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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: JamminMic on February 10, 2019, 12:34:55 PM

Title: Finding an Open Circuit Potential of a Hydrogen Pump Problem
Post by: JamminMic on February 10, 2019, 12:34:55 PM

My problem is:

"In an electrochemical H₂-pump using a proton conductive membrane (pH ≈ 0), H₂ can be compressed from low to high pressure. Assume an exchange current density of the HOR/HER on Pt of i₀ = 100 mA cm_{-2 Pt} with α_a = α_c (charge transfer coefficient) = 0.5, a H₂-partial pressure of 100 kPa on the low and 1000 kPa on the high pressure side. The system is operated at 80 °C and the roughness factor of the electrodes is 100 cm²_Pt cm^-2. The HFR (High Frequency Resistance) was determined to be 50 mΩ cm²."

"What is the thermodynamic open circuit potential between the two electrodes?"

I have tried using Butler-Volmer or a Tafel Slope equation in order to find the Overpotential but I'm not really getting anywhere. I'm also guessing that Nernst may be involved. Any suggestions?