The crystallinity, textural characteristics, optical absorption properties, as well as the photocatalytic hydrogen production activities of three-dimensional interconnected mesoporous In(2)O(3)/Ta(2)O(5) composites were investigated as functions of In(2)O(3) content (x) and calcination temperature (T). The results show that the incorporation of In(2)O(3) endows intimate heterostructured junctions in the composites and significantly improves the thermal stability of mesopores. With increasing x, the as-prepared composites possess similar textural properties and continuously increased light absorbencies, but a maximum heterojunction area, and thus, the optimal value for the average hydrogen evolution rate ( ̅Q(H(2))) as well as the special surface hydrogen evolution rate ( ̅Q(H(2),S)) at x=20%. For the 20% In(2)O(3)/Ta(2)O(5) composites prepared at different T, the special surface area decreases and the pore size enlarges with increasing T from 450 to 650 °C. An obvious collapse of mesopores accompanying with remarkable crystallization occurs at 750 °C. The highest [Formula: see text] occurs on the sample calcined at 550 °C, while the optimal ̅Q(H(2),S) appears at 750 °C. This suggests that good charge carrier separation and transport properties, rapid mass transfer of reactants and gases desorption are as important as large surface area and high crystallinity for the photocatalysts.
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