Decoration of an inorganic layer with nickel (hydr)oxide via green plasma electrolysis

Abstract

In this study, we describe the green plasma electrolysis of a magnesium alloy in alkaline electrolyte to produce a hybrid inorganic layer with nickel (hydr)oxide incorporated in a matrix of magnesium oxide, and investigate the electrochemical and optical properties of this material. The addition of Ni(NO₃)₂·6H₂O to the electrolyte reduced the size of the micro-defects found in the inorganic layer after plasma electrolysis by inducing soft plasma discharges. As a result, through cyclic voltammetry and polarization tests, the corrosion stability of the sample containing nickel (hydr)oxide was significantly enhanced. Measurement of the optical properties reveals that the material possesses excellent energy efficiency as indicated by a high solar absorptivity of ∼0.92 and a low infrared emissivity of ∼0.13 which are presumably due to the inherent dark-brown colour of nickel (hydr)oxide. We expect that these results will have implications in the development of functional materials with excellent optical and corrosion properties by considering green processing utilizing alkaline electrolyte.