Palladium nanoparticles deposited on a graphene-benzimidazole support as an efficient and recyclable catalyst for aqueous-phase Suzuki-Miyaura coupling reaction

Bimetallic (AuAg, AuPd and AgPd) nanoparticles supported on cellulose-based hydrogel for reusable catalysis

Biopolymer-derived hydrogels with low-cost and sustainable features have been considered as fascinating supported materials for metal nanoparticles. Cellulose, as the most abundant biopolymer, is a renewable raw material to prepare biopolymer-derived hydrogels for catalysis. Here, a cellulose-based hydrogel is designed to load bimetallic (AuAg, AuPd and AgPd) nanoparticles. 4-Nitrophenol reduction and Suzuki-Miyaura coupling reactions are selected to evaluate and compare the catalytic performance of the resulting bimetallic nanoparticle-loaded cellulose-based composite hydrogels. The bimetallic nanocomposite hydrogels are easy to be recycled over 10 times during the catalytic experiments and possess good applicability and generality for various substrates. The catalytic activity of bimetallic nanocomposite hydrogels was compared with recent literatures. In addition, the possible catalytic mechanism is also proposed. This work is expected to give a new insight for designing and preparing bimetallic nanoparticle-based cellulose hydrogels and proves its applicability and prospect in the catalytic field.

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.

Palladium decorated on a new dendritic complex with nitrogen ligation grafted to graphene oxide: fabrication, characterization, and catalytic application

Immobilized Pd nanoparticles on a new ligand, namely, tris(pentaethylene-pentamine)triazine supported on graphene oxide (Pdnp-TPEPTA(L)-GO) was introduced as a novel and robust heterogeneous catalyst for use in C-C bond formation reaction. The Pdnp-TPEPTA(L)-GO catalyst was synthesized by complexation of Pd with TPEPTA as a ligand with high N-ligation sites that were supported on graphene oxide through 3-chloropropyltrimethoxysilane. The prepared catalyst was characterized using some microscopic and spectroscopic techniques. The TPEPTA(L)-GO substrate is a 2D heterogeneous catalyst with a high specific surface area and a large amount of N-ligation sites. The Pdnp-TPEPTA(L)-GO catalyst used in the C-C bond formation reaction between aryl or heteroaryl and phenylboronic acid derivatives was applied towards the synthesis of biaryl units in high isolated yields. Notably, a series of competing experiments were performed to establish the selectivity trends of the presented method. Also, this catalyst system was reusable at least six times without a significant decrease in its catalytic activity.

Efficient reduction of nitroarenes in water catalyzed by reusable Pd nanoparticles immobilized on chitosan-functionalized graphene oxide

Graphene oxide was functionalized with chitosan for palladium immobilization (GO–Chit–Pd), which was used as an efficient catalyst for the reduction of aromatic nitro compounds using sodium borohydride in water. To achieve the best catalytic efficacy, various parameters such as temperature, solvent, mole ratio of hydrogen sources, and the amount of catalyst were optimized. The method has been applied to the reduction of a broad range of nitroarenes with different properties. The easy purification, convenient operation, environmental friendliness, and high product yields render this method viable for use. The nanocatalyst can be easily separated and efficiently recovered and reused for multiple cycles without appreciable loss in its catalytic activity.