(Co/Zn) Al2O4 nano catalyst for waste cooking oil catalytic cracking

The current work investigated the preparation of Nano-particles of Co/Zn Al₂O₄ as a catalyst via co-precipitation method. Several analyses, including BET, XRD, HRTEM, EDX, SEM, and FTIR, were used to characterize it. The analysis revealed that the prepared catalyst had an average surface area of 69.20 m²/g, a cross-sectional area of 16.2 m²/molecule, an average particle size of approximately 28 nm, and a pore size of 0.22 cm³/g. The prepared catalyst was used in a bio fuel synthesis process via thermo-catalytic cracking of waste cooking oil (WCO) in a single step batch reactor. Catalyst loading was tested with different weight percentage of 1.5%, 2%, and 2.5%. The pilot study revealed that the best conditions for optimizing bio jet fuel yield were 400 °C, a catalyst loading of 2%, and a reaction time of 30 min.The optimal cut-off from the distillation process of crude liquid bio fuel product which represents a fraction of bio-jet fuel was in the range from 150 to 240 °C.

Synthesis of mesoporous Pt@SAPO-11 via in situ encapsulation for the decarboxylation of oleic acid to prepare C8–C17 alkanes

The 1.0 wt% Pt@SAPO-11 catalyst was prepared by an in situ encapsulation method and used to catalyze the decarboxylation of oleic acid to C8–C17 alkanes. A reaction yield of 80.8% was achieved after 4 h at 340 °C.

Fabrication of sea urchin-like hierarchical porous SAPO-11 molecular sieves toward hydrogenation of lipid to jet fuel

Novel sea urchin-like hierarchical porous SAPO-11 molecular sieves were fabricated by adding CTAB after pre-crystallization. High isomer selectivity (78.2%) was observed for the sea urchin-like SAPO-11 loaded with Ni.

A Mechanistic Study of the Multiple Roles of Oleic Acid in the Oil-Phase Synthesis of Pt Nanocrystals

Oleic acid (OAc) is commonly used as a surfactant and/or solvent for the oil-phase synthesis of metal nanocrystals but its explicit roles are yet to be resolved. Here, we report a systematic study of this problem by focusing on a synthesis that simply involves heating of Pt(acac)₂ in OAc for the generation of Pt nanocrystals. When heated at 80 °C, the ligand exchange between Pt(acac)₂ and OAc leads to the formation of a Pt^II -oleate complex that serves as the actual precursor to Pt atoms. Upon increasing the temperature to 120 °C, the decarbonylation of OAc produces CO, which can act as a reducing agent for the generation of Pt atoms and thus formation of nuclei. Afterwards, several catalytic reactions can take place on the surface of the Pt nuclei to produce more CO, which also serves as a capping agent for the formation of Pt nanocrystals enclosed by {100} facets. The emergence of Pt nanocrystals further promotes the autocatalytic surface reduction of Pt^II precursor to enable the continuation of growth. This work not only elucidates the critical roles of OAc at different stages in a synthesis of Pt nanocrystals, but also represents a pivotal step forward toward the rational synthesis of metal nanocrystals.

Selective, bifunctional Cu–WOx/Al2O3 catalyst for hydrodeoxygenation of fatty acids

Cu–WO_x/Al₂O₃ is highly selective for hydrodeoxygenation of oleic acid. Texture and acidity influenced the catalyst activity.

Hydrodecarboxylation of fatty acids into liquid hydrocarbons over a commercial Ru/C catalyst under mild conditions

100% stearic acid conversion can be achieved at even 160 °C alongside a 90.1% yield of heptadecane.

Effect of Pt Promotion on the Ni-Catalyzed Deoxygenation of Tristearin to Fuel-Like Hydrocarbons

Pt represents an effective promoter of supported Ni catalysts in the transformation of tristearin to green diesel via decarbonylation/decarboxylation (deCOx), conversion increasing from 2% over 20% Ni/Al2O3 to 100% over 20% Ni-0.5% Pt/Al2O3 at 260 °C. Catalyst characterization reveals that the superior activity of Ni-Pt relative to Ni-only catalysts is not a result of Ni particle size effects or surface area differences, but rather stems from several other phenomena, including the improved reducibility of NiO when Pt is present. Indeed, the addition of a small amount of Pt to the supported Ni catalyst dramatically increases the amount of reduced surface metal sites, which are believed to be the active sites for deCOx reactions. Further, Pt addition curbs the adsorption of CO on the catalyst surface, which decreases catalyst poisoning by any CO evolved via decarbonylation, making additional active sites available for deoxygenation reactions and/or preventing catalyst coking. Specifically, Pt addition weakens the Ni-CO bond, lowering the binding strength of CO on surface Ni sites. Finally, analysis of the spent catalysts recovered from deCOx experiments confirms that the beneficial effect of Pt on catalyst performance can be partially explained by decreased coking and fouling.

Deoxygenation of Stearic Acid over Cobalt-Based NaX Zeolite Catalysts

For the production of sustainable biofuels from lipid biomass it is essential to develop non-noble metal catalysts with high conversion and selectivity under inert gas atmospheres. Herein, we report a novel cobalt-based catalyst supported on zeolite NaX via ion-exchange synthesis. The resultant bifunctional cobalt-based NaX zeolite catalyst displayed high conversion of stearic acid to liquid fuels. In addition, the effect of reaction temperature and catalyst loading was studied to evaluate the order of reaction and activation energy. Decarboxylation and decarbonylation were the dominant deoxygenation pathways. Stearic acid was successfully deoxygenated in N2 atmospheres using Co/NaX catalysts with a conversion as high as 83.7% and a yield to heptadecane up to ~28%. Furthermore, we demonstrate that higher reaction temperatures resulted in competing pathways of decarboxylation and decarbonylation. Finally, the fresh and recycled catalysts were characterized showing modest recyclability with a ~12.5% loss in catalytic activity.

Continuous Hydrothermal Decarboxylation of Fatty Acids and Their Derivatives into Liquid Hydrocarbons Using Mo/Al2O3 Catalyst

In this study, we report a single-step continuous production of straight-chain liquid hydrocarbons from oleic acid and other fatty acid derivatives of interest including castor oil, frying oil, and palm oil using Mo, MgO, and Ni on Al₂O₃ as catalysts in subcritical water. Straight-chain hydrocarbons were obtained via decarboxylation and hydrogenation reactions with no added hydrogen. Mo/Al₂O₃ catalyst was found to exhibit a higher degree of decarboxylation (92%) and liquid yield (71%) compared to the other two examined catalysts (MgO/Al₂O₃, Ni/Al₂O₃) at the maximized conditions of 375 °C, 4 h of space time, and a volume ratio of 5:1 of water to oleic acid. The obtained liquid product has a similar density (0.85 kg/m³ at 15.6 °C) and high heating value (44.7 MJ/kg) as commercial fuels including kerosene (0.78-0.82 kg/m³ and 46.2 MJ/kg), jet fuel (0.78-0.84 kg/m³ and 43.5 MJ/kg), and diesel fuel (0.80-0.96 kg/m³ and 44.8 MJ/kg). The reaction conditions including temperature, volume ratio of water-to-feed, and space time were maximized for the Mo/Al₂O₃ catalyst. Characterization of the spent catalysts showed that a significant amount of amorphous carbon deposited on the catalyst could be removed by simple carbon burning in air with the catalyst recycled and reused.

Hydroisomerization of n-hexadecane over a Pd–Ni2P/SAPO-31 bifunctional catalyst: synergistic effects of bimetallic active sites

The Pd-Ni2P/SAPO-31 catalyst shows excellent performance in n-hexadecane hydroisomerization due to the synergistic effects of Pd–Ni2P and improved metal/acid balance.

Deoxygenation of Palmitic and Lauric Acids over Pt/ZIF-67 Membrane/Zeolite 5A Bead Catalysts

The deoxygenation of palmitic and lauric acids over 0.5 wt % Pt/ZIF-67 membrane/zeolite 5A bead catalysts is demonstrated. Almost complete conversion (% deoxygenation of ≥95%) of these two fatty acids was observed over both fresh and recycled catalyst after a 2 h reaction time. The catalysts displayed high selectivity to pentadecane and undecane via decarboxylation reaction pathway even at low 0.5 wt % Pt loading. Selectivity to pentadecane and undecane as high as ∼92% and ∼94% was observed under CO₂ atmosphere when palmitic and lauric acids were used respectively as reactants. Depending on the reaction gas atmosphere, two distinctive reaction pathways were observed: decarboxylation and hydrodeoxygenation. Specifically, it was found that decarboxylation reaction pathway was more favorable in the presence of helium and CO₂, while hydrodeoxygenation pathway strongly competed against the decarboxylation pathway when hydrogen was employed during the deoxygenation reactions. Esters were identified as the key reaction intermediates leading to decarboxylation and hydrodeoxygenation pathways.

One-step hydroprocessing of fatty acids into renewable aromatic hydrocarbons over Ni/HZSM-5: insights into the major reaction pathways

We describe the production of renewable aromatic hydrocarbons by a new facile one-step hydroprocessing of fatty acids with an in-depth exploration of the major reaction pathways and catalytic mechanisms.

Noble metal-free catalytic decarboxylation of oleic acid to n-heptadecane on nickel-based metal–organic frameworks (MOFs)

Herein we demonstrate novel noble metal-free catalytic systems based on Ni MOFs that can effectively convert oleic acid into heptadecane.

Mesoporous Ni/Ce1−xNixO2−y heterostructure as an efficient catalyst for converting greenhouse gas to H2 and syngas

A heterostructure of highly dispersed Ni nanoparticles in pore channels of Ni–CeO₂ solid solution, having excellent thermo-stability, redox properties, and metal/support synergy, is identified as an efficient nanocatalyst for converting greenhouse gas into H₂ energy and syngas.

Nanoparticles-in-concavities as efficient nanocatalysts for carbon dioxide reforming of methane to hydrogen and syngas

The ceria concavity-loaded Ni nanoparticle catalysts can lead to more active sites and promote CO₂ dissociative activation and CO desorption, thus enhancing significantly the catalytic performances for methane dry reforming with CO₂.

Cu, Al and Ga based metal organic framework catalysts for the decarboxylation of oleic acid

Herein we demonstrate the catalytic decarboxylation and conversion of oleic acid to paraffins and hydrocarbons over bare and Pt supported Cu, Al and Ga based metal organic frameworks.