title: Structure of the Active Platinum Cluster and Reaction Pathway of the Selective Synthesis of Phenol from Benzene and Oxygen Regulated with Ammonia on a Platinum Cluster/β-Zeolite Catalyst Studied by DFT Calculations.
abstract: DFT calculations were used to investigate the structure of the active Pt cluster and the catalytic reaction pathway for the selective synthesis of phenol from benzene and molecular oxygen regulated with ammonia on a Pt cluster/β-zeolite catalyst that was reported to be active for the selective hydroxylation of benzene only in the coexistence of ammonia. It was found that Pt5-Pt6 clusters were active for the direct synthesis of phenol, and they provided the reaction sites for bond rearrangements among ammonia, oxygen, and benzene; furthermore, the coexistence of ammonia was crucial for the selective oxidation of benzene to phenol, as it suppressed benzene combustion to CO2 and promoted the selective synthesis of phenol. It was further found that water coexisting in the system also played a significant role in desorbing phenol on the Pt cluster surface, which resulted in promotion of the overall selective synthesis of phenol. The energy diagram for the reaction sequences and the structures of the transition states were obtained, which indicated the origin of the Pt/β catalysis.
authors.affiliation: Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-8561, Japan. takehiko@k.u-tokyo.ac.jp.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Sasaki
authors.affiliation: Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Tada
authors.affiliation: Department of Engineering Science, The University of Electro-Communications, Chofu, Tokyo, 182-8585, Japan.
authors.forename: Linsheng
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Engineering Science, The University of Electro-Communications, Chofu, Tokyo, 182-8585, Japan.
authors.forename: Sachin
authors.initials: S
authors.lastname: Malwadkar
authors.affiliation: Department of Engineering Science, The University of Electro-Communications, Chofu, Tokyo, 182-8585, Japan.|Innovation Research Center for Fuel Cells, The University of Electro-Communications, Chofu, Tokyo, 182-8585, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Iwasawa
keywords: density functional theory; indispensable ammonia effect; oxidation; phenol synthesis; zeolites