11.12.2024
Doctoral thesis on electrocatalytic conversion of glucose and xylose into value-added chemicals
M.Sc. (Tech.) Jay Pee Permejo Oña’s doctoral thesis in Process and Energy Technology (Industrial Chemistry and Reaction Engineering) will be put forth for public defence at Faculty of Science and Engineering at Åbo Akademi University.
The thesis is entitled Electrocatalytic conversion of glucose and xylose into value-added chemicals.
The public defence of the doctoral thesis takes place on Friday 20 December 2024 at 12PM in Auditorium Helikon, Arken, Tehtaankatu 2, Turku. You can also follow the defence online. Professor Têko W. Napporn, CNRS University of Poitiers, France, will serve as opponent and Professor Henrik Grénman, Åbo Akademi University, as custos.
Summary
This doctoral thesis focuses on the electrocatalytic conversion of glucose and xylose, two main components of wood biomass, into higher-value compounds. The electrocatalytic reactions were carried out by applying an electrical voltage on the catalyst immersed in the sugar solution within a certain time period. These electrochemical reaction systems allow chemical transformations at ambient conditions that are directly applicable to water-rich biomass feedstocks. These processes can also potentially be powered by renewable electricity, which serves as basis for sustainable production of value-added compounds.
In this work, both the electrocatalytic hydrogenation and oxidation of glucose and xylose were investigated. Electrochemical hydrogenation of glucose and xylose can produce sorbitol and xylitol, respectively, which are widely employed as artificial sweeteners. Hydrogen is derived directly from the water solvent, thereby eliminating the need for costly high purity hydrogen gas. From the experimental results, the rate of sugar hydrogenation was observed to be influenced by the chemical nature and surface properties of the metal catalyst. Among the bulk metal catalysts screened, a copper catalyst with a rough surface was observed to be the most active catalyst towards electrocatalytic hydrogenation and the reaction rate can be improved by increasing the catalyst surface area.
The electrocatalytic oxidation of glucose and xylose yielded primarily gluconic and xylonic acids, which are used as additives in the food and pharmaceutical industries. Oxidative reactions were carried out under alkaline conditions using gold nano-catalyst supported on mesoporous Sibunit carbon. Sugar oxidation rates were influenced by the gold cluster size, reaction temperature and pH. The reaction mechanism of sugar electro-oxidation was investigated using grand canonical density functional theory (GC-DFT) which showed the role of co-adsorbed hydroxide ions in improving the selectivity towards the formation of the sugar acids.
Using the most active catalysts observed in this work, the simultaneous hydrogenation and oxidation of xylose was demonstrated to be possible via paired electrolysis, which gave a foundation for process intensification. Furthermore, this work provided a basis for catalyst development and selection of reaction conditions for the electrocatalytic conversion of sugars towards the sustainable production of value-added chemicals from wood biomass.
Jay Pee Permejo Oña can be reached by phone +358 46 842 2913 or email jay.ona@abo.fi.
The doctoral thesis can be read online through the Doria publication archive.
Click here for a press photo of the doctoral student.
Instructions for following the doctoral defence remotely:
To follow the defence, you need the Zoom software or the Google Chrome browser. You do not need to create a Zoom account to follow the defence. If you install the application, you participate by clicking on the meeting link, after which you should allow the link to open in the Zoom app.