Highly Efficient Phenol Hydrogenation to Cyclohexanone over Pd@CN-rGO in Aqueous Phase

Abstract

Selective hydrogenation of phenol is a green strategy to produce cyclohexanone. Achieving high phenol conversion and cyclohexanone selectivity under mild conditions is a significant challenge in the design and synthesis of highly efficient catalysts. Herein, a highly efficient Pd@CN-rGO catalyst is synthesized by supporting Pd nanoparticles on the composite of ZIF-derived N-doped carbon and reduced GO (CN-rGO), which is prepared via annealing the composite of layered ZIF-L-Co and GO.

Pd-Decorated Hierarchically Porous Carbon Nanofibers for Enhanced Selective Hydrogenation of Phenol

“…As shown in Figure S6, Pd@CNFs-0.1–0.2 decomposes quickly after 500 °C, confirming the assumption. Similar phenomena are also observed in literature. ,, …”

“…A broad CO 2 desorption peak is detected around 240 °C for each catalyst, which indicates the wide distribution of weak basic sites on the catalysts (Figure 6a). 30,52 The total amount of CO 2 adsorption on Pd@CNFs-0.1−y is not significantly different, and the different CO 2 desorption peak positions reflect the strength of the basic sites on the catalysts (Table S1). The basic site strength of the catalyst surface involves the content of ethertype oxygen.…”

“…Similar phenomena are also observed in literature. 22,30,52 The previous work found that the Co 2+ molar concentration in the mother solution of in situ growth of ZIFs signally influenced the microstructures of the Pd@CNF catalysts. 22 Therefore, the influence of the molar concentration of Co 2+ was also investigated in this work.…”

“…It means that the introduction of the active component Pd does not affect the crystal structure of materials, and the Pd content in the catalysts is low (<2 wt %) or the Pd dispersion is uniform. Besides, from the characterization of the defects on the catalyst surface (Figure S5a), it can be sniffed out that the initial oxygen concentration has no apparent effect on the surface defects of Pd@CNFs-0.1– y , and Pd@CNFs-0.1– y are all defect-rich materials ( I D / I G > 1) …”

Tailoring Locations and Electronic States of Rh Nanoparticles in KL Zeolite by Varying the Reduction Temperature for Selective Phenol Hydrogenation

“…The main challenging purpose of selective phenol hydrogenation is to attain high selectivity at elevated conversions without the compromise of reaction rate under mild catalytic conditions because the desired cyclohexanone product is prone to overhydrogenate to cyclohexanol. To this end, various parameters, such as the type − and surface properties , of the support and the type − and particle size , of the metal on the catalytic performance of selective phenol hydrogenation have been widely investigated. In general, among the active metals, palladium catalysts exhibit relatively good selectivity of cyclohexanone although the intrinsically low activity needs to be improved.…”