Self-supported yttria-stabilized zirconia mesocrystals with tunable mesopores prepared by a chemi-thermal process

Mesoporous mesocrystals are highly desired in catalysis, energy storage, medical and many other applications, but most of synthesis strategies involve the usage of costly chemicals and complicated synthesis routes, which impede the commercialization of such materials. During the sintering of dense ceramics, coarsening is an undesirable phenomenon which causes the growth of the grains as well as the pores hence hinders the densification, however, coarsening is desired in the sintering of porous ceramics to expand the pore sizes while retaining the total pore volume. Here we report a chemi-thermal process, during which nanocrystallite aggregates were synthesized by hydrothermal process and then converted to the product by sintering. Through this strategy, we synthesized mesoporous self-supported mesocrystals of yttria-stabilized zirconia with tunable pore size and the process was then scaled-up to industrial production. The thermal conductivity measurement shows that the mesoporous powder is a good thermal isolator. The monolith pellets can be obtained by SPS sintering under high pressure and the mesoporosity is retained in the monolith pellets. This work features facile and scalable process as well as low cost raw chemicals making it highly desirable in industrial applications. [Display omitted] •A chemi-thermal process was employed to synthesis self-supported zirconia mesocrystals with tunable mesopores.•The process involves hydrothermal synthesis to obtain nanocrystallite aggregates and the following heat treatment.•The heat treatment can be considered as the sintering process of each aggregate.•Coarsening outweighs densification mechanisms to cause the increase of pore size but retain the porous structure.