Marcela Frias Ordonez

Strontium titanate (STO) and its variants have emerged as leading materials in photocatalysis, particularly for degrading nitrogen oxides (NOx), due to their non-toxic nature, structural adaptability, and exceptional thermal stability. Although the one-pot sol-gel method leads to high-quality photocatalysts, areas remain for improvement. This study examines the impact of ethanol as a cosolvent in STO synthesis, focusing on optimizing the water-to-ethanol volume ratio. The findings reveal that a 1:3 ratio significantly enhances macropore formation and photocatalytic efficiency, achieving 42% NOx degradation under LED within three hours. Furthermore, incorporating 8.0 wt.% Ag into STO substantially improves visible light absorption and enables complete NOx elimination, thanks to enhanced charge separation and localized surface plasmon resonance. Even at high temperatures (1100 °C), the Ag-STO photocatalyst maintains partial activity, despite exceeding silver’s melting point. These results highlight the potential of STO-based materials for industrial applications, positioning them as a promising solution for effective NOx mitigation.

Slow kinetics is one of the capital issues of photocatalytic technology because of its heterogeneous nature, which involves multi-step processes. Herein, we show that the simple modification of the sol-gel-based TiO₂-smectite composite by hexadecyltrimethylammonium bromide (HDTMA) significantly boosts adsorption and photocatalytic efficient sol-gel-based light towards the removal of diclofenac from water. Three photocatalysts were prepared, including TiO₂, TiO₂-smectite, and HDTMA-TiO₂-smectite. The materials were characterized to understand the surface interaction and crystal characteristics. In terms of photoactivity, it was found that the addition of HDTMA to TiO₂-smectite improved the removal rate by twice. HDTMA changes the functional groups to TiO₂-smectite composite allowing enhanced adsorption and photoactivity through the so-called Adsorb and Shuttle process. The recycling tests show that HDTMA-TiO₂-smectite can be used up to four times with good performance. This modification approach could intensify the removal of pollutants from water instead of using complicated and costly techniques.