Effect of the calcination temperature on the oxygen evolution reaction over Pr₆O₁₁ oxide

Abstract

The Pr₆O₁₁ oxide synthesized using the citrate sol-gel method was calcined at four temperatures 600, 700, 800 and 900 °C. The prepared powder was characterized by DTA-TGA, XRD, IR, SEM and cyclic voltammetry. The thermal analysis shows an endothermic peak at 765°C attributed the pure cubic phase. XRD diffraction pattern reveal that three phases Pr₂CO₅, Pr₄O₇ and Pr₆O₁₁ coexist at 600°C. At T ≥ 700°C, the secondary phases Pr₂CO₅, Pr₄O₇ disappear while the phase Pr₆O₁₁ becomes alone indicating the formation of the pure cubic phase. The microstructural analysis shows that powders are constituted from particles having different shape, size and are agglomerated. The electrocatalytic properties of samples were investigated using cyclic voltammetry. The better electroactivity performance was achieved for the lower calcined electrode.