Electrochemical promotion in O2− cells during propane oxidation

Abstract

The catalytic oxidation of propane was studied in an oxygen ion conducting solid electrolyte cell at 623-773 K and atmospheric total pressure. Three catalyst-electrodes were tested, Pt, Pd and Ag. Under open circuit, the technique of Solid Electrolyte Potentiometry (SEP) was used to monitor the thermodynamic activity of oxygen adsorbed on the catalyst surface during reaction. Under closed circuit, the effect of electrochemical promotion was investigated. On Pt and Pd, the promoting effect was of the ''inverted volcano'' type. On Pt, the reaction exhibited a strong NEMCA effect; the closed circuit rate exceeded the open circuit rate by more than three orders of magnitude. On Pd, on the other hand, the effect was hardly Faradaic. On Ag, a moderate NEMCA behavior was observed and the promoting effect was purely electrophobic. Both open and closed circuit results obtained with these three catalyst-electrodes, are evaluated and compared to each other.

Ionically Conducting Ceramics as Active Catalyst Supports

“…A moderate NEMCA behavior was reported on Ag, where the catalytic rate was increased only under negative polarizations (electrophilic behavior). 304 Combustion of traces of volatile organic compounds (VOCs) at low temperatures for air cleaning is also a challenge for the catalysis community. EPOC could be used to increase the performance of noble metals to achieve catalysts effective for domestic applications.…”

Electrochemical promotion of propane oxidation on Pt deposited on a dense β″-Al2O3 ceramic Ag+ conductor

“…As reported in the literature (Vernoux et al, 2002; Bultel et al, 2004; Kokkofitis et al, 2005, 2007; Kotsionopoulos and Bebelis, 2007) propane and oxygen adsorb competitively on Pt catalyst surface and, as a result, a Langmuir–Hinshelwood type kinetic behavior is observed. Competitive adsorption of oxygen and propane strongly favors oxygen (Vernoux et al, 2002; Bultel et al, 2004; Kotsionopoulos and Bebelis, 2007).…”

Recent developments and trends in the electrochemical promotion of catalysis (EPOC)

“…On the other hand totally different behaviour can be observed during oxidation of saturated hydrocarbons like propane. Using various types of electrocatalysts (LSM/YSZ [46], Pt/YSZ [19,37,45,47], Rh/ YSZ [36,49], Pd/YSZ [65], Ag/YSZ [50], Pt/ b 00 -Al 2 O 3 (with Na ? conductivity) [48]) it has been found that the reaction exhibits purely electrophobic or in some cases (depending on the reaction conditions) inverted volcano behaviour.…”