Pore structure of γ-Ga2O3–Al2O3 particles prepared by spray pyrolysis

Calcination of the precursor particles obtained by the spray pyrolysis of an aqueous solution of Ga(NO3)3 and Al(NO3)3 in the presence of HNO3 gave γ-Ga2O3–Al2O3 solid solutions and their pore structures were examined. The temperatures of the sequential ovens and flow rates of air as an entrainer of the mists for spray pyrolysis affected the pore structure of the products, although the pore systems were developed during the subsequent calcination stage. These products had two types of pore structures and origin of these pore structures was discussed on the basis of the core–shell structure of the spherical particles of the products. Effects of the concentrations of metal nitrates and HNO3, and of the addition of urea to the starting solution in place of HNO3 upon that pore structure of the products were also examined.

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► The γ-Ga2O3–Al2O3 particles were obtained by spray pyrolysis and subsequent calcination.
► Condition for spray pyrolysis affected the pore structure.
► The γ-Ga2O3–Al2O3 solid solutions had two types of pore structures.