
Research Summary:
Millions of tons of biodiesel per year are industrially produced via the transesterification of various pretreated bio-derived feedstocks. While this fuel has improved combustion, improved emissions, and is of course renewable, it is not without its disadvantages; low energy content and poor cold flow properties are among its main detractors. Additionally, prior to its conversion to biodiesel, substantial amounts of fatty acid must be extracted from the raw feedstocks and essentially discarded, as the most popular industrial production methods require stringent feed composition specifications. These fatty acids can be subsequently deoxygenated via thermal decomposition or palladium catalysis to form their alkane derivatives, increasing the energy content and resolving any cold flow issues. Published decarboxylation studies have focused on palladium metal supported on microporous, amorphous activated carbon, which is commercially available but ill-defined. These catalysts have shown decent one-time activity, but considerable consequent deactivation.
In this research, well-defined supported palladium nanoparticles will be synthesized and tested for decarboxylation activity and recyclability. Using an array of spectroscopic, microscopic, and spectrometric characterization techniques, the deactivation of these catalysts will be detailed. Modifying different well-defined solid mesoporous supports (SBA, CMK, MCF) via pre-oxidation or surface silane functionalization will be studied, and the subsequent effects on activity and stability will be measured. Changes in nanoparticle morphology, palladium oxidation state, support structure, organic loading/deposition, active surface area and dispersion will provide insight into the deactivation mechanism of decarboxylation catalysts. Applying this knowledge to the design and development of a new catalyst could provide a cost-effective and sustainable option for converting renewable fatty acids and fatty acid derivatives into next generation fuels.