Nano BEA zeolite catalysts for the selective catalytic cracking of n-dodecane to light olefins

Steam Catalytic Cracking of n-Dodecane to Light Olefins over Phosphorous- and Metal-Modified Nanozeolite Y

Nanozeolite Y was synthesized without a template and modified with phosphorous (P) and metals. P was introduced via impregnation with different weight loadings (0.5, 1, and 2 wt %), while ion exchange was developed to introduce zirconium (Zr) and cobalt (Co). The physicochemical properties of the catalysts were characterized with X-ray diffraction (XRD), N₂ adsorption-desorption, temperature-programmed desorption of ammonia (NH₃-TPD), and ²⁷Al and ³¹P solid-state nuclear magnetic resonance (NMR). The parent nanozeolite Y showed an identical XRD pattern to that of a previous study, and the modified nanozeolite Y showed a lower crystallinity. The introduction of P altered tetrahedral Al to an octahedral coordination, which affected the catalyst acidity. Then, the catalyst was evaluated to produce olefins from n-dodecane at 550, 575, and 600 °C. The conversion, gas yield, and olefin yield increased with increasing temperature. The maximum olefin yield (63%) was achieved with the introduction of 1 wt % P with the highest selectivity to ethylene. The Co-modified nanozeolite altered the zeolite structure and exhibited similar activity to the P-modified one. Meanwhile, Zr-modified nanozeolite Y caused excessive metal distribution, blocked the porous structure of the zeolite, and then reduced the catalytic activity.

Co-Doped Zeolite-GO Nanocomposite as a High-Performance ORR Catalyst for Sustainable Bioelectricity Generation in Air-Cathode Single-Chambered Microbial Fuel Cells

High-performance cobalt (Co) nanoparticles supported on a zeolite-graphene oxide (1:2) matrix (catalyst Z2) are synthesized through a facile reduction method. In multipoint Brunauer-Emmett-Teller (MBET) surface area analysis, catalyst Z2 demonstrates a higher surface area compared with other synthesized catalysts, indicating the presence of a larger number of catalytic active sites, and supports outstanding ORR performance due to an improved electron-transfer rate and a higher number of redox-active sites. Furthermore, it is observed that catalyst Z2 is an excellent electrocatalytic material due to its low charge-transfer resistance and higher oxygen reduction reaction (ORR) activity. Herein, the electrocatalytic investigation suggests that catalyst Z2 at a potential of 483 mV and a reduction current of -0.382 mA displays a higher electrocatalytic performance and higher stability toward ORR compared with other synthesized catalysts and even the standard Pt/C catalyst. Also, when catalyst Z2 is applied as an air-cathode ORR electrocatalyst for a single-chambered microbial fuel cell (SC-MFC), the SC-MFC coated with catalyst Z2 generates the maximum power density of 416.78 mW/m2, which is 306% higher than that of SC-MFC coated with Pt/C (102.67 mW/m2). In fact, the longer stability and electronic conductivity have contributed to an outstanding ORR activity of the nanocomposite due to its porous surface morphology and the presence of the functional groups in the zeolite-GO support matrix. In brief, Co (cobalt) nanoparticles doped on a zeolite-GO (1:2) support matrix are promising cathode electrocatalysts in the practical application of MFCs and other related devices.

Catalytic conversion of heavy naphtha to reformate over the phosphorus-ZSM-5 catalyst at a lower reforming temperature

Naphtha reforming to aromatics, naphthenes, and iso-paraffins is an essential process to increase the octane number of gasoline through the utilization of middle naphtha (whole). A ZSM-5 zeolite catalyst with modified medium pores was developed to comprehend the existing limitation of catalytic reforming to the unutilized refinery feedstock of heavy naphtha. The study applied a lower reforming conversion temperature (350 °C) than a conventional reformer without noble metal addition in an effort to lower the carbon footprint of the process and catalyst cost. The modified zeolite catalyst was impregnated with phosphorus oxide and spray-dried, followed by a hydrothermal treatment with steam. The parent and modified catalysts were characterized by NH₃-TPD, SEM, XRD, NMR, FTIR, and N₂ physisorption. Steam treatment was conducted to reduce the original zeolite acidity, mainly in the form of Brønsted acid sites, which resulted in the formation of phosphorus–aluminum species in the framework. The modified catalyst consisting of 40% ZSM-5 and 60% binder delivered high conversion of dodecane, and the reforming reaction selectivity favored the formation of carbonium ions through β-scission. Therefore, monomolecular cracking took place, resulting in the production of olefins and paraffin alongside iso-paraffins, aromatics, and naphthenes, which are associated with the bimolecular pathway. The reforming of heavy naphtha was different; the free radicals from β-scission were affected by the surrounding molecules of feedstock, and the bimolecular reactions were more dominant through zeolite pores. The study demonstrated that the addition of 10% steam during the reaction of heavy naphtha suppressed coke formation. Furthermore, high conversion and steady selectivity were maintained during the reaction, which resulted in gasoline reformate with a high research octane number (RON).

Catalytic conversion of heavy naphtha to reformate product over the phosphorus-ZSM-5 catalyst at a lower reforming temperature.

Naphtha catalytic cracking to olefins over zirconia–titania catalyst

A zirconia–titania-based catalyst was synthesized by a co-participation method to study the catalytic cracking of heavy naphtha (dodecane) into high value-added olefins.

Acidity modifications of nanozeolite-Y for enhanced selectivity to olefins from the steam catalytic cracking of dodecane

Nanozeolite Y for enhanced selectivity to olefins from dodecane cracking.

Mesoporogen-free synthesis of single-crystalline hierarchical beta zeolites for efficient catalytic reactions

Single-crystalline hierarchical Beta zeolites were synthesized by the l-lysine-assisted kinetic regulation method, exhibiting improved catalytic performance in both gas- and liquid-phase reactions.