Ramallo, J. I., Gonzalez, R. I., Fuertes, M. C., & Bringa, E. M. (2025). Mechanical properties of nanoporous TiO2: Atomistic simulations and experiments. Journal of the American Ceramic Society, e70333. https://doi.org/10.1111/jace.70333

Abstract: Nanoporous anatase TiO₂, widely used in catalysis and sensing due to its high specific area, is usually exposed to mechanical solicitations in service. Several studies have examined how nanoscale porosity affects elastic modulus and hardness; however, the deformation mechanisms, as well as the role of porosity and pore radius in mechanical properties, remain unclear. In this work, the mechanical response of nanoporous anatase is studied through nanoindentation and molecular dynamics simulations using reactive interactions. Virtual samples with varying porosities and pore radii are uniaxially loaded along two high-symmetry directions. Results show that the elastic modulus for both experiments and simulations decreases linearly with porosity. In addition, plastic yield stress decreases with increasing porosity, consistent with nanoindentation experiments. Elastic deformation is followed by shear localization and directional amorphization as the preferred plasticity mechanism. Regarding the pore structure collapse, it was highly anisotropic due to localized directional amorphization. Moreover, the evolution of porosity during compression is well described by a sigmoidal model. This deformation without dislocation activity is consistent with previous studies on materials with covalent and partially ionic bonds. The proposed mechanism helps prevent brittle fracture and enables property tailoring for technological applications.