Photocatalysis on Selective Hydroxylation of Benzene to Phenol

Phenol is an essential precursor in the industrial world. A promising approach to producing phenol is through the use of photocatalysts. A photocatalyst possesses a significant band gap that can absorb photon energy and excite electrons in valence bands. These excited electrons are then employed to reduce oxidizing agents such as peroxide or water, producing hydroxyl radicals (•OH). These radicals can then oxidize benzene, converting it to phenol. A primary challenge in this process is the over-oxidation of phenol, which arises due to the reactivity of the OH group in its structure. Some strategies to counteract over-oxidation include adjusting the photocatalyst band gap, enhancing photocatalyst conductivity, and diminishing the hydrophilic characteristics of photocatalyst surfaces. This can be achieved by introducing materials like carbon, nitrogen, boron, metal, and organosilanes. This chapter will delve into potential photocatalyst materials suitable for the hydroxylation of benzene reactions to phenol, encompassing topics like material development, underlying mechanisms, methods to procure materials with high stability, activity, and selectivity toward phenol, as well as their applications.