Preparation of Nickel Aluminum–Manganese Spinel Oxides NixAl1−xMn2O4 for Oxygen Electrocatalysis in Alkaline Medium: Comparison of Properties Stemming from Different Preparation Methods
1999; Elsevier BV; Volume: 145; Issue: 1 Linguagem: Inglês
10.1006/jssc.1999.8162
ISSN1095-726X
AutoresJilberto Ponce, Edmundo I. Ríos, Jean-Luc Rehspringer, G. Poillerat, P. Chartier, Juan Luis Gautier,
Tópico(s)Microwave Dielectric Ceramics Synthesis
ResumoTwo different procedures were used to prepare spinel-type NixAl1−xMn2O4 (0≤x≤1) compounds to study the effects of solid state properties of mixed oxides on their electrocatalytic properties. The oxalic route, coprecipitation of metal oxalates dissolved in propanol or ethanol, and the propionic route, hydrolysis of metal carboxylates in propionic acid, have been used. In both routes, thermal decomposition produces the corresponding oxides. X-ray diffraction patterns showed that the oxides crystallize in a cubic spinel phase with a unit cell parameter a that increases as aluminum is replaced by nickel. At low x values, compounds prepared by the propionic route showed a larger variation for parameter a than compounds prepared by the oxalic route, probably due to oxygen stoichiometric deficiency. This effect was estimated from the tetrahedral force constant (kt) values, which showed a fast decrease as x varied from 0 to 1. Electrical conductivity, conduction activation energy, hole mobility, and pHz of oxides prepared by the propionic route were also higher than those from oxides prepared by the oxalic route. Crystallinity grade and particle size were nearly 50′ higher in propionic-route samples than in oxalic-route samples. The apparent and real electrocatalytic activities of both types of oxides were compared for O2 evolution.
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