# Predicting a route to use chloride as a reducing agent for titanium dioxide under UV

In my lab we are deadlocked on a seemingly simple problem. We would like to find some reaction where $\ce{Cl-}$ can be used as a reducing agent on $\ce{TiO2}$ in a UV photosynthesis. We ideally want a reaction like the following, but without using a metal

$\ce{Cl- + reactants -> products + e-}$

Then a hole in the TiO2 combines with the electron...

$\ce{TiO2+ + e- -> TiO2}$

As a secondary restriction, we need any extra reactants added to be unable to reduce $\ce{H2PtCl6}$.

What methods can be used to approach this problem, we are fairly certain something should work as its possible to do using ethylene glycol, but this can actually directly reduce the H2PtCl6. This seems like an issue very similar to metal half reactions, but we are unable to use any metals.