Electrochemical preparation and characterization of platinum nanoparticle modified metal oxide electrodes: investigation of electrochemical behavior oxygen and formaldehyde

The demand for energy has been increasing rapidly in recent years. Fuel cells, which are one of the alternative energy sources to meet this demand, are preferred because of their environmental friendliness, high efficiency and sustainability. Fuel cells can produce energy by reducing oxygen at the cathode and oxidizing formaldehyde at the anode. The use of carbon nanotubes, metal nanoparticles and metal-metalloxide composites for the modification of electrodes has been widely researched in recent years. In this study, nanostructured tellurium, manganese and ruthenium oxide mixture (RuOx-TeOx, TeOx-MnOx) binary films were deposited on the carbon nanotube (CNT) by pulsed deposition (PD) technique and then Pt nanoparticles were modified on this surface. Modified electrodes were characterized by Cyclic Voltammetry (CV), High Resolution Transmission Electron Microscope (HRTEM). Electrochemical reduction of oxygen for cathode reaction, electrochemical oxidation of formaldehyde for anode reaction were investigated by voltammetry. In experimental studies, phosphate buffer pH (2-12), acid types, metal oxide mole ratio, pulse potential, Pt4+ concentration and number of cycles, O2 saturation time, scan rate, chronoamperometry, O2 electron number etc. parameters are optimized. At the PtNPs/RuOx-TeOx/CNT/GCE and PtNPs/MnOx-TeOx/CNT/GCE electrodes, was chosen as pH 2 HClO4 acid for ORR, 0.1 M NaOH for formaldehyde. The working range for PtNPs/RuOx-TeOx/CNT/GCE was found as 1-50000 µM and Limit of detection(LOD) was calculated as 0.5 µM. The working range for the PtNPs/TeOx-MnOx/CNT/GCE was 100-60000 µM and LOD was calculated 50 µM. For real sample analysis, the determination of formaldehyde in Gediz River was tested on PtNPs/RuOx-TeOx/CNT/GCE and PtNPs/TeOx-MnOx/CNT/GCE. The recovery of formaldehyde was between 99% and 101%.