NANO230
North Seattle Community College
Homework #3
Due:_______________________
Solar-Driven Water Splitting
Read through the Lab Manual: Discovering New Materials for Solar-Driven Water Splitting.
Answer the following on a separate page.
1. What is the chemical equation that describes water splitting? What can the products of this
reaction be used for? In what ways is water splitting advantageous compared to photovoltaics?
2. What are the chemical equations for the half reactions? Indicate which half reaction is the
oxidation of water, and which half reaction is the reduction of H+ to H2. Indicate which half
reaction occurs at the carbon counter electrode, and which half reaction occurs at the metal
oxide spot.
3. How much potential (voltage) is required to drive the water splitting reaction? What
wavelength range (in nm) and colors of the solar spectrum has the energy necessary to split
water? [Hint: consider the potential in eV and convert to nm)
4. Refer to Figure 5 in the Lab Manual, which shows band gaps and band energies. Is silicon a
good material for water splitting? Give two specific reasons to support your argument.