Alkaline Water Electrolysis with RbOH

Question

In industry, it appears the alkaline water electrolysis is largely done with solutions of NaOH or KOH - presumably due to low cost.

I presume that alkaline water electrolysis is possible under RbOH, however, I can not seem to find any evidence in the literature showing the use of RbOH for water electrolysis. Can water electrolysis be done with RbOH to give oxygen and hydrogen gas evolution at the working (TiO2) and counter (Pt) electrode respectively?

Thanks!

Answer 1

Of course! Rb is more electropositive than hydrogen, so hydrogen is released.

As you mention, $\ce{RbOH}$ is a bit more expensive than $\ce{NaOH}$. At present, $\ce{RbOH}$ is ~US\$500/kg and $\ce{NaOH}$ is ~US\$500/tonne, three orders of magnitude cheaper.

You might use $\ce{CsOH}$ or $\ce{FrOH}$, too. The Fr will even illuminate the reaction with Cherenkov radiation.