Hierarchical NiZn Solid Solution as a Highly Efficient Palladium Free Heterogeneous Catalyst for Suzuki-Miyaura Cross-Coupling Reaction

Ni/PiNe Heterogeneous Catalyst from Biomass Waste: Low-Loading, Ligand-Free Suzuki-Miyaura Cross-Coupling

An efficient Ni-based heterogeneous catalyst from pine needles urban waste valorization was designed and developed with a resource recycling strategy. The Ni/PiNe catalyst was fully characterized and tested in the Suzuki-Miyaura coupling under microwave irradiation. Although Ni is a promising candidate for replacing Pd-based catalytic systems, it generally requires a high catalyst amount and the exploitation of ligands and additives to enhance the reaction rate. On the contrary, with our new Ni/PiNe, 30 different products were efficiently synthesized with an isolated yield of up to 93 %, using a very low catalyst amount and in the absence of ligands. Furthermore, the Ni/PiNe catalyst also showed good durability for consecutive cycles and an impressive TON value (1140). In addition to the catalytic efficiency in short reaction time and to the stability and durability under MW irradiation, the Ni/PiNe allowed for further optimization, achieving a low E-factor value (14.0), thus highlighting the potential in further reducing the waste and costs associated to the process.

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.

Chitosan-derived mesoporous N-doped carbon catalyst embedded with NiO for highly selective benzyl alcohol oxidation

MOF-derived heteroatom-doped mesoporous carbons have gained the significant consideration in heterogenous catalytic reactions because of their multipurpose features. Especially, the high Specific Surface Area (SSA) of these materials provides abundant activated sites for the catalytic reactions, while the mesoporous structure allows for the effective mass transfer, enhancing the overall capability of the catalytic process. Herein, the efficient NiO/CN-T (T referred to the pyrolysis temperature) was prepared by facile pyrolysis of MOF/CS composite (Ni-MOF (74), Chitosan) in the presence of excess amount of starch as the carbon precursor. The NiO/CN-T as heterogenous catalyst has desired SSA varied from 1094 to 491 m2.g-1. The optimized catalyst (NiO/CN-600) possesses the superior catalytic activity toward the oxidation of the BnOHs due to its high SSA (1094 m2.g-1), which can notably rectify the mass transfer proficiency. Additionally, the NiO/CN-600 heterogenous catalyst also represents the acceptable chemical stability. So, it was demonstrated that such an innovative strategy can provide several versatile tunability insights for the preparation of MOF/biopolymer-derived heterogenous catalysts.