Engineers at Case Western Reserve University have made an electrochemical cell that uses a plasma for an electrode, instead of solid pieces of metal.
The technology may open new pathways for battery and fuel cell design and manufacturing, making hydrogen fuel and synthesizing nanomaterials and polymers.
A description of the research is now published in the online edition of the Journal of the American Chemical Society at http://pubs.acs.org/doi/abs/10.1021/ja207547b.
"Plasmas formed at ambient conditions are normally sparks which are uncontrolled, unstable and destructive," said Mohan Sankaran, a chemical engineering professor and senior author of the paper. "We've developed a plasma source that is stable at atmospheric pressure and room temperature which allows us to study and control the transfer of electrons across the interface of a plasma and an electrolyte solution."
Sankaran worked with former students Carolyn Richmonds and Brandon Bartling, current students Megan Witzke and Seung Whan Lee and fellow chemical engineering professors Jesse Wainright and Chung-Chiun Liu.
The group used a traditional set up with their nontraditional electrode.
They filled an electrochemical cell, essentially two glass jars joined with a glass tube, with an electrolyte solution of potassium ferricyanide and potassium chloride.
For the cathode, argon gas was pumped through a stainless steel tube that was placed a short distance above the solution. A microplasma formed between the tube and the surface.
The anode was a piece of silver/silver chloride.
When a current was passed through the plasma, electrons reduced ferricyanide to ferrocyanide.
Monitoring with ultraviolet-visible spectrophotometry showed the solution was reduced at a relatively constant rate and that each ferrycyanide molecule was reduced to one ferrocyan
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Case Western Reserve University