Direct Visualization of Independent Ta Centers Supported on Two-Dimensional TiO Nanosheets.

Highly dispersed, supported oxides are ubiquitous solid catalysts but can be challenging to characterize with atomic precision. Here, it is shown that crystalline anatase TiO nanosheets (∼5 nm thick) are ideal supports for imaging highly dispersed active sites. Ta cations were deposited by several routes, and high-resolution high angle annular dark-field scanning transmission electron microscopy was used to determine the location of Ta with respect to the TiO lattice and quantify Ta-Ta distances.

Strain-Induced Segregation in Bimetallic Multiply Twinned Particles.

We analyze the possibility of strain-induced segregation in bimetallic multiply twinned particles by an analytic first-order expansion within a continuum model. The results indicate that while the change in free energy may be small, there will be a noticeable segregation of larger atoms to the external surface and smaller ones to the core, which could have interesting effects when such nanoparticles are used as heterogeneous catalysts.

Segregation in bimetallic nanoparticles.

Bimetallic nanoparticles are of interest due to their physical and chemical properties, which differ from their monometallic counterparts, and are dependent on size, composition and structure. Their unique chemical and physical properties make them useful in many optical, electronic and catalytic applications. In this perspective article we discuss segregation in bimetallic nanoparticles and highlight a recent analytical model based on minimization of energy.