Transformation of CO2 to Carbon Nanotubes by Catalytic Chemical Vapor Deposition using a Metal-Supported Hierarchical Zeolite Template.

The conversion of CO2 into valuable substances is a topic of great interest in current research. Carbon nanotubes (CNT) have emerged as highly promising materials for CO2 conversion. In this study, we successfully developed a catalyst by loading active transition metals (Fe or Ni) onto hierarchical zeolite for CNT synthesis. Our catalyst demonstrated excellent performance under synthetic conditions. The most favorable CNT was obtained using the 25 wt.% FeHieFAU catalyst, which exhibited a diameter size of 23.1 nm, a CNT yield of 15.4 %, and an ID /IG ratio of 0.56, indicating high quality. Additionally, we investigated the beneficial effects of the synthesized CNT by testing their current response. Notably, the current response of the synthesized CNT surpassed that of commercial CNT when using a 0.5 M H2 SO4 supporting electrolyte and cyclic voltammetry (V vs. Ag/AgCl). These findings highlight the significant contributions of the small diameter and superior quality of our synthesized pure CNT, which offer potential improvements in current response compared to commercial CNT. This research opens new avenues for utilizing CNT in CO2 conversion and electrochemical applications.

Binder-free hierarchical zeolite pellets and monoliths derived from ZSM-5@LDHs composites for bioethanol dehydration to ethylene.

The development of industrial catalysts is of crucial importance for practical uses. However, the use of extruded catalysts in industry is still limited because of a remarkably decreased catalytic activity when combining them with binders. This contribution illustrates the rational design of binder-free hierarchical ZSM-5 pellets and monoliths derived from zeolite@LDHs composites via extrusion and 3D printing technologies, respectively. The designed catalyst applied in bioethanol dehydration boosts the ethylene yield by over 93.4 ± 2.2% due to the synergistic effect of zeolites and LDHs.

Synthesis and Characterization of Sn, Ge, and Zr Isomorphous Substituted MFI Nanosheets for Glucose Isomerization to Fructose.

Various metals including Sn, Ge, and Zr have been successfully incorporated into the MFI nanosheets via a one-pot synthesis. The as-synthesized zeolites exhibit high external surface area and mesopore volume without large metal oxides aggregated on zeolite surfaces. Interestingly, the successful introduction of heteroatoms in MFI nanosheets can be confirmed by shifted XRD peaks corresponding to the unit cell expansion due to the replacement of metals into the framework. In addition, the UV-Vis absorbance spectra reveal that at the suitable metal loading the incorporated tetrahedral coordination of metal species in the zeolite framework has been obtained. To illustrate the benefits of the prepared catalysts, the glucose isomerization to fructose was carried out in a water/dioxane system. Obviously, the SnMFI-NS samples, containing the high dispersion of metal isomorphous species demonstrate the outstanding catalytic behavior in term of fructose selectivity (>85 %).

Synthesis and Characterization of Sn, Ge, and Zr Isomorphous Substituted MFI Nanosheets for Glucose Isomerization to Fructose.

Invited for a cover feature this month is the research group of Asst. Prof. Dr. Chularat Wattanakit from School of Energy Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Thailand. The cover picture shows the facile synthesis of Sn, Ge, and Zr isomorphously substituted MFI with hierarchical structures by a one-pot hydrothermal process. These designed materials illustrate the promising catalytic performance in glucose isomerization to fructose. More information can be found in the Full Paper by Chularat Wattanakit, and co-workers.

Fine-tuning the chemical state and acidity of ceria incorporated in hierarchical zeolites for ethanol dehydration.

The chemical state and acidity of ceria incorporated in hierarchical zeolites have been successfully tuned due to the presence of hierarchical structures of zeolite nanosheets and interaction between ceria and zeolite supports with different Si/Al ratios. The Ce reactivity of the designed materials for ethanol dehydration is remarkably improved due to the improvement of the metal-support interaction, acidity, and reducibility of Ce species, eventually facilitating an unprecedented yield of ethylene close to 100%. This finding opens up a new perspective for the development of ceria based hierarchical zeolite catalysts for ethanol dehydration applications.