NSF-DFG Echem: Understanding the Mechanism of Urea Oxidation on Nickel-Based Electrocatalysts

• Applicant: Professor Richard Kramer Campen, Ph.D.
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation ; Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 460536565

This project examines electrochemical oxidation of urea to obtain fundamental information about its reaction mechanism and kinetics and the influence of the nature and structure of the catalyst. Urea oxidation is central to a large number of technological applications including municipal and agricultural wastewater treatment, remediation of fertilizer run-off harmful to aquatic life, ammonia synthesis, hydrogen production, and electricity production in direct urea fuel cells. A comprehensive scientific understanding is crucial to guiding engineering development of effective urea reaction devices to bring these technologies to fruition. This research effort brings together leading researchers from the United States and Germany and applies a unique blend of experimental and theoretical methods to the study of urea oxidation.Only nickel and nickel-based catalysts are effective for electrochemical oxidation of urea. Research to develop new urea catalysts have examined a wide range of modifiers. This study focuses on just three catalysts: nickel as a baseline catalyst; nickel-iron, a catalyst highly active for both urea oxidation and oxygen evolution; and nickel-chromium, an emerging, highly active catalyst with the prospect for corrosion resistance.Electrooxidation of urea will be studied by density functional theory calculations, vibrationally and electronically resonant sum frequency spectroscopy, and electrochemical measurements of reaction rate and product distributions. The active form of the Ni oxide catalyst exists in different phases and oxidation states depending on potential and history (age/preparations method, etc.), which are critical to urea oxidation. This combined electrochemical, spectroscopic, and computational approach allows us to study these structural changes and how they affect the urea reaction mechanism, reactivity, and effectiveness of nickel, nickel-iron, and nickel-chrome catalysts. The outcomes of this research will greatly advance the scientific understanding of urea electrooxidation, about which little is known, and establish a foundation in the wider field of electrocatalysis regarding electrochemical reactions on oxide surfaces and on surfaces that undergo redox reactions during reaction.

• DFG Programme: Research Grants
• International Connection: USA
• Cooperation Partners: Professor Eric Stuve, Ph.D.; Professorin Dr. Linney Árnadóttir