Phase 3: Embedded and Potential Natural Gas-Fired Electric ...
1 Intro and Phase Potential
-
Upload
ali-arshad -
Category
Documents
-
view
219 -
download
0
Transcript of 1 Intro and Phase Potential
![Page 1: 1 Intro and Phase Potential](https://reader031.fdocuments.us/reader031/viewer/2022021200/577d239a1a28ab4e1e9a413a/html5/thumbnails/1.jpg)
8/3/2019 1 Intro and Phase Potential
http://slidepdf.com/reader/full/1-intro-and-phase-potential 1/11
1- 11- 1
heterogeneous electron transfer:Idealized
actual:
P= physisorbed impurity
e-
e-
Eapplied
counter electrode
Ox + n e- Red
Ox
Red
e-
k o
k o
![Page 2: 1 Intro and Phase Potential](https://reader031.fdocuments.us/reader031/viewer/2022021200/577d239a1a28ab4e1e9a413a/html5/thumbnails/2.jpg)
8/3/2019 1 Intro and Phase Potential
http://slidepdf.com/reader/full/1-intro-and-phase-potential 2/11
1- 21- 2
Special Features of Electrochemistry
• analytical sensitivity (1 pamp = 10-17 moles/second)
• can make microscopic probes ( < 1 um)
• wide range of time scales ( ~50 nsec up)
• large, tunable driving force
• direct interconversion of chemical and electrical energy(not a heat engine, not Carnot limited)
![Page 3: 1 Intro and Phase Potential](https://reader031.fdocuments.us/reader031/viewer/2022021200/577d239a1a28ab4e1e9a413a/html5/thumbnails/3.jpg)
8/3/2019 1 Intro and Phase Potential
http://slidepdf.com/reader/full/1-intro-and-phase-potential 3/11
1- 31- 3
2 um
Ewing, Strein, Lau, Acc. Chem. Res. 1992, 25, 440
carbon microelectrodes
single-cell voltammogram,matching that of noradrenaline
amperometric response fromsingle adrenal chromaffin cell
![Page 4: 1 Intro and Phase Potential](https://reader031.fdocuments.us/reader031/viewer/2022021200/577d239a1a28ab4e1e9a413a/html5/thumbnails/4.jpg)
8/3/2019 1 Intro and Phase Potential
http://slidepdf.com/reader/full/1-intro-and-phase-potential 4/11
1- 41- 4
Special Features of Electrochemistry
• analytical sensitivity (1 pamp = 10-17 moles/second)
• can make microscopic probes ( < 1 um)
• wide range of time scales ( ~50 nsec up)
• large, tunable driving force(Cl2, Na, F2 production, fast reactions, electrosynthesis)
• direct interconversion of chemical and electrical energy(not a heat engine, not Carnot limited)
![Page 5: 1 Intro and Phase Potential](https://reader031.fdocuments.us/reader031/viewer/2022021200/577d239a1a28ab4e1e9a413a/html5/thumbnails/5.jpg)
8/3/2019 1 Intro and Phase Potential
http://slidepdf.com/reader/full/1-intro-and-phase-potential 5/11
1- 51- 5
air H2
H2O(exhaust)
e- load
polymer electrolyte membrane, catalysis, support,(all of the important stuff)
gas flow channels
recirculated fuel
(~ 200 amps, 0.5 volt)
heat, ~ 85 oC
![Page 6: 1 Intro and Phase Potential](https://reader031.fdocuments.us/reader031/viewer/2022021200/577d239a1a28ab4e1e9a413a/html5/thumbnails/6.jpg)
8/3/2019 1 Intro and Phase Potential
http://slidepdf.com/reader/full/1-intro-and-phase-potential 6/11
1- 61- 6
Fuel cell powered bus, Ballard Power Systems, 1997
![Page 7: 1 Intro and Phase Potential](https://reader031.fdocuments.us/reader031/viewer/2022021200/577d239a1a28ab4e1e9a413a/html5/thumbnails/7.jpg)
8/3/2019 1 Intro and Phase Potential
http://slidepdf.com/reader/full/1-intro-and-phase-potential 7/111- 71- 7
Ballard Fuel Cell + electric motor, 275 hp (205 kW)
![Page 8: 1 Intro and Phase Potential](https://reader031.fdocuments.us/reader031/viewer/2022021200/577d239a1a28ab4e1e9a413a/html5/thumbnails/8.jpg)
8/3/2019 1 Intro and Phase Potential
http://slidepdf.com/reader/full/1-intro-and-phase-potential 8/111- 81- 8
Who cares about electrode kinetics?
• electrosynthesis(Al, Mg, NaOH, Cl2, etc)
• electrochemical energy
conversion (fuel cells,batteries, photocells)
• electroanalysis (glucose,
O2, K+,
pH, etc.)
• corrosion(almost everything)
≈ $ 40 billion/yr of U.S. GDP
≈ $ 80-200 billion/yr in U.S.A.
![Page 9: 1 Intro and Phase Potential](https://reader031.fdocuments.us/reader031/viewer/2022021200/577d239a1a28ab4e1e9a413a/html5/thumbnails/9.jpg)
8/3/2019 1 Intro and Phase Potential
http://slidepdf.com/reader/full/1-intro-and-phase-potential 9/111- 91- 9
The Big Issues:
1. Thermodynamics of electrochemical cells
(how does an electron affect free energy, etc.?)
2. Kinetics of electron transfer
(what happens when an electron is a reagent?)
3. Mass transport
(things have to get to the electrode to react)
![Page 10: 1 Intro and Phase Potential](https://reader031.fdocuments.us/reader031/viewer/2022021200/577d239a1a28ab4e1e9a413a/html5/thumbnails/10.jpg)
8/3/2019 1 Intro and Phase Potential
http://slidepdf.com/reader/full/1-intro-and-phase-potential 10/111- 101- 10
-6.0
-5.5
-5.0
-4.5
-4.0
-3.5
-3.0
-0.1 0.1 0.3 0.5 0.7 0.9 1.1
Ener gyr elativetovacuum,
eV
f(E)
Fermi distribution function
Cu, Ef = -4.65 V
-6.0
-5.5
-5.0
-4.5
-4.0
-3.5
-3.0
-0.1 0.1 0.3 0.5 0.7 0.9 1.1
Ener gyr elativetovacuum,
eV
f(E)
Fermi distribution function
Pt, Ef = -5.70 V
Cu and Pt, both 298 K
![Page 11: 1 Intro and Phase Potential](https://reader031.fdocuments.us/reader031/viewer/2022021200/577d239a1a28ab4e1e9a413a/html5/thumbnails/11.jpg)
8/3/2019 1 Intro and Phase Potential
http://slidepdf.com/reader/full/1-intro-and-phase-potential 11/111- 111- 11
µ K +
= µ K +
o+ RT ln a + Fφ
K +
K in+
K out+
φin
φout
K + permeable membrane
electrostatic potentialK + activity
µ K +
a
a