Electrospun ferric ceria nanofibers blended with MWCNTs for high-performance electrochemical detection of uric acid

Abstract

In this work, ferric ceria nanofibers (FC NFs) with different iron contents were successfully fabricated through electrospinning followed by calcination at 550 °C. The resultant FC NFs were blended with multi-walled carbon nanotubes (MWCNT@FC) and utilized to modify the glassy carbon electrode (GCE) for uric acid (UA) detection. The XRD patterns revealed that FCs NFs have cubic lattice structure. The Raman and X-ray photoelectron spectroscopy (XPS) were confirmed the presence of oxygen vacancies with Fe(II)/Fe(III) and Ce(III)/Ce(IV) chemical states of the surface ions. The surface morphology was investigated through scanning electron microscopy (SEM) and particle size analysis was performed using transmissions electron microscopy (TEM). The electrochemical properties of MWCNT@FC NFs were evaluated through cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods under varied conditions. The results demonstrated the crucial effects of Ce/Fe molar ratio on the electrocatalytic performance due to the sufficient oxygen vacancies originating from the incorporation of Fe3+ ions into ceria (CeO2). Furthermore, blending with 70 wt% MWCNT (MWCNT70@FC) gave rise to a significant improvement on the electrical conductivity. The MWCNT70@FC-2 modified GCE composite with Ce/Fe molar ratio of 1:1 displayed high performance towards UA detection at 6.0 pH.The detection limit of 0.3 μM was achived with wide linear range from 0.5 μM to 500 μM. The MWCNT70@FC-2 demonstartedadequate stability and reproducibility for urice acid detection. The high selectivity and accuracy was further established for prepared MWCNT@FC-2 composite sensor by detecting UA in real biological samples. The obtained results were precise and reproducible.