| Full text | |
| Author(s): |
Neves, Joao V. T.
;
Aristides-Barros, Stephanie S.
;
Trench, Aline B.
;
Costa, Ivani M.
;
Santos, Mauro C.
;
Salazar-Banda, Giancarlo R.
;
Eguiluz, Katlin I. B.
Total Authors: 7
|
| Document type: | Journal article |
| Source: | Electrochimica Acta; v. 549, p. 17-pg., 2026-02-10. |
| Abstract | |
Pd-based anodes for alcohol oxidation suffer from surface poisoning and sluggish kinetics. Here, we developed Pd-Nb2O5/C nanocomposites to improve ethanol electrooxidation kinetics and CO tolerance in alkaline media. Orthorhombic Nb2O5 prepared by the Pechini route was combined with fcc Pd nanoparticles via polyol reduction, yielding Pd(x)-Nb2O5(y)/C nanocomposites with x:y = 100:0, 70:30, 50:50, 30:70, 0:100. Rietveld-refined Xray diffraction confirmed phase purity and showed similar Pd crystallite sizes (4.46 nm for Pd/C and 4.92-5.08 nm for Nb2O5-containing catalysts). Transmission and scanning electron microscopies coupled with energydispersive X-ray spectroscopy reveal uniformly dispersed Pd nanoparticles on Nb2O5 and carbon. UV-Vis diffuse reflectance indicated a band gap of 3.10 eV, and chopped-light photocurrent measurements confirm the strong ultraviolet responsiveness of Nb2O5. X-ray photoelectron spectroscopy reveals that Pd(0.5)Nb2O5(0.5)/C had the highest Pd degrees content (58.99 %). Electrochemical testing demonstrates that, relative to Pd/C, optimized Pd(0.5)Nb2O5(0.5)/C reduces the ethanol oxidation onset potential by up to 160 mV, increases poisoning tolerance by a factor of five at a fixed potential, and raises the current density from 1.59 to 1.76 mA cm-2. Under light irradiation, the current density increases from 1.07 to 2.10 mA cm-2, accompanied by improved stability and extended durability, attributed to light-induced electron-hole generation and enhanced OH- adsorption. These results highlight the synergistic contribution of oxide-metal interactions and photoactivation to ethanol oxidation and provide insights for designing efficient catalysts for alkaline fuel cells. (AU) | |
| FAPESP's process: | 21/14394-7 - Use of Vulcan XC-72 carbon modified with fluorine and/or cerium doped niobium nanostructures in the electrogeneration of H2O2 for degradation of endocrine disruptors by advanced electrochemical oxidative processes |
| Grantee: | Aline Barrios Trench |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 22/15252-4 - Nanostructured electrocatalysts for application in direct alkaline-acid fuel cells of glycerol |
| Grantee: | Mauro Coelho dos Santos |
| Support Opportunities: | Program for Research on Bioenergy (BIOEN) - Regular Program Grants |