Resorcinol–Formaldehyde/TiO2 Polymer Composites: Efficient Photocatalysts for Oxidation of Water to Hydrogen Peroxide

Given its multifaceted important roles such as aqueous oxidant, chemical platform for environmental remediation, possible liquid fuel, and so on, environmentally friendly approaches to produce hydrogen peroxide (H2O2) are highly desirable. In this context, the photocatalytic generation of hydrogen peroxide (H2O2) from water oxidation has emerged as a promising method, and phenol–formaldehyde-based functional resins have been established as an excellent platform for developing photocatalysts for water oxidation. The present work reports the development of resorcinol–formaldehyde (RF) and TiO2 (RF/TiO2) composites as an efficient heterogeneous platform for photocatalytic production of H2O2 through water oxidation. The synthesis of RF/TiO2 was accomplished following a simple high-temperature hydrothermal method, and it was characterized to study its microstructures and optical properties. The role of the optimum amount of TiO2 in RF/TiO2 composites in improving the photocatalytic activity of resorcinol–formaldehyde resin was established by developing RF/TiO2 composites with varied amounts of TiO2. As experimentally established, the RF/TiO2 composites prepared with 1.1–1.6% (w/w) feed of TiO2 with respect to resorcinol at a temperature of 200 °C under hydrothermal conditions were found to be the most efficient ones for the present study. Out of these composites, RF/TiO2-1.2% and RF/TiO2-1.3% resulted in the production of ∼500 and ∼530 μmol of H2O2 per gram of catalyst, respectively, upon 5 h of continuous photoirradiation under the present experimental conditions with a reaction temperature of ∼30–35 °C. It was observed that the H2O2 production rate can be enhanced by increasing the reaction temperature.