Improving Carbon Tolerance of Ni Catalysts and Electrocatalysts

Introduction Steam reforming is a process that converts hydrocarbon fuels into hydrogen and oxygenated carbon species. This process is important for catalytic hydrogen production and for direct electrochemical reforming of hydrocarbons over high temperature fuel cells, such as Solid Oxide Fuel Cells (SOFCs). One of the main problems associated with the process is that conventional reforming (electro)catalysts, such as Ni supported on oxides, deactivate due to carbon poisoning. We have utilized Density Functional Theory (DFT) calculations to study carbon chemistry on Ni and Ni-containing alloys.[1-3] The DFT calculations showed that a number of Ni surface alloys had lower tendencies towards carbon poisoning compared to monometallic Ni. The identified alloy catalysts were tested in steam reforming of methane, propane, isooctane, and other hydrocarbon fuels. These catalysts were also tested as anodes in SOFCs. The alloy (electro)catalysts showed significantly improved performance compared to monometallic Ni.[1-3] We will also discuss the underlying physical characteristics of the alloy catalysts that are associated with the improved performance of the alloy catalysts. In this discussion we will focus on the analysis of the electronic structure of the alloy catalysts, and we will relate the alloy electronic structure to the performance.