Interaction of NO during cathodic polarization in alkaline conditions at the interface of Pt-nanostructures supported on C and TiO2-C

The electroreduction of nitric oxide (NO) in alkaline media was carried out on Pt nanoparticles (5 wt.% Pt), which were synthesized by the carbonyl route. The as-prepared materials were supported on Carbon Black (XC-72R, C) and TiO2-C composite (10 wt.%TiO2) and deposited on glassy carbon (GC) electrode. Xray Diffraction (XRD), CO-stripping and hydrogen adsorption-desorption (H-upd) analysis were employed to characterize the structure and electrochemical properties. According to XRD patterns, the particle size increases from 3.95 to 8.98 nm due to the interaction of Pt with TiO2 in the carbon matrix. This modification promotes a better performance during CO-oxidation and proton adsorption-desorption. As a consequence, the performance toward NO-reduction was more important in TiO2-C composite, linked with the electrochemical active-surface area and chemical surface area relationship (ECSA/CSA). It was found that the mechanism for the reduction of nitric oxide toward nitrogen is a bi-functional process with coupled chemical and electrochemical interfacial-reactions with NH2 specie as intermediate, as demonstrated by the induced reduction reaction of NO2- and NO2- + NO, and UV-vis spectrometry. 2014 Elsevier Ltd. All rights reserved.