Selective shape control of cerium oxide nanocrystals for photocatalytic and chemical sensing effect

In this study, we report the precise shape control of crystalline cerium oxide, whose morphology changes between nanorods and nanoparticles in a short time. The proposed synthetic route of cerium oxide nanorods was highly dependent on the reaction time, and 10 min was determined to be the optimum synthetic condition. The cerium oxide nanorods were further converted into nanoparticles by the spontaneous assembly of cerium oxide nanoparticles into nanorods. The transmission electron microscopy results showed that the synthesized nanorods grew with high crystallinity along the 〈110〉 direction. The cerium oxide nanorods have been proven to be very efficient electron mediators for use as excellent photocatalytic materials and highly sensitive chemical sensors. The chemical sensor fabricated on a carbon paper substrate showed the high sensitivity of 1.81 μA mM^-1 cm^-2 and the detection limit of 6.4 μM with the correlation coefficient of 0.950.