisted Chemical Vapor Deposition for the Nonenzymatic Electrochemical Detection of H₂O₂

Abstract

An improved and facile aerosol-assisted chemical vapor deposition (AACVD) process for the production of palladium thin film on indium tin oxide (PdNP-ITO) electrodes was described and applied for the electrochemical detection of hydrogen peroxide (H 2 O 2 ). The detailed characterization of the films by X-ray diffraction (XRD), scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS) analysis proved the high crystallinity and phase purity of the nanosized metallic palladium films without the evolution of any elemental impurities from the precursor compound. The as-prepared electrodes were used for nonenzymatic amperometric H 2 O 2 detection via electrochemical reduction. The LOD was 40.8 nM with a high sensitivity of 760.84 μA/(μM cm 2 ). From the experimental scan rate variation analysis, the reduction of H 2 O 2 on the PdNP-ITO electrode surface was determined to be adsorption controlled. For this process of adsorption, we calculated the number of electrons involved during adsorption (n), the charge transfer coefficient (α), and, finally, the rate constant (k s ). The process of adsorption of H 2 O 2 on each of the characteristic metallic planes was further studied via Monte Carlo simulations (MCSs). We accounted for both molecular O 2 and H 2 O during the simulations to understand the effects of oxygen and solvent on adsorption since all experiments were conducted in an air-saturated solution. Several numbers of the adsorbate−metal substrate configurations were obtained for the simulations on each crystalline Pd plane, confirming the firm adsorption of H 2 O 2 in the presence of O 2 and H 2 O. Based on analysis of the results from the electroanalytical procedures and MCSs, possible reduction reaction mechanism pathways were proposed.

Metal Nanoparticles for Electrochemical Sensing: Progress and Challenges in the Clinical Transition of Point-of-Care Testing

“…However, in excessive content it can cause gout and hyperuricemia [ 176 ]. During the production of antioxidant UA through the xanthine oxidation process, H 2 O 2 is formed as a short-lived oxidizing agent that can show acute toxicity [ 177 ]. Usually, only a trace amount of H 2 O 2 (10–100 nM) is found in the circulated blood, which makes detection an arduous task [ 177 ].…”

“…During the production of antioxidant UA through the xanthine oxidation process, H 2 O 2 is formed as a short-lived oxidizing agent that can show acute toxicity [ 177 ]. Usually, only a trace amount of H 2 O 2 (10–100 nM) is found in the circulated blood, which makes detection an arduous task [ 177 ]. While glucose detection requires a wide linear range, other SBMs necessitate a highly sensitive approach.…”

Hollow Reticular Shaped Highly Ordered Rice Husk Carbon for the Simultaneous Determination of Dopamine and Uric Acid

“…The Figure S5 shows that such contribution is likely present only below 25 mV/ s scan rate. So, for the adsorption-controlled process we used Laviron's equation to determine the number of electrons transferred during DA and UA oxidation [19]:…”

“…The heterogenous rate constant for electron transfer (k°) was determined using the following equation [19,21,41]:…”

“…The field of electrochemical sensor (ECS) fabrication is becoming an ever-growing research area with the increasing need for quick, cost-effective, accurate, and easy-to-use methods for detecting disease biomarkers and environmentally hazardous chemicals [11,13,[17][18][19][20]. On top of these advantages, proper analysis of the data from various electroanalytical techniques (EATs) can provide useful information regarding the electron transfer process of analytes at the interfacial region, and the kinetics of electron transfer process [13,19]. One of the most important criteria of an effective ECS is the working electrode (WE).…”