XAS time-resolved phase speciation of Cu-based Layered Double Hydroxides to ethanol dehydrogenation

• Grant number: 17/13821-3
• Support type: Scholarships abroad - Research Internship - Doctorate
• Effective date (Start): October 01, 2017
• Effective date (End): September 30, 2018
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Celso Valentim Santilli
• Grantee: Rodrigo Morais Menezes dos Santos
• Supervisor abroad: Briois Valerie
• Home Institution: Instituto de Química (IQ). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil
• Local de pesquisa : SOLEIL Synchrotron, France
• Associated to the scholarship: 15/23410-5 - Copper-based layered double hydroxides for hydrogen production and other value-added products, BP.DR

Abstract

Layered Double Hydroxides (LDH) and their thermal decomposed products have received much attention in the past decades due to important applications in catalysis. LDH have been advantageous in catalysis due to the uniform distribution of metal cations at atomic level, and upon thermal treatment, they give rise to highly dispersed and stable metallic nanoparticles supported in oxide matrix. Cu-based LDH catalysts are very active for ethanol dehydrogenation reaction (EDR), however the role of metastable intermediate species in the catalyst activity is not completely solved. Traditionally, Cu0 species has been described as the active phase for EDR, although recent studies have shown that Cu+ or an optimal Cu+/Cu0 ratio, can improve the activity and selectivity. The X-ray absorption spectroscopy (XAS) time-resolved technique, during catalyst activation and reaction (in operando) will be applied for solving the questions raised by the role of the different active species formed in the catalytic steps. During the BEPE we intend to use the excellent time resolution of the XAS technique to access all the zinc and copper species involved during thermal decomposition, activation and reaction. The identification of intermediate species together with the concentration profiles evolution of all species should give conclusive information to improve the conversion and selectivity.