Synthesis and characterization of monolithic ZnAl 2O 4 spinel with well-defined hierarchical pore structures via a sol-gel route

摘要

AbstractHierarchically porous ZnAl2O4spinel monolith derived from ionic precursors has been successfully prepared via the sol-gel route accompanied by phase separation in the presence of poly (ethylene oxide) (PEO) and propylene oxide (PO). Appropriate amounts of PEO as a phase-separation inducer and PO as a gelation mediator allow the formation of the xerogel with bicontinuous macrostructure and a monolithic shape. The macropore size of the resultant dried gel is mainly distributed in the range of 0.2–1?μm, and the whole porosity is about 65%. The dried gel is constructed by crystalline ZnAl hydrotalcite, becoming amorphous after heat-treated at 300–500?°C in air, and is further transformed into single phase ZnAl2O4spinel with plate-like shape at 600?°C. The macroporous structure is well maintained while the porosity increases to 75% and the surface area rises to 109?m2?g?1after heat-treatment.Graphical abstractDisplay OmittedHighlights?ZnAl2O4were constructed into certain bicontinuous macrostructure with a monolithic shape.?Possessing three dimensional mesostructured skeletons and interconnected macropore channels.?First report on the synthesis and characterization of such macro-mesoporous ZnAl2O4spinel monoliths.?Formation and evolution of macroporous morphology were discussed in detail.]]>