QUESTION 1 7 points Save Answer Photo electrochemical cells (PECs) are modeled a

Question

QUESTION 1 7 points Save Answer Photo electrochemical cells (PECs) are modeled after the photosynthetic systems found in plants. Photosynthesis allows plants to use sunlight as driving force to create what chemicals? oxygen and hydrogen oxygen and water Oxygen and NADPH ar and hydrogen QUESTION 2 7 points Save Answer The catalysts in the PEC perform what function? Convert the sunlight directly into electrical energy similar to a solar cel Catalyze the oxidation and reduction half reactions needed to decompose water into oxygen and hydrogen. Provide the heat needed to decompose water into oxygen and hydrogen. All of these are correct.

Explanation / Answer

1) Photosynthesis is a process whereby green plants utilize CO2 and water to produce energy and evolve oxygen. The process of photosynthesis occurs in two complex systems, known as PSI and PSII and produces two energy-rich compounds, ATP and NADPH.

Ans: Oxygen and NADPH

2) Semiconductors are usually used as catalysts in PCE. These semiconductors absorb light. Photons with energies greater than the semiconductor band gap are absorbed by the semiconductors and create electron-hole pairs and hence an electric field effect. This electric field splits water into hydrogen and oxygen. Hence, the second option is correct.

Ans: Catalyse the oxidation and reduction half reactions needed to decompose water into oxygen and hydrogen

3) Semiconductor catalysts must absorb a significant portion of sunlight to drive the splitting of water into oxygen and hydrogen. However, these catalysts have a large overpotential and hence cannot use a considerable portion of the solar spectrum. Moreover, they are prone to corrosion. These catalysts employ metals like Ti, Ga, etc. Hence, the last option is the correct answer.

Ans: All of the above

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