Inkjet Printing as High-Throughput Technique for the Fabrication of NiCo2O4 Films

Owing to its distinctive physicochemical properties, nickel-cobalt mixed oxide (NiCo2O4) has become a promising and innovative material for applications in many technological fields. The design of fast and reliable techniques for the deposition of this material is essential in the development of applications. In this work, NiCo2O4 films were successfully prepared by an inkjet printing technique using a suitable ink obtained from metal nitrates in a glycerol-water mixture. In order to deposit well-defined and uniform film patterns, the instrumental parameters such as drop spacing and inkjet voltage have been explored. The pure crystalline bimetallic nickel cobaltite oxide is obtained at 500 degrees C with a homogeneous compositional distribution along the film. The average thickness observed by scanning electron microscopy is around 490 nm, whereas X-ray photoelectron spectroscopy analysis revealed that the film surface presents mixed oxidation states for both metals: Co2+, Co3+, Ni2+, and Ni3+. The electrocatalytic performance of inkjet-printed NiCo2O4 films for the water oxidation reaction is comparable with earlier reports.