PtNPs/TeOx-MnOx decorated carbon nanotube electrodes: a dual-function catalyst for formaldehyde oxidation and oxygen reduction reaction

In fuel cell technologies, both the oxygen reduction reaction (ORR) at the cathode and the formaldehyde oxidation at the anode are crucial processes. In this study, a single electrode material was developed and evaluated for both electrodes. Multi-walled carbon nanotubes (MWCNT) were coated with tellurium oxide and manganese oxide mixtures (TeOx-MnOx) using the pulsed deposition technique. Platinum nanoparticles (PtNPs) were subsequently modified deposited on the metal oxide surface via cyclic voltammetry. The TeOx:MnOx molar ratio for optimal electrode performance was determined to be 1:20. The PtNPs/TeOx-MnOx/MWCNT/GCE (0.83 V) electrode exhibited a 13-fold increase in the peak current of oxygen compared to the bare electrode. The modified electrode was characterized by HRTEM, SEM-EDX, XPS, XRD, FTIR, and EIS analyses, which confirmed the successful integration of PtNPs and TeOx-MnOx onto the MWCNT framework and demonstrated enhanced conductivity and structural stability. Additionally, the anode performance was evaluated through formaldehyde oxidation. The peak current for formaldehyde oxidation at the PtNPs/TeOx-MnOx/MWCNT/GCE electrode increased 30.4 times compared to the bare electrode. Since formaldehyde is a hazardous substance for both the environment and human health, sensitive detection is crucial. Formaldehyde was detected using linear sweep voltammetry (LSV) within the concentration range of 0.1 -60 mmol L-1. The limit of detection (LOD) was calculated to be 50 mu mol L-1. The method was successfully applied to real river water samples, with recovery values for formaldehyde ranging from 99 % to 101 %.