Preparation of silver–tungsten nanostructure materials for selective oxidation of toluene to benzaldehyde with hydrogen peroxide

Abstract

We have developed a facile one-pot synthetic strategy to prepare Ag/WO₃ nanostructure materials with different morphologies using a cationic surfactant, cetyltrimethylammonium bromide. These materials were employed as catalysts in the direct synthesis of toluene to benzaldehyde using H₂O₂. The morphology of the Ag/WO₃ materials can be varied by changing the synthesis parameters. The size and shape of the Ag/WO₃ nanostructure catalyst has direct influence on the toluene conversion and benzaldehyde selectivity. The effect of different reaction parameters like reaction temperature, H₂O₂ to toluene molar ratio, reaction time, and so forth have been studied in detail. The Ag/WO₃ catalyst with ∼7 nm silver nanoparticles on the WO₃ nanorod with a diameter ∼60 nm showed the best catalytic activity of 42% toluene conversion with 93% benzaldehyde selectivity. The catalyst did not show any leaching up to four reuses, showing the true heterogeneity of the catalyst.