Chapter 3, Problem 3.15P

Solar Chemical Energy Storage. The major ways to utilize, capture, or store the sun’s energy are solar thermal (see P8-16_B), solar voltaic, biomass conversion, solar water splitting (P10-13_B), and solar chemical. Solar chemical refers to processes that harness and store solar energy by adsorbing light in a reversible chemical reaction; see http://en.wikipedia.org/wiki/Solar_chemical. For example, the photodimerization of anthracene absorbs and stores solar energy that can be released when the reverse reaction takes place.

Figure P3-15.1 Anthracene dimerization.

Another reaction of interest is the Norbornadiene–Quadricyclane (NQ) couple, where solar energy is adsorbed and stored in one direction and released in the other.

Figure P3-15.2 The Norbornadiene–Quadricyclane (NQ) couple is of potential interest for sunlight energy storage.

1. (a) Suggest a rate law for the reversible photodimerization of anthracene.
2. (b) Suggest a rate law for the reversible storage of energy by the NQ couple.