Lecture 14 : Emphasis On Water Red-ox/ Splitting - Part 1
The photo-catalytic semiconductors are often used with addition of metals or with other hole trapping agents so that the life time of the excitons created can be increased.
This situation is to increase the life time of the excited electron and holes at suitable traps so that the recombination is effectively reduced.
In this mode, the positions of the energy bands of the semiconductor and that of the metal overlap appropriately and hence the alteration can be either way and also in this sense only the electrons are trapped at the metal sites and only reduction reaction is enhanced.