Characterizations of nanostructured nickel aluminates as catalysts for conversion of glycerol: Influence of the preparation methods

Abstract Three different preparation methods were applied to prepare nickel aluminates (i.e. nanocasting (NiAlN), coprecipitation (NiAlC) and wet impregnation (NiAlW) methods). All catalysts exhibited the NiAl 2 O 4 phase besides that of NiO and γ-Al 2 O 3. The NiAlN catalyst showed nanoparticles of the aforesaid oxides whereas NiAl x O y was the predominant phase found over NiAlW catalyst. The performances of the nickel aluminate-based catalysts were evaluated in glycerol dehydration to produce valuable chemical compounds through the dehydration of glycerol. The sintering effects were responsible for the decreased performance of NiAlC in glycerol dehydration. On the contrary, NiAlN is found to be deactivated due to the lesser stability of its supported nanoparticles, being the glycerol conversion of ca. 3.3% at the end of the reaction. Besides, the reaction efficiently proceeded on NiAlW, which had a high catalytic performance with 19.7% glycerol conversion to acetol and others products and no deactivation along of the time for 25 h of time on stream was observed. This was due to the stability of the NiAl x O y phase, which impeded phase transformation and was resistant to heavy coking.