Nanosized Ir x Ru 1− x O 2 electrocatalysts for oxygen evolution reaction in proton exchange membrane water electrolyzer

Normally in proton exchange membrane water electrolysis (PEMWE), the anode has the largest overpotential at typical operating current densities. By development of the electrocatalytic material used for the oxygen evolving electrode, great improvements in efficiency can be performed. In electrochemistry, rare metallic oxides RuO 2 and IrO 2 exhibit the best catalytic properties for the oxygen evolution reaction (OER) in acid electrolytes compared to other noble metals. RuO 2 is the most active catalyst and IrO 2 is the most stable catalyst. An oxide containing both elements is therefore expected to be a good catalyst for the OER. In this study Ir x Ru 1− x O 2 nanosized powder electrocatalysts for oxygen evolution reaction is synthesized by hydrolysis method. Cyclic voltammetry, anodic polarization and galvanostatic measurements were conducted in solution of 0.5 M H 2 SO 4 to investigate electrocatalytic behavior and stability of the electrocatalyst. The mechanisms of the thermal decomposition process of RuCl 3 .nH 2 O and IrCl 3 .mH 2 O precursors to form oxide powders were studied by means of thermal gravity analysis (TGA). X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used analysis for determination of the crystallographic structure, morphology and catalysts particle size. Based on the given results, the Ir x Ru 1− x O 2 ( x = 0.5; 0.7) compounds were found to be more active than pure IrO 2 and more stable than pure RuO 2 .