Investigating the state of Fe and La in MCM-41 mesoporous molecular sieve materials

Modification of structured bio‑carbon derived from spongin-based scaffolds with nickel compounds to produce a functional catalyst for reduction and oxidation reactions: Potential for use in environmental protection

Three different 3D fibrous-like NiO/Ni(OH)₂/Ni‑carbonized spongin-based materials were prepared via a simple sorption-reduction method. Depending on the support used, the catalysts were composed of carbon, nickel oxide, nickel hydroxide and zero-valent nickel, with the surface content of the nickel-containing phase in the range 15.2-26.0 wt%. Catalytic studies showed promising activity in the oxidation of phenolic compounds in water and in the reduction of 4-nitrophenol. The oxidation efficiency depends on the substrate used and ranges from 80% for phenol at pH 2 to 99% for 4-chlorophenoxyacetic acid (4-CPA) and methylchlorophenoxypropionic acid (MCPP). In the reduction reaction, all catalysts exhibited superior activity, with rate constants in the range 0.648-1.022 min^-1. The work also includes a detailed investigation of reusability and kinetic studies.

Methyl oleate deoxygenation for production of diesel fuel aliphatic hydrocarbons over Pd/SBA-15 catalysts

Background

Catalytic deoxygenation is a prominent process for production of renewable fuels from vegetable oil. In this work, deoxygenation of technical grade methyl oleate to diesel fuel aliphatic hydrocarbons (C₁₅ – C₁₈) is evaluated with several parameters including temperature, hydrogen pressure and reaction time in a stirred batch reactor over Pd/SBA-15 catalysts.

Results

Two different SBA-15 morphologies i.e. spherelike and necklacelike structures have been synthesize as supports for Pd active metal. It is found that Pd dispersion on necklacelike SBA-15 is higher than that of spherelike SBA-15. Notably, higher Pd dispersion on necklacelike SBA-15 provides significant deoxygenation efficiency as compared to Pd/SBA-15-spherelike. Results show that H₂ pressures greatly determine the total ester conversion and selectivity to C₁₅ – C₁₈ aliphatic hydrocarbons. Total ester conversions with 55< selectivity to n-heptadecane are achieved using Pd/SBA-15-necklacelike at 270°C and 60 bar H₂ pressure within 6 h reaction time. Gas phase study reveals that formation of C₁₇ is generated via indirect decarbonylation when the reaction time is prolonged.

Conclusions

Pd/SBA-15-necklacelike catalyst exhibits good catalytic performance with high selectivity to diesellike aliphatic hydrocarbons (C₁₅ – C₁₈). The physicochemical properties of the Pd supported on different SBA-15 morphologies influence the deoxygenation activity of the catalysts. Furthermore, the reaction pathways are governed by the H₂ pressure as well as reaction duration.

Synthesis, characterization of an AlPO-CJ2 analogue containing heteroatomic Eu

An analogue of AlPO-CJ2 microporous aluminophosphate containing heteroatomic Eu was hydrothermally synthesized in situ in the reactant system of carbamide-NH4-F-Al2O3-P2O5-H2O, and characterization by ICP, powder XRD, Mössbauer spectra, 31P MAS NMR and luminescent spectroscopy prove that Eu is incorporated into the framework.