Resorcinol–Formaldehyde/TiO <sub>2</sub> Polymer Composites: Efficient Photocatalysts for Oxidation of Water to Hydrogen Peroxide
Admassu Abebe, Ravinder Kaushik, Sunil Kumar, Iswar Chandra Mondal, Subrata Ghosh, Aditi Halder
Abstract
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 (H 2 O 2 ) are highly desirable. In this context, the photocatalytic generation of hydrogen peroxide (H 2 O 2 ) 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 TiO 2 (RF/TiO 2 ) composites as an efficient heterogeneous platform for photocatalytic production of H 2 O 2 through water oxidation. The synthesis of RF/TiO 2 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 TiO 2 in RF/TiO 2 composites in improving the photocatalytic activity of resorcinol–formaldehyde resin was established by developing RF/TiO 2 composites with varied amounts of TiO 2 . As experimentally established, the RF/TiO 2 composites prepared with 1.1–1.6% (w/w) feed of TiO 2 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/TiO 2 -1.2% and RF/TiO 2 -1.3% resulted in the production of ∼500 and ∼530 μmol of H 2 O 2 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 H 2 O 2 production rate can be enhanced by increasing the reaction temperature.