Structural characterization of NiO doped with several caesium loadings

Several samples obtained from doping NiO with different loading amounts of caesium oxide were structurally characterized using BET, TPR, XRD, XPS and SEM techniques. From BET results, increasing caesium contents decrease surface areas except at temperatures with partial reduction. TPR shows that high caesium loadings can promote NiO reduction at the beginning of its reduction contrarily to previously reported potassium behaviors, and also a reduction inhibiting counter-effect at the end of the reduction curves with the same increasing caesium loadings. XRD and SEM clearly show differentiated crystalline morphologies on the oxidized and reduced caesium-doped nickel phases obtained from the solids studied. XPS results show the reducibility behaviour of the solid surfaces confirming the NiO reduction promoting effect with increasing caesium loadings and also a dramatic caesium migration towards the surface of the solids mainly at initial reduction temperatures. That abundant surface caesium content delays the complete reduction of the solids.