High Entropy Oxides as Novel Catalysts for Biomass Hydrodeoxygenation Reactions

• Grant number: 24/20597-6
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: May 01, 2025
• End date: February 28, 2029
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Daniela Zanchet
• Grantee: Eduarda de Castro Flach
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

The growing global energy demand makes it essential to develop new methodologies for producing renewable fuels. Biomass valorization is a sustainable alternative for generating energy from organic materials and the hydrodeoxygenation (HDO) reaction is a key step in this process. HDO reduces the oxygen content in biomass by selectively cleaving C-O bonds in a hydrogen-rich atmosphere using heterogeneous catalysts. HDO of bio-oils is essential for synthesizing stable hydrocarbons suitable for fuel applications. High Entropy Oxides (HEOs) represent a novel class of materials composed of five or more principal elements in equimolar ratios forming an oxide matrix. HEO-based catalysts have exciting potential for HDO due to their ability to combine different metal cations into a stable crystalline phase, allowing adjustments in catalytic properties such as acidity, basicity, and oxygen vacancies. Despite their high thermal stability and resistance to sintering, the application of HEOs in biomass valorization has yet to be explored. This project will focus on synthesizing single-phase spinel HEOs catalysts for HDO reactions, optimizing their acidity and reducibility through composition adjustments and pre-treatments to better control catalytic pathways. Model molecules of representative functional groups of biomass derivatives will be evaluated, such as acetone for ketone-containing oxygenates from biomass. Atomic-scale studies will be essential for understanding structural and electronic properties of the HEO-based catalysts, active sites, and reaction mechanisms. The HEOs will be characterized using conventional methods as well as advanced in situ and operando techniques employing synchrotron radiation. X-ray Absorption Spectroscopy (XAS) will be one of the main techniques used in this work, to investigate the local structure, valence state, disorder, and element interactions.