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Arno Smets, Wilson Smith, Paula Perez Rodriguez
Third Generation PV and Other Ways to Utilize Solar Energy Solar - - PowerPoint PPT Presentation
Third Generation PV and Other Ways to Utilize Solar Energy Solar - - PowerPoint PPT Presentation
Third Generation PV and Other Ways to Utilize Solar Energy Solar Fuels Week 6.3 Arno Smets, Wilson Smith, Paula Perez Rodriguez Electricity Heat Solar Fuels Ragone Plot: Energy vs Power Density Fuel Energy Energy [kJ/g] [kJ/l] Coal
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Ragone Plot: Energy vs Power Density
Source: “Indication of anomalous heat energy production in a reactor device containing loaded nickel powder”. Levi et al. 2013
Fuel Energy [kJ/g] Energy [kJ/l] Coal 29.3
- Wood
14.6
- Gasoline
43.5 30590 Diesel 42.7 29890 Natural Gas 50.02 31.7 Hydrogen 119.9 10
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Can we learn from Nature?
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Hydrogen cycle
CO2 CO H2 O2 H2O CH4
Water Gas Shift Fisher-Tropsh Combustion Electrolysis
Energy Energy Energy Energy
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Direct photoelectrolysis
Cathodic: 2H++2e- H2 Anodic: 2H2O O2+4H++4e- TOTAL: H2O H2 + ½ O2
Potential: 1.23 V
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Band bending
N-type semiconductor: Anode P-type semiconductor: Cathode
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Challenges for photoelectrochemistry
- 1. Absorption
- 2. Separation of charges
- 3. Catalysis
1 2 3 3
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Materials for photoelectrodes
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Improving photoelectrode efficiency
0.5 1.0 1.5 2.0 2 4 BiVO4 +Gradient doped +Catalyst
j (mA/cm
2)
V vs. RHE (V)
BiVO4 BiVO4 + Catalyst dark 0.5 1.0 1.5 2.0 2 4
j (mA/cm
2)
V vs. RHE (V)
BiVO4 dark 0.5 1.0 1.5 2.0 2 4
j (mA/cm
2)
V vs. RHE (V)
BiVO4 BiVO4 + Catalyst dark
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Potential of the reaction
Reaction potential 1.23V Overpotential 0.8V
Needed voltage for the reaction to happen
Photoelectrode 0.6V Solar cell 1.5V
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Hybrid photoelectrode
Photoelectrode Solar cell Counter electrode
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Jsc
Voc
Current Potential
Hybrid photoelectrode
Jsc
Voc
Current Potential Jphoto Voperational
𝜃𝑇𝑈𝐼 = 𝐾𝑞ℎ𝑝𝑢𝑝 ⋅ 1.23𝑊 𝑄
Solar cell Photoanode
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MECS PV-PEC Device
4.9% Solar to Hydrogen Conversion Efficiency!
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