Summary: Electrochemical and Solid-State Letters, 2 (10) 519-521 (1999) 519
S1099-0062(99)06-042-3 CCC: $7.00 © The Electrochemical Society, Inc.
A Novel Fluorine Production Process in a Proton Exchange Membrane Reactor
Robert Lowrey,a,*,z Marc Doyle,b,** and Tim Andersona,**
aDepartment of Chemical Engineering, School of Engineering, University of Florida, Gainesville, Florida 32611, USA
bDuPont Central Research and Development, Experimental Station, Wilmington, Delaware 19880-0262, USA
Fluorine production was demonstrated in a Nafion 115 membrane-separated electrochemical reactor. Direct oxidation of anhydrous
HF from the gas-phase did not occur. Instead, the bifluoride ion (HF2
-) abundant in KF·xHF molten salt was a necessary reactant
for sustained fluorine evolution. Transport of bifluoride ion to catalyst-coated ELAT or membrane electrode assembly electrodes
was hindered by electrostatic exclusion from the perfluorinated ionomer solution catalyst binder and membrane. The anode was
flooded with KF·xHF molten salt to circumvent transport restrictions by providing HF2
- directly to the anode surfaces.
Galvanostatic operation at 0.5 kA/m2 yielded fluorine at 7.2 V with 62% current efficiency.
© 1999 The Electrochemical Society. S1099-0062(99)06-042-3. All rights reserved.
Manuscript submitted June 7, 1999; revised manuscript received June 21, 1999. Available electronically August 5, 1999.
A proton exchange membrane (PEM) reactor for electrolytic pro-
duction of fluorine was evaluated as a potential alternative to the
electrolyzers used for commercial fluorine production. This process
is similar in concept to the anhydrous HCl recycle process which uti-