The use of CeO₂-modified Pt/C catalyst inks for the construction of high-performance enzyme-free H₂O₂ sensors

In this work, the development of novel enzyme-free electrochemical hydrogen peroxide (H₂O₂) sensors with high sensitivity and wide linear range is described. The electrochemical sensors were constructed by the physical modification of commercial Pt/C catalysts with CeO₂ metal oxide nanoparticles. X-ray diffraction (XRD), transmission electron microscopy (TEM), N₂-adsorption, and Raman spectroscopy methods were used to characterize the metal oxide nanoparticles. The CeO₂ particles showed fluorite-type structure with the average crystalline size of 13.8 nm. Furthermore, the Raman spectroscopy results indicated the presence of high degree of oxygen defects indicating the high redox property of the nanoparticles. The physical surface area of the metal oxide nanoparticles was determined to be 68.8 m² g⁻¹. The catalyst inks were prepared by mixing commercial Pt/C and CeO₂ nanoparticles with different weight ratios. The analytical performance of the sensors was studied using cyclic voltammetry (CV) and chronoamperometry (CA) methods. The results revealed that the introduction of CeO₂ nanoparticles into the catalyst layer improved the sensor performance significantly compared to Pt/C sensors. A high sensitivity of 185.4 ± 6.5 μA mM⁻¹ cm⁻² was obtained from CeO₂-modified sensors in a wide linear range of 0.01–30 mM. Depending on the obtained results it can be suggested that the novel sensor design holds a great promise for the construction of electrochemical sensors with high sensitivity, selectivity, and wide working window.