Funnel-like macrochannels

Unique porous hierarchy The hierarchically porous materials obtained via this spontaneous self-formation procediu-e possess well-ordered tubular or funnel-like macrochannels with micro/mesoporous walls. The spontaneous self-formation procedure can be optimized by carefully adjusting the synthesis conditions relative to various parameters, such as the central metal atom of the alkoxide, the alkyl group in the alkoxide, hydrolysis ratio, pH, and temperature of the solution. 

On the basis of a series of comprehensive studies, it is found that the key point of this novel synthesis process is the very high rate at which the hydrolyzed metal alkoxides undergo condensation reactions in aqueous solution. A poro-gen mechanism has been proposed to explain the formation of porous hierarchy via the spontaneous self-formation phenomenon [124,139]. The alcohol molecules released suddenly during the hydrolysis and condensation reactions can be considered as porogens in the generation of the funnel-like macrochannels with hierarchically mesostructured porous walls. 

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