Theory Driven Catalysts Design for Hydrogenation Reactions in Solid Oxide Electrolyzer

Abstract

Hydrogenation reactions are essential processes in the chemical industry, giving access to a variety of valuable compounds. CO2 and N2 can be transformed into carbonates and NH3 through hydrogenation reactions. Metal oxides supported metals/alloys are the most investigated catalytic materials in heterogeneous electrochemical catalysis. The strong metal-support interaction (SMSI), which determines the catalytic activity, largely depends on chemical conditions of the support and particle size of dispersed metal nanoparticles (NPs). In this work, we studied the SMSI in doped CeO2 supported noble metal NPs systems and their activities for CO2 and N2 hydrogenation reactions in solid oxide electrolyzer. By using a combination of high-throughput density functional theory (DFT) calculations and electrochemical measurements in solid oxide electrolyzer, we developed highly active catalysts for CO2 and N2 hydrogenation reactions.The reactions of CO2 and N2 hydrogenation normally require large energy input because both CO2 and N2 are quite stable and inert molecules with strong chemical bonds and low polarizability. The adsorption of CO2 and N2 molecules on metal-oxide composite surfaces is normally quite weak, which results in large energy barriers for their activation processes. We performed DFT calculations to determine the key properties for selected doped CeO2 supported noble metal NPs systems to achieving high performance under solid oxide electrolyzer operating conditions. The predictions were further confirmed by the experiments. The highly predictive DFT calculations played a great role in determining the development of electrochemical catalysts for hydrogenation and reactions. Atomic-level materials properties and reaction pathways based on different reaction mechanisms from DFT paved the way for searching for highly active catalysts. The experimental evidence indicated that it is applicable to several hydrogenation reactions.