Development and characterization of electro active CeO2-RuO2 mixed oxide and its role in alkaline hydrogen evolution reaction

Ni-P coating incorporated with CeO2-RuO2 mixed oxide with optimum phosphorus content had remarkable catalytic activity during hydrogen evolution reaction (HER). Characteristics of the mixed oxide catalysts play crucial role in the catalytic activity. Here we tuned the crystalline characteristics of the CeO2-RuO2 mixed oxide by varying calcination temperature. The mixed oxide had rutile RuO2 and fluorite CeO2 of {111} dominant phase. The optimized mixed oxide was characterized thoroughly by Xray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) analysis. The redox property of cerium ions via oxygen vacancy formation by ruthenium incorporation and the crystalline characteristics were responsible for the catalytic activity. The CeO2-RuO2 mixed oxide was incorporated into Ni-P coating on mild steel. The composition of CeO2-RuO2 mixed oxide in the coating was tuned and was explored as electrode for HER. Optimized surface properties and composition of the electrode facilitated the HER. The catalytic Ni-P electrode incorporated with an optimum content of CeO2-RuO2 (5 g L-1) exhibited very low overpotential as low as 180 mV at 250 mA cm(-2) during hydrogen evolution reaction in 32% (w/v) NaOH. The electrochemical HER mechanism involves Volmer chemical adsorption of H-2 on metal oxide and the chemical desorption of H-2 gas by Heyrovsky. (C) 2018 Elsevier B.V. All rights reserved.