Date of Award
Spring 2026
Document Type
Open Access Dissertation
Department
Chemical Engineering
First Advisor
Jochen Lauterbach
Abstract
As the world moves away from carbon-based fuels, new forms of energy storage are required. Sustainable sources of electricity, such as wind, hydro, solar or geothermal energy are effective ways to produce renewable energy but lack the on-demand nature that traditional carbon fuels possess. One option is to use hydrogen instead as it can be combusted like carbon fuels, however hydrogen struggles with low volumetric energy density. As a result, ammonia has been suggested as a hydrogen carrier as it can be decomposed into hydrogen and burned as required. This is useful because ammonia has a significantly higher energy density than hydrogen. New catalysts, though, are required for this process as the catalysts used to make and decompose ammonia work at too high of a temperature and or pressure for use as a sustainable energy carrier.
Here, to combat this, novel ruthenium-based catalysts have been produced for both ammonia synthesis and ammonia decomposition. These catalysts use praseodymium oxide as a support, which is a relatively new support that has only being studied for close to a decade. For ammonia synthesis I have promoted these catalysts with more than forty different promoters, determining that a final mixture of cesium, barium, potassium, and lutetium as promoters are beneficial for the ammonia synthesis reaction. Here, we can produce catalysts that are more active than the traditional ruthenium based and iron-based catalysts. Further, I have sought to understand the reasons that each of these promoters are useful for this reaction. Also, I have doped the praseodymium oxide with dysprosium oxide and showed that this is a beneficial dopant for both ammonia synthesis and ammonia decomposition reactions, causing significant increases in activities for both the forward and backward reaction.
In addition, I have also explored the possibility of using biomass as an energy carrier instead. Biomass as fuel is nothing new and has been used for thousands of years. However, to be used in modern society, it must be a suitable replacement for carbon-based fuels. Pyrolysis is a good option as it converts the biomass into biochar which can be a significant replacement of coal, as it mimics many of the beneficial characteristics that coal has. Under pyrolysis though, there are two other phases that are also produced: the gas phase and the liquid phase. The liquid phase is underutilized compared to the gas phase due to the negative properties that it has. Due to a high water content and it being very acidic, it is difficult to use and store. As a remedy for this, a new method for upgrading using ammonia was produced. Part of this work was to show the feasibility of this process under real biomass conditions, as well as the mechanism for how this process takes place. Overall, this work shows how ammonia can be used in the energy transition away from carbon-based fuels.
Rights
© 2026, Samuel Morgan Drummond
Recommended Citation
Drummond, S. M.(2026). Ammonia for the Green Energy Transition: Synthesis, Decomposition and Usage. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/8918