Design and fabrication of PdO/CexOy composite catalysts with coaxial nanotuber and studies of their synergistic performance in Suzuki-Miyaura reactions

Boosting Suzuki coupling reaction via pore expanding and palladium-zinc alloying

A palladium-zinc alloy nanoparticles decorated nitrogen-doped porous carbon catalyst (PdZn30-NC) was synthesized and utilized for Suzuki coupling reaction. The alloying palladium (Pd) with zinc (Zn) and pore expanding are realized simultaneously. Density functional theory (DFT) calculations and experimental studies reveal that the alloying Pd with Zn can lower the energy barrier in Suzuki coupling reaction. Nitrogen adsorption-desorption measurements uncover that pore expansion caused by the zinc nitrate hexahydrate assisted calcination gives rise to the multiplication of mesopore with a pore diameter of 6 nm, which facilitates mass transfer during the reaction. As a result, the alloying Pd with Zn and pore expanding together endow PdZn30-NC with excellent catalytic activity. PdZn30-NC demonstrates exceptional catalytic activity and stability in Suzuki coupling reaction. A high biphenyl yield of 97.7 % within 40 min and stable reusability of 93.3 % yield after five reuse cycles can be achieved. This work not only offers a viable method for Suzuki coupling reaction, but also provides insights for designing new catalysts toward Suzuki coupling reaction.

Robust C-PdNi-CNF Sandwich-Structured Catalyst for Suzuki Reactions and Experimental Study on the Mechanism

The stability of metal nanoparticles is one of the key issues for their catalytic applications. In this study, we fabricated a sandwich structure to protect the metal nanoparticles. A carbon layer was used to wrap the PdNi nanoparticles on the carbon fiber, and the whole preparation process was simple and green. Electron transfer occurs between the carbon layer and the metal nanoparticles, making the two more closely combined. As a catalyst for the Suzuki reaction, it exhibits highly efficient catalysis and excellent stability. The calculated TOF reaches 18 662 h^-1. After nine cycles, there was almost no decrease in performance. Additionally, we found that the addition of iodobenzene into the chlorobenzene reaction system could significantly improve the chlorobenzene conversion, and we proved that the catalyst has fine activity and stability with a bright future in commercial applications. The possible catalytic mechanism of Suzuki reaction was proposed based on experimental results. This study provides a simple and green method to prepare encapsulated metal nanoparticle catalysts and gives a deep insight into Suzuki reaction.

Enhancement of the catalytic activity of Suzuki coupling reactions by reduction of modified carriers and promotion of Pd/H2-PrxOy surface electron transfer

Pd/H2-PrxOy nanotubes were prepared by electrostatic spinning, high-temperature calcination and modified deposition–precipitation method, and exhibited high catalytic performance for Suzuki coupling reaction under mild conditions.

New Palladium - ZrO2 Nano-Architectures from Thermal Transformation of UiO-66-NH2 for Carbonylative Suzuki and Hydrogenation Reactions

The new nanocomposites, Pd/C/ZrO₂ , PdO/ZrO_2, and Pd/PdO/ZrO₂ , were prepared by thermal conversion of Pd@UiO-66-Zr-NH₂ (MOF) in nitrogen or air atmosphere. The presence of Pd nanoparticles, uniformly distributed on the ZrO₂ or C/ZrO₂ matrix, was evidenced by transmission electron microscopy, scanning electron microscopy (SEM), Raman and X-ray Photoelectron Spectroscopy (XPS) methods. All pyrolysed composites retained the shape of the MOF template. They catalyze carbonylative Suzuki coupling under 1 atm CO with an efficiency significantly higher than the original Pd@UiO-66-Zr-NH₂ . The most active PdO/ZrO₂ composite, formed benzophenone with TOF up to 1600 h^-1 , while by using Pd@UiO-66-Zr-NH₂ , much lower TOF values, 51-95 h^-1 , were achieved. After the reaction, PdO/ZrO₂ was recovered with the same composition and catalytic activity. Very good results were also obtained in the transfer hydrogenation of benzophenones to alcohols with Pd/C/ZrO₂ and PdO/ZrO₂ catalysts under microwave irradiation.

Recent Progress of Metal Nanoparticle Catalysts for C–C Bond Forming Reactions

Over the past few decades, the use of transition metal nanoparticles (NPs) in catalysis has attracted much attention and their use in C–C bond forming reactions constitutes one of their most important applications. A huge variety of metal NPs, which have showed high catalytic activity for C–C bond forming reactions, have been developed up to now. Many kinds of stabilizers, such as inorganic materials, magnetically recoverable materials, porous materials, organic–inorganic composites, carbon materials, polymers, and surfactants have been utilized to develop metal NPs catalysts. This review classified and outlined the categories of metal NPs by the type of support.

A Hierarchical-Structured Impeller with Engineered Pd Nanoparticles Catalyzing Suzuki Coupling Reactions for High-Purity Biphenyl

Suzuki cross-coupling reactions catalyzed by palladium are authoritative protocols in fine-chemical synthesis. Mass transfer and catalyst activity are both significant factors affecting the reaction efficiency in heterogeneous reactions. Although the holistic catalysts hold great promise in heterogeneous reactions due to the enhanced mass transport and convenient recycling, the unsatisfied catalytic activity has impeded further large-scale applications. In addition, another pronounced barrier is the product separation in the intricate system. Here, the catalytic production and separation of biphenyl (purity of 99.7%) were achieved by integrating the Suzuki cross-coupling reactions and the crystallization separation for the first time. A hierarchical-structured impeller with Pd nanoparticles (NPs) loaded on the Ni(OH)₂ nanosheets was prepared to catalyze the Suzuki reactions for bromobenzene, which exhibits a high turnover frequency (TOF) value of 25,976 h^-1 and a yield of 99.5%. The X-ray absorption fine structure (XAFS) analysis has unveiled that the electron transfer between the Pd NPs and Ni(OH)₂ accounts for the greatly enhanced catalytic activity. The findings inspire new insights toward rational engineering of highly efficient holistic catalysts for Suzuki reaction, and the innovative integrated technology offers an avenue for the separation and collection of products.

An effective photothermal dual-responsive Pd1Cu4/CexOy catalyst for Suzuki–Miyaura coupling reactions under mild conditions

A Pd₁Cu₄/Ce_xO_y catalyst can efficiently catalyze Suzuki reactions under both heating and visible light irradiation conditions.