Tunable isoparaffin and olefin yields in Fischer–Tropsch synthesis achieved by a novel iron-based micro-capsule catalyst

Insights into the Diffusion Behaviors of Water over Hydrophilic/Hydrophobic Catalysts During the Conversion of Syngas to High-Quality Gasoline

Although considerable efforts towards directly converting syngas to liquid fuels through Fischer-Tropsch synthesis have been made, developing catalysts with low CO2 selectivity for the synthesis of high-quality gasoline remains a big challenge. Herein, we designed a bifunctional catalyst composed of hydrophobic FeNa@Si-c and HZSM-5 zeolite, which exhibited a low CO2 selectivity of 14.3 % at 49.8 % CO conversion, with a high selectivity of 62.5 % for gasoline in total products. Molecular dynamic simulations and model experiments revealed that the diffusion of water molecules through hydrophilic catalyst was bidirectional, while the diffusion through hydrophobic catalyst was unidirectional, which were crucial to tune the water-gas shift reaction and control CO2 formation. This work provides a new fundamental understanding about the function of hydrophobic modification of catalysts in syngas conversion.

Macroscopic assembly style of catalysts significantly determining their efficiency for converting CO2 to gasoline

Efficient conversion of CO₂ into high-quality gasoline is realized over a Fe–Zn–Zr and HZSM-5 core–shell catalyst.

Synthesis of Engineered Zeolitic Materials: From Classical Zeolites to Hierarchical Core-Shell Materials

The term "engineered zeolitic materials" refers to a class of materials with a rationally designed pore system and active-sites distribution. They are primarily made of crystalline microporous zeolites as the main building blocks, which can be accompanied by other secondary components to form composite materials. These materials are of potential importance in many industrial fields like catalysis or selective adsorption. Herein, critical aspects related to the synthesis and modification of such materials are discussed. The first section provides a short introduction on classical zeolite structures and properties, and their conventional synthesis methods. Then, the motivating rationale behind the growing demand for structural alteration of these zeolitic materials is discussed, with an emphasis on the ongoing struggles regarding mass-transfer issues. The state-of-the-art techniques that are currently available for overcoming these hurdles are reviewed. Following this, the focus is set on core-shell composites as one of the promising pathways toward the creation of a new generation of highly versatile and efficient engineered zeolitic substances. The synthesis approaches developed thus far to make zeolitic core-shell materials and their analogues, yolk-shell, and hollow materials, are also examined and summarized. Finally, the last section concisely reviews the performance of novel core-shell, yolk-shell, and hollow zeolitic materials for some important industrial applications.

Design and Synthesis of Powerful Capsule Catalysts Aimed at Applications in C1 Chemistry and Biomass Conversion

Tandem catalytic reaction is a promising strategy to improve the utilization efficiency of energy and resources. The conventional hybrid catalysts cannot readily realize the precisely controlled synthesis of target products due to the unrestricted, open reaction environment. Assembling the hybrid catalyst with multiple active sites into core-shell structured capsule catalyst is one of the most effective ways to enhance the selectivity of desired products during a tandem catalysis process, because the core-shell structure offers a space-confined reaction field and synergistic effect. This review describes our recent progresses on the design and synthesis of core-shell structured zeolite capsule catalysts developed for C1 chemistry and biomass conversion. The various synthesis methods for constructing the well-defined zeolite capsule catalysts are described in detail. The applications of the capsule catalysts in catalysis, including the middle isoparaffins synthesis from syngas, one-step synthesis of dimethyl ether, and liquid-phase tandem reaction of glycerol conversion, are discussed, respectively. Our perspectives regarding the challenges and opportunities for future research in the field are also provided.

Synthesis of isoalkanes over a core (Fe–Zn–Zr)–shell (zeolite) catalyst by CO2 hydrogenation

An Fe–Zn–Zr@zeolite core–shell catalyst synthesized by a simple cladding method shows an obvious confinement effect on the synthesis of isoalkanes by CO₂ hydrogenation.