Electrode processes at gas|salt|Pd nanoparticle|glassy carbon electrode contacts: salt effects on the oxidation of formic acid vapor and the oxidation of hydrogen

Abstract

The electrochemical oxidation of formic acid to CO 2 is facile at nano-palladium catalysts. In conventional electrochemical systems this process is conducted in aqueous phase and the resulting formation of poorly soluble CO 2 gas can limit the kinetics. Here, an alternative electrochemical system with the gas phase in closer contact to the palladium nanoparticle catalyst is investigated based on a glassy carbon electrode and a solid salt electrolyte. It is demonstrated that the reaction zone of salt (here (NH 4 ) 2 SO 4 is most effective), palladium nanoparticle catalyst, and gas phase, is where the electrochemical oxidation process occurs. The effects of the type of salt, the partial pressure of formic acid, and the gas flow rate are investigated. Preliminary data for the oxidation of hydrogen gas at the salt|palladium|electrode contact are reported. A significant salt effect on the palladium catalysed reactions is observed and potential future applications of ''salt cells'' in sensing are discussed.

Decamethylferrocene Redox Chemistry and Gold Nanowire Electrodeposition at Salt Crystal|Electrode|Nonpolar Organic Solvent Contacts

“…In recent reports the use of salt|electrode contact processes has been demonstrated for the case of salt surface immobilized redox systems, for palladium catalyst coated electrodes, and for textile-coated electrodes . In this study it is demonstrated that ammonium nitrate salt crystals can be used as a “thin film electrolyte phase” also in a nonpolar solvent such as hexane to electrically connect the working electrode and a counter-reference electrode (see Figure B).…”

Nano-Litre Proton/Hydrogen Titration in a Dual-Plate Platinum-Platinum Generator-Collector Electrode Micro-Trench

“…Recently it has been shown that fast hydrogen gas sensing could be achieved with electrochemical micro-sensors [28,29] or when utilizing a gas-salt-electrode contact triple phase boundary system [30]. A palladium catalyst was immobilized on a glassy carbon electrode surface and placed in contact to solid ammonium sulfate and hydrogen gas.…”