Sodium silicate solution

The compositions of the high-purity Metakaolin (ASTM C-618 [29 ] Class N pozzolans) (MetaMax^® BASF, NewYork, NY, USA) and Sodium silicate solution (Prochin Italia S.r.l., Caserta, Italy) used to prepare the alkali-activated reacting paste are reported in Table 1. Reagent-grade Sodium hydroxide anhydrous pellets (Sigma-Aldrich, St. Louis, MO, USA) were used to prepare the alkaline activating solution according to the procedures described in a previous paper [30 (link)].
The alkaline activating solution, prepared by dissolving Sodium hydroxide in the Sodium silicate solution in a 1/7.7 weight ratio, was equilibrated at room temperature for 24 h before adding the solid Metakaolin [30 (link),31 (link)]. Metakaolin solid powder was incorporated into the liquid alkaline activating solution maintained at 5 °C in a thermostated bath in a liquid-to-solid ratio of 1/1.7, mechanically mixed, and sonicated for 10 min.
The final composition of the whole geopolymeric system was previously determined by EDS analysis in a previous paper [30 (link)] as Al₂O₃ 3.48 SiO₂ 1.0 Na₂O 12.14 H₂O with a molar ratio Silica/Alumina of 3.48.

Vertical mesoporous silica films were synthesized in a CTAB–SDS–P123–water (0.75 g–0.99 g–25.70 g–125 g) system under pH 4.5 using an SDS/CTAB molar ratio of 1.67, a reaction temperature of 45 °C, and an aging time of 3 minutes. Then, a 2.75 g sodium silicate solution (≥27% SiO₂ basis, Sigma-Aldrich) with 150 g acidified aqueous solution (containing 5 g 1.2 M H₂SO_4(aq)), use NaOH_(aq) to adjust the pH to 4.5. After the condensation time of 3 minutes, the above CTAB–SDS–P123–water system was added and produced a white precipitate. The mixture was further placed in stainless steel pressure autoclaves with Teflon containers and aged for 24 h at 100 °C. Finally, the surfactant was removed by calcination at 600 °C for 6 h.

Sodium silicate solution (Na₂O(SiO₂)_x·xH₂O, reagent grade), sodium aluminate (NaAlO₂), sodium hydroxide (NaOH, ≥98%), 1-propanol (CH_₃CH_₂CH_₂OH, ACS reagent, ≥99.5%), tetradecyltrimethylammonium bromide (TTAB) (CH₃(CH₂)₁₃N(Br)(CH₃)₃, for synthesis) and amoxicillin (C₁₆H₁₉N₃O₅S, 95.0–102.0% anhydrous basis), used for the photocatalytic reactions, and terephthalic acid (98%) were purchased from Sigma-Aldrich (Burlington, MA, USA). Titanium (IV) n-butoxide (Ti(OCH₂CH₂CH₂CH₃)₄, reagent grade, 97%) was from ACROS Organics (Geel, Belgium). Nickel (II) nitrate ((Ni(NO₃)₂·6H₂O) and cobalt (II) nitrate ((Co(NO₃)₂·6H₂O) were from Merck (Darmstadt, Germany). Potassium iodide (KI) ethanol (C₂H₅OH) and p-benzoquinone (C₆H₄O₂), used as scavengers, were purchased from Merck.

The Au@SiO₂ nanoparticles (NPs) were prepared following the method described below^{31 (link)}. Briefly, Au NPs with an average size of 55 nm were prepared by adding 1.4 mL sodium citrate aqueous solution (1 wt%, 99%, Alfa Aesar) into 200 mL boiling HAuCl₄ aqueous solution (0.01 wt%, 99.99%, Sigma-Aldrich) under vigorous stirring. After that, the mixture was refluxed for 1 h and then cooled to room temperature. Following that, 0.6 mL 1 mM (3-Aminopropyl)triethoxysilane (APTES, 98%, Sigma-Aldrich) solution (pH 11) was added into 30 mL of Au NPs suspension solution and stirred for 15 min at room temperature. Then 3.2 mL sodium silicate solution (0.54 wt%, Sigma-Aldrich) was added to the above mixture and stirred for 5 min. After that, the mixture was kept in a 95 °C oil bath and stirred for another 30 min. The hot solution was then cooled in an ice bath followed by centrifugation at 3400×g and washed with DI water. Finally, the concentrated Au@SiO₂ NPs were dispersed in 500 μL H₂O.

To obtain the aluminosilicate gel, we used sodium silicate solution (26.5 wt.% SiO₂, 10.6 wt. % Na₂O, Sigma Aldrich, Darmstadt, Germany) and sodium aluminate (NaAlO₂, Sigma Aldrich) as silica and alumina sources, respectively. To provide the strong basic medium necessary for assembling structural units of zeolite Y, NaOH (98 wt.%, Lach-Ne) was chosen. Titanium (IV) n-butoxide (99%, Acros Organics, Geel, Belgium) and gold chloride (HAuCl₄aq, purum 51.5% Au brown, Fluka, Buchs, Switzerland) were used as precursors for the modification of zeolite Y with TiO₂ and Au species, respectively.

SBA-15
support was synthesized
using the following reagents: poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)
(Pluronic P123, Sigma–Aldrich); sulfuric acid (95%, Technical
VWR Prolabo Chemicals); sodium hydroxide (Technical VWR Prolabo Chemicals)
and sodium silicate solution (25%–28%, Sigma–Aldrich).
Iron(III) nitrate nonahydrate (Fe(NO₃)₃·9H₂O, Sigma–Aldrich); Cobalt(II) nitrate hexahydrate (Co(NO₃)₂·6H₂O, Sigma–Aldrich);
Nickel(II) nitrate hexahydrate (Ni(NO₃)₂·6H₂O, Alfa Aesar) and niobium(V) oxalate hydrate (C₁₀H₅NbO₂₀·H₂O, Alfa Aesar) were
used as precursor salts for bimetallic catalysts synthesis. Oxalic
acid dihydrate (C₂H₂O₄·2H₂O, Scharlau Chemie) was used to dissolve niobium(V) oxalate
hydrate.