Catalysis plays a pivotal role in green chemistry practices, particularly in reducing waste generated during chemical synthesis. Decatungstate (DT) emerges as a potent photocatalyst for Type I oxidations, exhibiting remarkable resilience to oxygen quenching, a characteristic that sets it apart from other excited triplet state photocatalysts. While homogeneous DT catalysis demonstrates effectiveness, its solubility poses challenges for its separation and recycling. To address these limitations, we focus on the development and comparison of heterogeneous DT photocatalysts, aiming to optimize their yield, recovery, and reusability. We synthesized tetrabutylammonium decatungstate (TBADT)-supported catalysts using silica, alumina, titanium dioxide, and glass wool and characterized them using diffuse reflectance measurements. Subsequently, we evaluated their photocatalytic performance by monitoring the oxidation of 1-phenylethanol and cyclohexanol under UVA irradiation. Our findings reveal that TBADT@silica emerges as the most effective catalyst, achieving approximately 20% conversion of cyclohexanol and 50% conversion of 1-phenylethanol with good reusability. Interestingly, we observed that 3-aminopropyl-triethoxysilane (APTES) treatment, intended to enhance DT anchoring, unexpectedly quenches the ³DT* triplet state, reducing catalytic activity. This unexpected finding underscores the importance of careful consideration in designing robust and recyclable heterogeneous decatungstate catalysts. Our research contributes significantly to the advancement of heterogeneous photocatalysis, paving the way for future applications in flow photochemistry. Further, we share a Python code (Google 3.12.11) to correct spectra obtained in Cary spectrometers.

The United Nations and the World Health Organization provide clear guidelines to ensure water security for urban and rural populations. Common contaminants include bacteria and a variety of organic contaminants, such as medications and agricultural runoff. The rapid advancement of point-of-use water treatment is crucial to align with these international recommendations. While some problems are chronic and require long-term solutions, others are transient contamination issues that occur without warning and frequently lead to boil water advisories that can last for extended periods. In these cases, providing reliable water security requires solutions that can be deployed rapidly, are affordable, and can be implemented at the point of use with minimal operator training. Our research explores the state of the art in photocatalysis as a method for purifying water from organic contaminants and bacteria. We present a comparative analysis of various catalysts, supports, and light sources, along with our perspective on the benefits of flow systems. Practical solutions require flow techniques that are portable and can address at least the recommended survival requirements of ~7.5 L per capita per day for small communities, schools, or small hospitals. In this perspective, we propose that flow-compatible modified TiO₂ catalysts can offer practical solutions implemented with either solar light or LED sources in the UVA or visible region.