Screen-printed nickel hydroxide electrodes: Semiconducting, electrocatalytic, and electrochromic properties

This work presents a methodology to develop functional metal-oxide based inks for screen-printing. Nickel hydroxide has been grown by co-precipitation on the surface of conducting microparticles using different par-ticle to nickel salt ratios. The resulting particles formed the basis of screen-printing inks, used to print elec-trodes and test structures. The work describes the characterization of the materials through the different stages of development using a range of techniques including SEM, TEM, electrochemical and spectroscopic techniques. The screen printed electrodes have demonstrated their ability to oxidise water at 0.7-0.8 V vs Ag, making them suitable for electrolyzers. Also, glucose can be directly oxidised at these electrodes below 0.6 V vs Ag, with a detection limit around 65 mu M, also pointing to enzyme-less biosensing applications. The electrodes also display electrochromism, with charge efficiencies in the range of 50 cm2 C-1. Last, the elec-trodes present an optical bandgap in the range 4.06-4.15 eV, determined by diffuse reflectance spectroscopy. The approach presented here is extensive to other metal oxides, which opens the range of possible screen -printed semiconductors and catalysts considerably.