Anatase TiO2 single crystals with a large percentage of reactive facets

Single crystals of titanium dioxide (TiO2), with highly reactive surfaces, show promise for energy and environmental applications. Unfortunately, the highly reactive surfaces tend to disappear during crystal growth as a result of the minimization of surface energy. Most available samples of anatase, a naturally occurring crystalline form of TiO2, are therefore dominated (to over 90%) by thermodynamically stable {101} facets, rather than the more reactive {001} type. Hua Gui Yang et al. use hydrofluoric acid treatment of anatase TiO2 to remedy this situation. Based on theoretical predictions, they synthesized uniform anatase TiO2 single crystals containing 47% of the reactive {001} facets. This work may pave the way for the more general use of non-metallic atoms as surface controlling agents.