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Pollucite has been proposed as an ideal candidate material for addressing the critical challenge of the safe trapping of the 137Cs radionuclide. However, its detailed corrosion mechanism remains elusive. In this work, we performed reactive and ab initio molecular simulations to explore the leaching behavior of Cs+ from pollucite glass–ceramics at the initial stage. The nonbridging oxygen ions on the surface are protonated at first, followed by the release of Cs+ associated with these oxygen ions. For the glass phase, the inner Cs+ could leach out due to the interaction with water molecules, whereas only the Cs+ present at the surface leach out for pollucite, confirming its remarkable chemical stability. The hydrolysis of Si/Al–O bonds in pollucite is thermodynamically unfavorable, and Al–O bonds are the weak spots. Moreover, the migration barriers of Cs+ in pollucite were calculated by the climbing image nudged elastic band method, and the high barriers reveal that pollucite immobilizes Cs+ stably. This study paves the way for predicting the long‐term safety of a nuclear waste immobilization repository. [ABSTRACT FROM AUTHOR]

Traditional geopolymer structures benefit from the durability, irradiation resistance, and environmental friendliness, but their brittleness limits their applications where repeated, impactive strains are imparted. This situation may be alleviated if complex structures with tunable geometry can be fabricated, for example, through 3D printing based on direct ink writing (DIW). In this research, SiC whisker/geopolymer (SiCw/GP) composites were fabricated by the DIW for the first time. The rheological behaviors of the SiCw/GP inks and the fracture behaviors of the printed samples were explored. The modified printing inks exhibited non‐Newtonian fluid behavior (shear‐thinning). Subsequently, a series of lightweight architected structures were fabricated, and they revealed how reinforcement and architecture of the printed structures could influence both the strength and toughness of the SiCw/GP composites. [ABSTRACT FROM AUTHOR]

In this paper, monoclinic SrAl2Si2O8 ceramics with porous structures were prepared based on ion‐exchanged geopolymer precursor technique. Micron‐level pores with a homogeneous pore‐size distribution were introduced into the inorganic framework using foaming agents. The results demonstrated that the apparent density, pore‐size distribution and specific surface area of porous geopolymer precursors can be well‐engineered via tailoring the category and concentration of the foaming agent. After being treated at 900°C, hexagonal SrAl2Si2O8 first‐crystallized from the amorphous geopolymer matrix and then gradually converted into monoclinic SrAl2Si2O8 between 1100°C and 1200°C. The resulting monoclinic SrAl2Si2O8 ceramics maintained the porous structures during high‐temperature treatments and exhibited high porosity, specific surface area, and compressive strength. The aforementioned strategy not only achieves monoclinic SrAl2Si2O8 ceramics with well‐defined and robust microstructures, but also provides an alternative route to prepare other porous ceramics, with potential applications in fields of high‐temperature filters, adsorbents, and heterogeneous catalysis. [ABSTRACT FROM AUTHOR]