Synthesis, Characterization of Nanostructured Rhodium Films and their Electrochemical Behavior towards Carbon Monoxide Oxidation

Abstract

Rhodium nanostructured thin film catalysts were prepared by pulsed laser deposition. The depositions were performed under vacuum and at different He background gas pressures ranging from 1 to 5 Torr. SEM, TEM, X-ray diffraction, and X-ray photoelectron spectroscopy were used to evaluate the morphology, the structure, the surface composition, and the electronic structure of the catalysts. Their electrochemical properties were studied towards CO stripping measurements in acidic solution; a reaction of critical issue to liquid fuel cells. It was discovered that rhodium (Rh) film deposited under 5 Torr of He background pressure showed the highest electroactive surface area, and the lowest onset potential of CO oxidation demonstrating an enhancement of the CO poisoning resistance. The reason for such enhanced electrocatalytic activity is ascribed to the high porosity and roughness of the Rh surface. Compared to Pt films made under similar processing conditions (5 Torr of He), Rh film displayed higher roughness factor of 58.5 (vs. 30 for Pt), a net charge due to oxidation and desorption of the CO adlayer of 385 μC cm −2 (vs. 350 μC cm −2 for Pt), and an onset potential for CO oxidation of 30 mV less anodic than that at Pt electrode.

Highly Active and Stable Pt3Rh Nanoclusters as Supportless Electrocatalyst for Methanol Oxidation in Direct Methanol Fuel Cells

“…We observed the overlapping of Rh 3d 3/2 peak by Pt 4d 5/2 . This could be due to the presence of rhodium oxide species in the sample as observed by Saidani et al 47 XPS results indicate a mixture of metallic and oxide state of Rh, and this mixture was shown to enhance the oxidation of carbon monoxide and could play a role as an oxygen source for CH 3 OH oxidation as explained by Park et al 35 Also the atomic weight percentage composition calculated from XPS analysis confirms a 3:1 ratio of Pt and Rh in the Pt 3 Rh nanocluster.…”

Effect of target–substrate distance onto the nanostructured rhodium thin films via PLD technique

“…There are few reports on the Rh thin films fabricated via pulsed laser deposition (PLD) technique (Drogoff et al 1999;Saidani et al 2011). The nanostructured Rh thin films fabricated via PLD technique are reported in this present paper.…”

“…The large nanostructured surface of metallic Rh enhances its catalytic properties (Stempel et al 1998;Masek et al 1995;Dus et al 2008). Besides these, rhodium has potential application in microelectronics (Drogoff et al 1999;Herd et al 1983), gas sensors (Lin et al 2002;Saidani et al 2011) and as a First Mirror (FM) in the optical diagnostics of fusion devices (Marot et al 2007(Marot et al , 2008a.…”