Synthesis of Pd/α-Fe₂O₃ nanocomposites for catalytic CO oxidation

Iron oxide and metal doped iron oxide nanocomposites have found attractive and versatile applications in many research areas such as catalysts, sensors, and biomedicine. This work reports a surfactant-free hydrolysis approach for the synthesis of hematite (α-Fe₂O₃) and Pd doped α-Fe₂O₃ nanoparticles with low-temperature catalytic activity. By this method, iron oxide rod-like nanoparticles were achieved by hydrolysis of ferric chloride salt with dilute HCl at a temperature of 100 °C. The Pd/iron oxide nanocomposites were obtained by adding citric acid into a mixture of iron oxide nanoparticles and palladium precursor (Pd(CH₃CN)₂Cl₂) under a reflux heating at 90 °C for 2 h. This method is featured as no use of any surfactants and templates, and no requirement of high-temperature thermal decomposition that are usually required for shape/size control in polar or nonpolar solvents. More importantly, it was found that the Pd/α-Fe₂O₃ nanocomposites exhibited high low-temperature catalytic activity in carbon monoxide (CO) oxidation.