Papers by Keyword: Formic Acid Oxidation

Abstract: Pd supported on TiO₂-embedded carbon nanofibers (Pd/TECNF) were prepared as the anode catalyst for direct formic acid fuel cells (DFAFCs) using an electrospinning technique. The effect of the TiO₂ content on the catalytic activity of Pd was investigated based on the electrochemical measurements of cyclic voltammetry (CV), chronoamperometry (CA), and also characterization by XRD, EDX, FE-SEM and CO stripping. The activity was significantly increased by an increase in the TiO₂ content up to Ti/C=0.44 and then decreased. The maximized activity was improved eight fold by the TiO₂ addition. The increased activity was attributed to the increased electrochemically active surface area due to the modified surface of the nanofibers.

Abstract: Near-monodisperse Pd and PdCo nanoclusters were synthesized by physical vapor deposition using a plasma-gas-condensation cluster deposition system and tested for catalyzing formic acid oxidation. Under the condition of high vacuum and inert gas, NCs with clean surface and uniform size were obtained. The cyclic voltammetry tests revealed that the electrochemical surface area was increased from 49.7 m² g^-1 to 51.7 m² g^-1 and the peak current density of catalyzing FAO was raised from 0.115 mA cm^-2 to 0.125 mA cm^-2 when about 12wt. % Co element was added. Additionally, the tolerance to CO poisoning of Pd could also be improved by the addition of Co. The result indicated that this method offered a chemical-free way to prepare clean and efficient Pd-based nanoscale catalytics and encouraged deeper exploration for electrochemichal catalytic reactions.

Abstract: Formic acid oxidation was studied at low-index Pt single crystals (model systems) as well as at the platinum catalyst supported on high area carbon (real catalyst) in HClO4. The Pt single crystals were characterized by LEED. The LEED patterns obtained after a mild heating of flame-annealed crystals have shown clean, well ordered unreconstructured surfaces. Pt-C supported catalyst was analyzed by AFM and STM in air and by XRD. AFM and STM images revealed the presence of Pt-C agglomerates of several tenth of nm consisting of Pt particles ranged from 2 nm to 6 nm. The electrocatalytic activity of these catalysts in formic acid oxidation increased in a sequence: Pt(100) < Pt(110) < Pt-C/GC < Pt(111).

Abstract: The formic acid oxidation on Pt/Ru nanoparticles in acid solution over the temperature range 298-333 K has been studied by thin-film rotating disk method (RDE). Transmission electron microscopy in combination with scanning tunneling microscopy was used to determine the size (4.3 ± 0.3 nm) and shape (cuboctahedral) of the particles. Kinetic analysis revealed that at elevated temperatures (313 K, 333 K) the reaction rate is much higher than at room temperature (295 K), indicating that formic acid oxidation on supported Pt/Ru catalyst is a highly activated process. Based on experimental kinetic parameters we propose that the HCOOH oxidation on the PtRu alloy most likely follows a dual pathway, but the branching ratio is still very high, i.e. Pt-like. The principal effect of opening the dehydration channel at steady-state (via the presence of Ru in the surface) is to lower the coverage of COads on Pt sites and permit the dehydrogenation path to increase in rate.