# TiO2 Modified Geopolymers for the Photocatalytic Dye Decomposition
## 2 Materials and Methods
### Methods  
The dried solid-geopolymer samples were pulverized by a Retsch friction mill (the particle size of 0-0.2 mm). Afterward, the samples were stored in a sealable plastic bag to prevent an increase in the moisture content. The materials prepared in this way were used in the subsequent analyses.  
A non-destructive X-ray fluorescence (XRF) spectrometer (Spectro IQ, Kleve, Germany), equipped with an HOPG Barkla crystal was used to determine chemical compositions. The tested samples were prepared by the pressed-pellet method (4.0 g of the material and 0.9 g of the binding additive HWC Hoechst wax, Germany). For the evaluation, X-LabPro software was utilized.  
For the determination of the loss on ignition (LOI), the samples were pre-dried and pulverized (at 105 \({}^{\circ}\)C up to a constant weight, the particle size of 0-0.2 mm) and subsequently heated in a muffle furnace (a temperature rise of 10 \({}^{\circ}\)C/min) to a temperature of 1000 \({}^{\circ}\)C with a dwell of 10 min.  
Microscopic studies of the samples were performed using an SEM (scanning electron microscope) equipped with an Apollo EDS (energy dispersive spectrometer) silicon drift Si(Li) detector with a FET preamplifier for chemical element X-ray microanalysis. Data were acquired on EDAX TSL OIM software with ZAF corrections. Analyses were performed on polished blocks and powder obtained by milling or rubbing individual samples.  
Particle-size distribution was measured by a CILAS 920L (CILAS, Orleans, France) analyzer with a range of 0.7-400 \(\upmu\)m, using material suspension in water and detecting particle sizes via the laser-beam reflection. The mean hydrodynamic diameter of industrial TiO\({}_{2}\) powder, D\({}_{\mathrm{H}}\), was measured by a 90 Plus/BI-MAS analyzer (Brookhaven Instruments Corp., Holtsville, NY, USA) using dynamic light scattering (DLS). D\({}_{\mathrm{H}}\) values were measured for 30 s at 10 replications, and these data were statistically processed according to the ISO 13321 and 22412. Before measurement, the solids were mixed with water by a laboratory shaker for 25 min. For more details, see [49].  
The powder X-ray diffraction (XRD) patterns (Cu K\(\alpha\), \(\lambda\) = 1.5418 A) were recorded on powdered samples using a D8 Advance diffractometer (Bruker AXS, Karlsruhe, Germany) with a Bragg-Brentano \(\theta\)-\(\theta\) goniometer (radius 217.5 mm) equipped with a Ni-beta filter and a LynrxEye detector. The scan was performed at room temperature from 5 to 80\({}^{\circ}\) (2 0) in 0.01\({}^{\circ}\) steps with a counting time of 1 s per step. The mass concentrations of the phases present were calculated by full-pattern matching using EVA software [50; 51]. For each selected pattern, EVA adjusted the scaling factor and width parameters by fitting, and the results were transformed into concentrations using the I/I\({}_{\mathrm{cor}}\) factors from the PDF-4+ database [52].  
The Fourier transform infrared (FTIR) transmission spectra of the samples were measured by an FTIR Thermo Nicolet Nexus spectrophotometer using the KBr technique with a total number of 128 scans and the resolution of 4 cm\({}^{-1}\). A 3 mm aperture was used for these measurements. The spectra were normalized to the band with the highest intensity. The parent geopolymer material was used as the background for incorporated photocatalysts.