2.3. Material characterization
The basicity and hydrophilic character of the as-prepared samples were assessed through TPD of CO2 and water (A Azzouz et al., 2006; Beltrao-Nunes et al., 2019; Terrab et al., 2016). This was obtained by putting 45-50 mg of each sample at heating rate of 5 °C.min-1 from 20 °C to 450 °C and under a nitrogen stream of 5 mL.min-1 after saturation of each sample with CO2 gas (Scheme. S3 ). Deeper insights into the structure of the as-synthesized MNPS/H20@NaMt and MNPS/H20@CT materials were achieved through TG Analysis (TA Instruments TGA (Q500)/Discovery MS equipment). For this purpose, 4-7 mg samples were heated in platinum (Pt) pan at a temperature range of 20-500 °C and 10 °C/min heating rate under 30 mL/min dry argon stream (Fig. S1 ). The particle morphology of the material was screened by SEM (Jeol JCM-6000 PLUS instrument). The samples were spread as powder on conductive double adhesive carbon tapes (Fig. S2 ). The SEM analysis of non-conductive samples was performed at 1.0 kV voltage, versus 15 kV for metal-containing materials (conductive). The crystalline structure was investigated by XRD in 2-Theta range 10-80, using CuKalpha radiation (1.5406 Å) and XRD D8 Advance device (Fig. S3 ). Metal-matrices interactions were assessed through XPS of 7800 × 300 µm spots by means of an AXIS-ULTRA instrument (by KRATOS Analytical Ltd, UK) and a monochromatic Al-based X-ray source (260 watts in constant pass energy mode in two 160eV and 1eV steps).