Recent Advances in the Heterogeneous Photocatalytic Hydroxylation of Benzene to Phenol

Abstract

Phenol is an important chemical material that is widely used in industry. Currently, phenol is dominantly produced by the well−known three−step cumene process, which suffers from severe drawbacks. Therefore, developing a green, sustainable, and economical strategy for the production of phenol directly from benzene is urgently needed. In recent years, the photocatalytic hydroxylation of benzene to phenol, which is economically feasible and could be performed under mild conditions, has attracted more attention, and development of highly efficient photocatalyst would be a key issue in this field. In this review, we systematically introduce the recent achievements of photocatalytic hydroxylation of benzene to phenol from 2015 to mid−2022, and various heterogeneous photocatalysts are comprehensively reviewed, including semiconductors, polyoxometalates (POMs), graphitic carbon nitride (g−C3N4), metal–organic frameworks (MOFs), carbon materials, and some other types of photocatalysts. Much effort is focused on the physical and chemical approaches for modification of these photocatalysts. The challenges and future promising directions for further enhancing the catalytic performances in photocatalytic hydroxylation of benzene are discussed in the end.

Recent trends in phenol synthesis by photocatalytic oxidation of benzene

“…13 Han et al reviewed heterogeneous photocatalytic hydroxylation of benzene to phenol since 2015. 23…”

“…13 Han et al reviewed heterogeneous photocatalytic hydroxylation of benzene to phenol since 2015. 23 In this perspective, we comprehensively and historically summarize the design of homogeneous and heterogeneous photocatalysts to oxidize benzene to phenol using H 2 O 2 or O 2 as an oxidant. Then, attention was turned to the most difficult and important issue in this research field: strategies to inhibit phenol overoxidation and increase phenol selectivity.…”

g-C3N4-modified Zr-Fc MOFs as a novel photocatalysis-self-Fenton system toward the direct hydroxylation of benzene to phenol

“…At present, it is mainly produced by the three-step isopropyl benzene process, which has serious limitations, such as dangerous intermediates and high energy consumption. 1 Therefore, a green, economic, and sustainable phenol production process is urgently needed. In recent years, the direct hydroxylation of benzene has attracted increasing attention.…”

Photo‐Activated Direct Catalytic Oxidation of Gaseous Benzene with a Cu‐Connected Serial Heterojunction Array of Co3O4/CuxO/Foam Cu Assembled via Layer upon Layer Oxidation

“…[ 6 ] As it is known, benzene is a stubborn six‐member conjugated structure molecule, which is essential construction unit of a large member of the aromatic VOCs. [ 7,8 ] Thus, to administer these VOCs, a treatment strategy of benzene with quick decomposition, completely mineralization, convenient operation is vitally required and it remains a huge challenge.…”

“…[6] As it is known, benzene is a stubborn six-member conjugated structure molecule, which is essential construction unit of a large member of the aromatic VOCs. [7,8] Thus, to administer these VOCs, a treatment strategy of benzene with quick decomposition, completely mineralization, convenient operation is vitally required and it remains a huge challenge.At present, many solutions have been extensively explored to decontaminate VOCs, such as adsorption/absorption, membrane separation, biodegradation, thermocatalytic oxidation, and photocatalytic degradation. [9][10][11][12][13] It is well known that thermocatalytic oxidation is a very efficient strategy to abate high concentration VOCs via destructing them into pieces with the help of heat energy.…”