Pore structure regulation of hierarchically porous TiO2 ceramics derived from printable foams

Titanium dioxide (TiO2) is widely used as pollutants degradation material because of the effective photocatalytic capacity, while broad applications are limited due to their traditional forms for application involving as-received powders or coating on carrier. Herein, a novel method for hierarchically porous TiO2 ceramics with designable pores has been put forward, that is direct ink writing of printable particle-stabilized foams. The uneven particle distribution or low solid loading caused weak areas of particle self-assembly on pore wall during foaming, leading to fracture to form interconnected pore structure once grain growth happened during following sintering process. Both open and closed pore structure could be well controlled by adjusting powder composition, sintering temperature and solid loading. The prepared porous TiO2 ceramics possess homogeneous pores, high porosity of 81.76%, bulk density of 0.78 g/cm3 and compressive strength of 11.8 MPa, which can be readily exploited in filter component, catalyst supports, biological scaffolds, especially those with sophisticated shape.