The present work demonstrates an efficient continuous flow methodology for the preparation of iron oxide nanoparticles supported on porous silicates. The effect of the iron precursor solution feed rate, the synthesis temperature and time and the support type on the catalyst characteristics were studied, as well on the catalytic activity in the microwave-assisted oxidation of benzyl alcohol with hydrogen peroxide and in the alkylation of toluene with benzyl chloride and with benzyl alcohol. The method appeared to deposit more α-Fe2O3 (hematite) on the support surface compared to similar catalyst materials synthesized using other methods. The catalyst deactivation observed in consecutive reaction cycles was mostly due to the blocking of active sites rather than metal leaching from the catalyst framework. © 2018 The Royal Society of Chemistry.