Electrically-Driven Catalytic Alkane Dehydrogenation As A Means For  Renewable Hydrogen Fuel

Nygren, Ariana

Undergraduate Honors Thesis

Electrically-Driven Catalytic Alkane Dehydrogenation As A Means For Renewable Hydrogen Fuel Public Deposited

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Citeable URL: https://scholar.colorado.edu/concern/undergraduate_honors_theses/76537305s

Abstract

The increasing threat of the burning of fossil fuels and its contribution to global warming has led to the increasing focus on a new means for the utilization and storage of clean and renewable energy1,2. Hydrogen fuel cells are at the forefront of research in this field3. In the chemistries of such fuel cells, the only products of these devices are energy is water4. However, with the use of hydrogen gas, several safety drawbacks are found: high flammability, invisible flame, and ability to embrittle metal5, therefore an improved way of storage that does not involve the gas itself has been sought after. One proposed solution has been to store the hydrogen in chemical bonds6,7. Previous research has shown an effective method being through a catalytic dehydrogenation reaction of alkanes to produce hydrogen6,7. This reaction has been performed at high temperatures7,8, which is inapplicable on a larger scale. The aim of my research is to perform acceptorless dehydrogenation of alkanes at ambient temperatures to produce and release hydrogen from alkane chemical bonds. An iridium pincer catalyst with a sigma-donating cyclic N-heterocyclic carbene containing ligand, called the CCC ligand, was used to perform the reaction8. To do so, a reducing agent in dimeric form, [N-DMBI]2, was used to reduce the iridium pincer catalyst so it can be activate for the dehydrogenation reaction. Through proving this concept, the same reaction can then be done using electrochemical methods. Two reactions were set up containing the iridium CCC-pincer complex and octane, one with the N-DMBI and one without. The content of octane and 1-octene in each reaction was analyzed and quantified using flame ionization detector gas chromatography (GC-FID). In doing so, both reaction mixtures showed the presence of 1-octene. However, the reaction mixture containing N-DMBI had a greater amount of 1-octene than without, indicating the reduction of the iridium metal center by the N-DMBI.

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