Application of halohydrocarbons for the re-dispersion of gold particles

Methods to control the dispersion of gold in supported heterogeneous catalysts are very valuable due to the strong nanoparticle size dependence on their activity and selectivity towards many reactions. Additionally, the ability to disperse large, inactive gold nanoparticles to smaller nanoparticles provides an opportunity to reactivate, stabilise and increase the lifetime of gold catalysts making them more practical for industrial applications. Previously it has been demonstrated that the use of gas phase iodomethane (J. Am. Chem. Soc., 2009, 131, 6973; Angew. Chem., Int. Ed., 2011, 50, 8912) was able to re-disperse gold from >20 nm particles to dimers and trimers. In the current work, we show that this technique can be applied using less hazardous halohydrocarbons treatments, both in the gas phase and the liquid phase. The ability of these individual halohydrocarbons to re-disperse gold as well as the extent to which leaching occurs is assessed.