One of the difference between metal oxide photocatalyst and non-metal photocatalyst is the effect of pH on the valence band. How does it affect and why?
Your question is not clear whether you are talking about during photocatalyst preparation or you are talking about photocatalyst in solution medium. As per my understanding, VB and CB change only if there is electronic redistribution occur and it occur mainly due to chemical interaction with other substances.
I am not sure what will happen to the band gap in different pH ,but some of the metal oxide might react with acids, lower pH, or with bases , high pH solutions. Therefore, these reactions of the metal oxides can affect thier band gap.
Edges of conduction and valence band of semiconductors are shifted towards higher energies in decreasing pH. For oxides, for example, it is 0,059 eV for 1 pH unit.
Anna Jakimińska Is that not the case for non-metal oxide semiconductors?
Kavya Bisaria
No - for other materials the value is different. For example - for sulfides it is around 0,033 eV.
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