Tuning the catalytic acidity in Al2O3 nanofibers with mordenite nanocrystals for dehydration reactions

Alumina (Al2O3) is one of the most used supports in the chemical industry due to its exceptional thermal stability, surface area, and acidic properties. Mesoscopic structured alumina with adequate acidic properties is important in catalysis to enhance the selectivity and conversion of certain reactions and processes. This study introduces a synthetic method based on electrospinning to produce Al2O3 nanofibers (ANFs) with zeolite mordenite (MOR) nanocrystals (hereafter, hybrid ANFs) to tune the textural and surface acidity properties. The hybrid ANFs with electrospinning form a non-woven network with macropores. ANF-HMOR, i.e., ANFs containing protonated mordenite (HMOR), shows the highest total acidity of ca. 276 μmol g-1 as determined with infrared spectroscopy using pyridine as a molecular probe (IR-Py). IR-Py results reveal that Lewis acid sites are prominently present in the hybrid ANFs. Brønsted acid sites are also observed in the hybrid ANFs and are associated with the HMOR presence. The functionality of hybrid ANFs is evaluated during methanol dehydration to dimethyl ether (DME). The proof of concept reaction reveals that ANF-HMOR is the more active and selective catalyst with 87% conversion and nearly 100% selectivity to DME at 573 K. The results demonstrate that the textural properties and the acid site type and content can be modulated in hybrid ANF structures, synergistically improving the selectivity and conversion during the methanol dehydration reaction. From a broader perspective, our results promote the utilization of hybrid structural materials as a means to tune chemical reactions selectively.

Non-mercury catalytic acetylene hydrochlorination over a NH4F–urea-modified Pd/HY catalyst for vinyl chloride monomer production

The modification of NH₄F and urea significantly enhances the stability of a Pd/HY catalyst for acetylene hydrochlorination.

Sustainable conversion of cellulosic biomass to chemicals under visible-light irradiation

Plasmonic nanostructure: a high conversion (>60%) of crystalline cellulose to chemicals was achieved with enhanced electromagnetic fields, E/E₀ = 10³ to 10⁶ times.

Surface plasmon-enhanced zeolite catalysis under light irradiation and its correlation with molecular polarity of reactants

The catalytic performance of zeolites can be boosted by the electric near-field enhancement (ENFE) of plasmonic Au-NPs induced by the localised surface plasmon resonance (LSPR) under visible light irradiation.