In an example of a biologically inspired and nano-engineered catalyst, researchers at RMIT University (Melbourne, Australia; www.rmit.edu.au) have developed ceramic catalyst particles with a porous network organized hierarchically, where one chemical reaction takes place within larger pores, while a second transformation occurs in the smaller pores.
The porous ceramic framework, which the researchers say is inexpensive to manufacture, allows a precise way of performing multiple reactions in a set sequence. Also, the compartmentalization of the active-site environments and substrate channeling protects the active sites from impurities, allowing the catalyst to be used to convert a highly impure feedstock, such as used cooking oils, into a valuable product, such as biodiesel fuels.
To achieve the transformation from mixed feedstock to diesel fuel, the macropores of the catalyst material are selectively functionalized with a sulfated zirconia solid-acid coating, while the smaller mesopores are selectively functionalized with MgO solid-base nanoparticles. Co-lead investigator Karen Wilson, of RMIT, said the new catalyst design mimicked the way that enzymes in human cells coordinated complex chemical reactions. Previously developed catalysts can perform multiple simultaneous reactions, she says, but “the approaches offered little control over the chemistry and tend to be inefficient and unpredictable.”
The next steps for the RMIT research team are to scale up the catalyst fabrication from grams to kilograms, and to adopt 3D-printing technologies to accelerate commercialization. The team is looking for business partners to create a range of commercially available catalysts for different applications.