My watch list
my.chemeurope.com  
Login  

Titanium dioxide nanoreactor

25-Feb-2013

HZB

The nanoparticles crystallize in a polymer network at room temperature.

Now, Dr. Katja Henzler and a team of chemists at the Helmholtz Centre Berlin have developed a synthesis to produce nanoparticles at room temperature in a polymer network. Their analysis, conducted at BESSY II, Berlin's synchrotron radiation source, has revealed the crystalline structure of the nanoparticles. This represents a major step forward in the usage of polymeric nanoreactors since, until recently, the nanoparticles had to be thoroughly heated to get them to crystallize. The last synthesis step can be spared due to the special environment inside the PNIPAM network.

The Henzler team's polymeric nanoreactors consist of a polystyrene core surrounded by a network of PNIPAM chains. A titanium compound was added to an ethanolic solution of the polymer colloids, which did trigger the formation of small titanium dioxide particles within the PNIPAM network. The BESSY II experiments showed that the chemists were able to control the speed of these processes while at the same time affecting the quality of the nanocrystals that had formed.

Using the novel combination of x-ray microscopy and spectroscopy (NEXAFS-TXM, U41-SGM) at BESSY II, Henzler and the microscopy team were able to show that the nanoparticles are homogeneously distributed over the polymeric nanoreactors. The researchers examined their samples in a cryogenic aqueous environment, which prevents artifact formation due to sample drying. Their analysis showed that the nanoparticles have a crystalline structure. "The nanocrystals have a tetragonal anatase structure and this crystalline structure is a key to their catalytic performance.

Additionally, our new analytic method allows us to control the quality of the synthesized particles so that we can optimize them for relevant applications," says Katja Henzler.

Facts, background information, dossiers
More about Helmholtz-Zentrum Berlin für Materialien und Energie
  • News

    Solar hydrogen production by artificial leafs

    Metal oxides are promising candidates for cheap and stable photoelectrodes for solar water splitting, producing hydrogen with sunlight. Unfortunately, metal oxides are not highly efficient in this job. A known remedy is a treatment with heat and hydrogen. An international collaboration has ... more

    Optical control of magnetic memory

    A research team at Helmholtz-Zentrum Berlin (HZB) has shown for the first time how laser modulation of magnetic properties in materials is influenced by thermal effects and how the process occurs under moderate experimental parameters. At the same time, the scientists discovered a previousl ... more

    New model for bimolecular reactions in nanoreactors

    Theoretical physicists have devised a mathematical model of two different molecules reacting within so called nanoreactors that act as catalysts. They gained surprising new insights as to what factors promote reactions and how to control and select them. The model is relevant for a wide ran ... more

Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE