## 3 Results and Discussion
### Photocatalytic Tests  
Simulated solar light photo-oxidation processes of organic matter are important for several practical reasons: (i) they require low material and operational costs, (ii) they have the potential to clean water and air by mineralizing organic pollutants to CO\({}_{2}\)[35, 37, 75, 76], and (iii) they are attractive alternative routes for the selective synthesis of high-added-value oxygenated products [38, 77]. Ethanol is a common compound obtained from biomass, with its photodegradation being important for hydrogen production and depollution. But it can also be present as a contaminant in air and industrial wastewater [37, 78]. The procedure can be depicted from Figure 16. The representative samples, namely LTA and LTA-Pt, were selected for photocatalytic tests. The photoactive surface was exposed to simulated solar light (AM1.5). The photocatalytic test lasted three hours. Photocatalytic tests are conducted at a 20% oxygen concentration. The main intermediate in the ethanol photogeneration process is acetaldehyde, which can be further oxidized in CO\({}_{2}\) and H\({}_{2}\)O. Table 8 shows the experimental data for reactant and product distribution, and ethanol conversion over bare and platinum-modified powder in the gaseous phase after 3 h of reaction time. The conversion of ethanol is 14.29% (for LTA) and 29.75% (for LTA-Pt), meaning that platinum modification influences catalytic activity. At the end of the reaction time, both catalysts show the formation of mild oxidation products of ethanol (acetaldehyde and formic acid), as well as carbon dioxide, with the highest value obtained for LTA-Pt. Figure 16: The experimental setup used for the photodegradation of ethanol in the gaseous phase under simulated solar light. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**C\({}_{\text{IN}}\) (umoles)**} & \multicolumn{4}{c}{**C\({}_{\text{OUT}}\) (umoles)**} & \multicolumn{1}{c}{} \\ \cline{2-7}
**Catalyst** & **Ethanol** & **Ethanol** & **Acetaldehyde** & **Formic Acid** & **Carbon** & **Ch\({}_{3}\)CH\({}_{2}\)OH (\%)** \\  & **(CH\({}_{3}\)CH\({}_{2}\)OH)** & **(CH\({}_{3}\)CH\({}_{2}\)OH)** & **(CH\({}_{3}\)CHO)** & **(HCOOH)** & **Dioxide** & **(CO\({}_{2}\))** & \\ \hline LTA & 243.15 & 208.39 & 11.18 & 0.29 & 5.13 & 14.29 \\ LTA-Pt & 243.45 & 171.02 & 36.47 & 1.06 & 13.67 & 29.75 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Ethanol degradation in gaseous phase measured after 3 h of reaction. Figure 17 shows the comparative results for the oxidative degradation of ethanol on LTA and LTA-Pt catalysts exposed to simulated solar light. CH\({}_{3}\)CHO and HCOOH are formed successively in the complex process of the mineralization of CH\({}_{3}\)CH\({}_{2}\)OH to CO\({}_{2}\). The blank test has been used to correct the results. Figure 17: The results obtained for the gaseous phase oxidative degradation of ethanol using La\({}_{2}\)Ti\({}_{2}\)O\({}_{7}\) catalysts exposed to simulated solar light: (**a**) amount of CH\({}_{3}\)CH\({}_{2}\)OH photo-degradated in time, (**b**) conversion of CH\({}_{3}\)CH\({}_{2}\)OH, (**c**) amount of CH\({}_{3}\)CHO produced in time, (**d**) selectivity to CH\({}_{3}\)CHO, (**e**) amount of HCOOH produced in time, (**f**) selectivity to HCOOH, (**g**) amount of CO\({}_{2}\) produced in time and (**h**) selectivity to CO\({}_{2}\). The photodegradation of ethanol is presented in Figure 17, showing reaction sequences to create intermediates. Figure 17g,h show the photo-oxidative degradation of ethanol to CO\({}_{2}\) (and water) under simulated solar light irradiation. The materials investigated show activity in terms of ethanol mineralization in the gaseous phase. The higher production is recorded for LTA-Pt, which produces around 14 \(\upmu\)moles CO\({}_{2}\) after 3 h. Both catalysts of interest prove their activity in ethanol photodegradation.