Interrelated functionalities of hierarchically CNT/CeO2/Pt nanostructured layers: synthesis, characterization, and electroactivity

Abstract

We present a free-standing catalyst layer comprising current collector/CNTs (catalyst support)/CeO(2)/Pt (catalyst) nanostructured layers, each layer constructed upon the one below it. FESEM and TEM showed that a CeO(2) layer has a fluffy morphology recalling the texture of cotton, whereas Pt nanoparticles assemble into cauliflower or broccoli-like arrangement. New insights have been gained into the effect of CeO(2) on the structural properties of the beneath CNTs layer and on the above Pt layer. First, by means of Raman analysis, it was found that interaction of CeO(2) with CNTs induced a decrease in the crystallinity of the latter. Second, by TEM and XPS analyses, it was observed that the size of Pt nanoparticles in the CNT/CeO(2)/Pt structure was inferior to that in the CNT/Pt, implying that CeO(2) influenced the dispersion quality of Pt nanoparticles. For the first time, it is observed that CeO(2) supported CNTs undergo oxidation/reduction reactions at low potentials in the ethanol electrolyte. The electrochemical analysis showed that entities produced from those redox processes are surface adsorbed/desorbed species most likely hydroxides. This unexpected electroactivity is due to the beneath CNTs that boosted the conductivity of CeO(2). Such improved conductivity of CeO(2) has fostered the electron-transfer kinetics of ethanol at Pt as demonstrated by the decreased overpotential required to oxidize ethanol and by the specific mass activity, which was greater than that of CNT/Pt.

Fabrication of Nano Flower‐shaped Platinum on Glassy Carbon Electrode as a Sensitive Sensor for Lead Electrochemical Analysis

“…0.8 V and extends up to 1.2 V), and a single reduction peak at 0.5 V corresponding to the reduction of Pt(IV) to Pt(0) on the electrode surface. Our results were in agreement with other observational studies . Therefore, in order to deposit Pt onto GCE by chronoamperometry, the applied potential must be more negative than 0.3 V.…”

Platinum Nanoflower-Modified Electrode as a Sensitive Sensor for Simultaneous Detection of Lead and Cadmium at Trace Levels

“…is wave exhibits three potential regions: the hydrogen region (from −0.2 to +0.15 V) corresponds the adsorption/desorption of hydrogen with different energies, a broad oxidation peak for the Pt-oxide formation (commences at 0.7 V and extends up to 1.2 V), and a single reduction peak at 0.5 V corresponding to the reduction of Pt(IV) to Pt(0) on the electrode surface. e result is in agreement with previous studies [21][22][23]. erefore, in order to deposit Pt onto the GCE by chronoamperometry, the applied potential must be lower than 0.3 V.…”

A novel thermophotocatalyst of mixed-phase cerium oxide (CeO2/Ce2O3) homocomposite nanostructure: Role of interface and oxygen vacancies

“…The most significant observation in the spectra is the presence of additional peaks at 891.9 eV and at 909.7 eV which are attributed to Ce 3 þ oxidation state [15]. The binding energy peaks at 919.3, 888.2, 900.3 eV are attributable to Ce 4 þ oxidation state [11,16,17]. Fig.…”