The paper isn't about splitting water to yield hydrogen and oxygen gas which would be useful for energy applications. It's about a new way to make radical hydrogen (1 protein plus 1 electron) which is useful for synthesizing some organic compounds. It will be helpful for synthetic chemists and will make it easier to explore hydrogen radical chemistry. It may replace some processes that currently require transition metal catalysts, especially Samarium which is a rare earth element.
Anything that creates hydrogen radicals could conceivably be used to construct electricity-producing fuel cells.
Fuel cells normally radicalize hydrogen by contacting hydrogen with platinum catalysts under extreme conditions, requiring expensive and tricky design.
If this new process can do the same in mild conditions with inexpensive organic catalysts under exposure to light, it could lead to more economical fuel cell designs.
If I'm not mistaken this doesn't appear to be a catalyst. The reaction is driven by the irreversible formation of a strong P=O double bond, and the reagents are consumed. So great for chemical synthesis, but no clear path to fuel cell type reactions.
I did not look at the source paper before posting, but the paper makes it clear you're right.
However, the Wikipedia page titled "Phosphine Oxide" states that reduction of the oxide back to its original state is straightforwardly done with cheap reagents.
“In chemistry, a radical, also known as a free radical, is an atom, molecule, or ion that has at least one unpaired valence electron. With some exceptions, these unpaired electrons make radicals highly chemically reactive. Many radicals spontaneously dimerize. Most organic radicals have short lifetimes.”
