Photocatalysis: Fundamentals and Perspectives
CHAPTER 2: Understanding the Chemistry of Photocatalytic Processes
Published:17 Mar 2016
Amer Hakki, Jenny Schneider, Detlef Bahnemann, 2016. "Understanding the Chemistry of Photocatalytic Processes", Photocatalysis: Fundamentals and Perspectives, Jenny Schneider, Detlef Bahnemann, Jinhua Ye, Gianluca Li Puma, Dionysios D Dionysiou, Jenny Schneider, Detlef Bahnemann, Jinhua Ye, Gianluca Li Puma, Dionysios D Dionysiou
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The attainable oxidation and reduction half-reactions that can be achieved on the surface of a given semiconductor photocatalyst are limited by the positions of the band edges of the photocatalyst.1
It is well known that different semiconductors may have significantly different conduction and valence band edges. The potential of these edges will determine the thermodynamic feasibility of the reactions that can proceed. Figure 2.1 shows the CB and VB potentials of various semiconductors.
In this respect, it is essential to take into account the reduction potentials (E) of the substrate, as well as those of the intermediates that are formed during the photocatalytic reaction(s). However, the reduction potentials for different organic or inorganic compounds are usually dependent on the reaction conditions such as pH and the employed electrolyte. The reduction potential of the couples M/M˙− refer to reactions described by eqn (2.1) and (2.2):