While studying photochemical hydrogen production in suspensions of ZnS
particles (with quantum yields reaching 90%), Reber and Meier found that the
most stable, long-lasting hydrogen production was observed when a mixture of
sodium sulfide and sodium hypophosphite was used as a hole scavenger [278].
This system appears to be very interesting in the evolutionary context. Here the
accumulation of disulfide ions (S2 2-) that could be caused by sulfide (S2-) oxidation
by photogenerated hole (h+) via a sulfide anion radical (S·-) as an intermediate
according to the equations