Carbon nanotube‐supported bimetallic palladium–gold electrocatalysts for electro‐oxidation of formic acid

Abstract

It is known that palladium‐based catalysts are initially very active in direct formic acid oxidation but they suffer from fast deactivation caused by a strongly adsorbed CO intermediate. Reactivation of the catalysts involving application of anodic potential may cause palladium dissolution. The aim of the present study is to increase the stability and performance of palladium‐based catalysts in direct formic acid fuel cells (DFAFCs). Preparation and characterization of palladium/multiwalled carbon nanotubes (Pd/MWCNTs) and towards formic acid oxidation via different treatments are described. The catalysts were characterized by thermogravimetric analysis (TGA), X‐ray diffraction (XRD), transmission electron microscopy (TEM) and cyclic voltammetry (CV). It was shown that the Pd and Pd–Au MWCNTs supported catalysts after reduction in H2–Ar at 200 °C (R200 treatment) were highly active in formic acid electro‐oxidation, whereas the catalysts after heating in argon at 250 °C (C250 treatment) were inactive. The catalysts after hydrogen treatment have smaller metal particles and better contact with MWCNTs support. CV, simulating reactivation of the catalysts, showed that the Pd catalyst suffers from severe Pd dissolution, whereas for the Pd–Au selective leaching of Pd is considerably slower.

Deactivation resistant Pd–ZrO2 supported on multiwall carbon nanotubes catalyst for direct formic acid fuel cells

“…However Pd/Pt catalyst exhibit better stability during operation of the DFAFC due to promoting the dehydrogenation reaction [11,12]. Investigation on the PdeAu catalysts revealed higher activity in the electrooxidation of formic acid than on commercial Pd catalysts [12,17]. Moreover, PdeAu catalyst turned out to be more resistant to a periodic regeneration by the anodic pulses than Pd [17].…”

“…Investigation on the PdeAu catalysts revealed higher activity in the electrooxidation of formic acid than on commercial Pd catalysts [12,17]. Moreover, PdeAu catalyst turned out to be more resistant to a periodic regeneration by the anodic pulses than Pd [17].…”

Recent Development of Pd-Based Electrocatalysts for Proton Exchange Membrane Fuel Cells

“…(2) PdAu alloys Chen et al [95] prepared PdAu/multiwalled carbon nanotubes (Pd-Au/MWCNTs) to increase the stability and performance of the Pd-based catalysts in DFAFCs. The catalyst was highly active in formic acid oxidation, due to the hydrogen treated catalysts have smaller metal particles and better contact with MWCNTs support.…”

Studies of oxidized carbon nanotubes in temperature range RT–630°C by the infrared and electron spectroscopies

“…The fuel cell technology has become a project of high concern due to its crucial significance for practical utilization of hydrogen (or other biofuels) energy replacing carbon, oil and gas. The application of CNTs in fuel cell and hydrogen storage systems has been described elsewhere [5][6][7]. The fuel cells operate using hydrogen, methanol or formic acid, oxygen as reactants and produce electrical current, water and in some cases carbon dioxide, being the cleanest and the most efficient energy technology.…”

“…The fuel cells operate using hydrogen, methanol or formic acid, oxygen as reactants and produce electrical current, water and in some cases carbon dioxide, being the cleanest and the most efficient energy technology. The CNTs based catalysts were shown to perform more effectively than the carbon black supported [6][7][8][9]. Recently, the Pd-Au on MWCNTs has been shown to be an efficient catalyst of formic acid electrooxidation [6,7].…”