TiO2 Surface Engineering to Improve Nanostability: The Role of Interface Segregation

Nanoparticle stability against coarsening is one of the keys to allow better exploitation of the properties of nanoscale materials. The intrinsically high interfacial energies of nanoparticles constitute the driving force for coarsening, and therefore can serve as targets to design materials with improved thermal stability. In this study, we discuss the surface engineering of TiO2 nanocatalysts for artificial photosynthesis by exploiting the spontaneous segregation of Ba2+ ions to the interfaces of TiO2 nanocrystals. Ba' is a strong candidate for photoelectrocatalytic reduction of CO, and its effects on interfacial energies lead to a remarkable increase in thermal stability. By using a systematic lixiviation method, we quantified the Ba2+ content located at both the surface and at grain boundary interfaces and combined with microstructural studies to demonstrate that Ba2+ excess quantities meta-equilibrium configurations defined by the Ba2+ content and s establish the fundamental framework for the design of ultrastable direct calorimetric measurements of surface energies and directly impact coarsening of TiO2 nanocatalysts by creating egregation potentials at each individual interface. The results nanocatalysts.