Thanks for the information about photocorossion.

Please make me clear that, is there is depletion of electrons in the semiconductor before the photocorossion. Since electrons are used for reduction reaction, is  there any chance for the usage of all electrons and thereby stops the reduction process.

As long as it is active or structurally intact

Dear Jolly

I am agree with Respected Abdul Sir.

There is no depletion of electrons in the semiconductor since photoproduced holes scavenge electrons by oxydation of species in the medium.

Thank you sir. 

Dear Jolly Antony 

Without any doubt, except high photocatalytic activity, stability of photocatalysts is practically important. Stability of a photocatalyst strictly depends on its composition, the preparation method, solution pH during the treatment, and …. . In the case of CdS, this photocatalyst rapidly inactivates due to its photo corrosion. If you want to work with such a photocatalyst, you should combine it with another semiconductor like TiO2 to increase its stability during the process.