Synthesis of 1D nanostructures of RNiO3 oxides and applications
Different fields of application of nickelates oxides (RNiO3, R = La, Pr, Nd...) and their nanostructures have been explored. Thus, in this work, we explore the synthesis of 1-D oxide nanostructures, such as LaNiO3 and NdNiO3 nanofibers and nanotubes, obtained by different techniques (template-assisted and electrospinning methods) and some applications, as flexible pressure sensors and electrochemical biosensors. The results showed the possibility to obtain nanofibers and nanotubes with a high surface/volume aspect ratio. LaNiO3 nanofibers with mean diameters of 370 μm, with lengths greater than 10 μm and a distorted rhombohedral crystal structure were obtained. NdNiO3 nanotubes with different diameters (ranging from 20 to 150 nm) were obtained. The nanotubes presented a distorted orthorhombic perovskite structure with a high degree of orientation and uniformity. Furthermore, nanotubes diameters showed to affect nickel valence in these systems, modifying physical properties. From the synthesis and characterization of these nanostructures, two devices were developed: the first one was the flexible pressure sensor based on the deposition of LaNiO3 nanofibers onto paper and sandwiched in PDMS, and the other was the electrochemical biosensor for ascorbic acid detection based on NdNiO3 nanotubes. Both devices showed promising in their applications and show the possibility to increasingly explore different fields of applications of nickel oxide nanostructures.