Aluminum isopropoxide

Tetraethoxysilane (TEOS) (98%, Aldrich) was used as a silica source. Aluminum isopropoxide (98%, Aldrich), tetraethylammonium hydroxide (TEAOH) (20 wt% in water, Aldrich), and double-distilled water were used as the other reactants. The molar composition of the gel used for the synthesis of nanozeolite beta was 0.25Al₂O₃:25SiO₂:490H₂O:9TEAOH. Aging with clear solution was continued under static conditions for 4 h. The crystallization was completed within 17 days under static conditions at 100°C in Teflon-lined autoclaves. The product was separated by centrifugation, washed with distilled water, and dried at 40°C [11 (link)]. An approximate particle size of nanozeolite beta was 60 nm.

The reagents used for the synthesis of PST-5 included diethylamine (DEA, 99.5+%, Aldrich), aluminum isopropxide (98+%, Aldrich), phosphoric acid (85%, Merck), and deionized water. PST-5 was synthesized from an AlPO₄ gel with the composition of 2.0DEA·1.0Al₂O₃·1.0P₂O₅·40H₂O, where DEA is diethylamine. In a typical synthesis of PST-5, 3.84 g of o-H₃PO₄ (85%, Merck) was diluted in 5.63 g of H₂O. This solution was added dropwise to a slurry of 6.95 g of aluminum isopropoxide (>98%, Aldrich) in 5.64 g of H₂O. After stirring for 1 h, 2.45 g of DEA (99.5%, Aldrich) was added to the above synthesis mixture, which was stirred overnight at room temperature. Afterwards, the mixture was charged into a Teflon-lined 23-mL autoclave and heated under static conditions at 200 °C for 5 days. The resulting white powder was recovered by filtration, washed repeatedly with water and then dried overnight at room temperature.

A general synthesis procedure was as follows. First, tetraethylorthosilicate (Aldrich) was added to the OSDA in its hydroxide form. For aluminosilicates, aluminum isopropoxide (Aldrich) was then added and for titanosilicates titanium(iv) butoxide (Aldrich) was added. The container was closed, and stirred for at least 12 h to allow for complete hydrolysis. The lid was then removed, and the alcohol and appropriate amount of water were allowed to evaporate under a stream of air. Composition was monitored gravimetrically. Additional water was added as necessary, and then aqueous HF (48 wt%, Aldrich) was added and the mixture was stirred by hand until a homogenous gel was obtained. (Caution: use appropriate personal protective equipment, ventilation and other safety measures when working with HF.) If necessary, a second evaporation step was used after the addition of HF to reach the necessary water level. The final molar ratios are given in Table S1.† The autoclave was sealed and placed in a rotating oven at 175 °C. Aliquots of the material were taken periodically by first quenching the reactor in water and then removing enough material for X-ray powder diffraction (XPD).

The chemicals in this study were used as purchased: titanium (IV) isopropoxide (TTIP, 97%), nitric acid (HNO₃, 65%), aluminum isopropoxide (>98%, Aldrich). All reagents were purchased from Sigma-Aldrich. 96% ethanol was purchased from ChimMed, Russia. All aqueous solutions were prepared by using highly pure water from Millipore Elix (15 MOm/cm³). Soda-lime glass plates were used as substrates (microscope slides 26 mm × 76 mm, Paul Marienfeld, Germany). Polymeric substrate are pre-cut A4 PET film sheet (ChimMed, Russia). Indium tin oxide coated glass slide, rectangular 15–25 Ω/sq, slide (Aldrich). Substrates were sonicated in USI bath, rinsed with isopropanol, and dried in a flow of air.

SiC (β-phase, 95%, 50 nm average size) nanoparticles were purchased from Alfa Aesar (Haverhill, MA, USA) or PlasmaChem (Berlin, Germany), depending on the availability of the material in each commercial brand. In the case of the up-scaling process, the SiC nanoparticles were purchased from Hwnano (Guangzhou, China) as they were able to supply a higher amount of nanoparticles. 500 nm SiC nanoparticles (β-phase, 95%, 500 nm average size) were also purchased from Hwnano (Guangzhou, China). In any case, the chosen SiC nanoparticles were those that presented a layer of silicon oxide, as these helped the formation of the oxide shell. The particles covered with a layer of carbon did not allow the formation of the shell. Titanium(IV) isopropoxide (Ti(OⁱPr)₄, 97%), aluminum isopropoxide (Al(OⁱPr)₃, 98%), aluminum sec-butoxide (Al(O^sBu)₃, 97%), yttrium isopropoxide (Y(OⁱPr)₃, solution 20–25 wt.% in toluene), iron(III) acetylacetonate ((Fe(acac)₃, 97%), and triethylene glycol (TREG) were purchased from Aldrich (St. Louis, MO, USA). Other solvents and acids (hydrochloric acid 37%, glacial acetic acid, 2-propanol, Analytical Grade) were purchased from Scharlab (Barcelona, Spain). All the reactants were used as obtained from the commercial brand without any further purification.