Catalysis Science & Technology Blog

Carbon dioxide is one of the major contributors to global climate change and there are mounting concerns over the emission of such greenhouse gases.  Research into the reduction of CO₂ emissions is widespread.  The development of technologies to generate renewable energies is the most desirable way in the long term.

However, at present, these technologies are not able to replace existing fossil fuel-based power generation. Recent innovations have made the photocatalysis technology a potentially promising alternative.

Now, in this Catalysis Science & Technology Hot Article, Pratim Biswas et al., from Washington University in St. Louis, USA describe, for the first time, the rapid and direct synthesis of nanostructured copper-doped titania–silica (Cu–TiO₂–SiO₂) composite particles for CO₂ photoreduction using a furnace aerosol reactor (FuAR). This method is both simple and effective, with an extremely short processing time ( several seconds).

Read the article for free here.

Rapid synthesis of nanostructured Cu–TiO2–SiO2 composites for CO2 photoreduction by evaporation driven self-assembly
Wei-Ning Wang, Jinho Park and Pratim Biswas
Catal. Sci. Technol., 2011, Advance Article, DOI: 10.1039/C0CY00091D

In this new Catalysis Science & Technology Hot Article, Piet van Leeuwen et al. describe their investigation into the H-transfer activity of secondary phosphine oxide (SPO) complexes.  The key feature is the heterolytic transfer of the two hydrogens as H+ to the O of P=O, and H- to the metal. They found that rhodium SPO complexes yielded active and enantioselective catalysts, which was supported by DFT calculations.

SPOs act as ligands in their trivalent phosphinous acid tautomeric form. Their metal-to-phosphorus bond is comparable in strength to that of phosphines and they are often used as monodentate ligands, but more often as bidentate and tridentate ligands towards transition metals connected via their oxygen atoms by protons or hard metals.

Read more about these new ligands for free until 29th March 2011, here.

SPOs as new ligands in Rh(III) catalyzed enantioselective transfer
hydrogenation
Pascal M. Castro, Henrik Gulyas, Jordi Benet-Buchholz, Carles Bo,
Zoraida Freixa and Piet W. N. M. van Leeuwen
Catal. Sci. Technol., 2011, Advance Article, DOI:10.1039/C0CY00022A

As the natural supplies of fossil fuels quickly deplete due to the increasing demands of modern society, industrial chemistry needs to find alternative sources for the essential building blocks on which it relies upon. New raw material deriving from sustainable sources need to be exploited to diminish the use of petrol-based products.

A viable alternative has been investigated by Jones et al., whose UK-based research focused on the catalytic conversion of easily produced ethanol into 1,3-butadiene, a common precursor in the industrial production of rubber. The groups developed a silica-supported multi-metallic system that using cooperative catalysis drives the transformation of ethanol into acetaldehyde and through a number of other intermediates, ultimately produces 1,3-butadiene.

The catalysts could be easily prepared mixing slurries of water-soluble salts of the desired metals with silica of different porosity, followed by water evaporation and calcination in air at different temperatures.

Several combinations of metals and silica supports were tested, finding the ZnO:ZrO₂ couple to provide the higher conversions and selectivity for the diene (38 %) in 1 to 3 hours, although with relevant amounts of ethene produced as a side product. Even better selectivity could be achieved introducing extra acetaldehyde in the reaction. When ethanol was fed into the system in these conditions the selectivity for 1,3-butadiene increased to 66 %. A tri-metallic system based on zinc, copper and zirconium was also investigated, providing higher conversions but lower selectivity.

Find more in the original article.

Investigations into the conversion of ethanol into 1,3-butadiene
Matthew D. Jones, Callum G. Keir, Carlo Di Iulio, Ruth A. M. Robertson, Cliff V. Williams and David C. Apperley
Catal. Sci. Technol., 2011, Advance Article
DOI: 10.1039/C0CY00081G, Paper