(668d) Improving Long-Term Stability of SOFC Anodes: First Principles Approaches toward Carbon-Tolerant Alloy Electrocatalysts

Solid Oxide Fuel Cells are solid-state devices that generate electricity by electrochemically oxidizing various fuels such as hydrogen, CO, and hydrocarbons. One of the main issues associated with the direct operation of SOFC using hydrocarbons is that conventional anode catalysts, such as Ni on yttria-stabilized zirconia (YSZ), deactivate due to the formation of carbon deposits. The carbon-induced anode deactivation can be alleviated by increasing the feed steam concentration. However, this approach is not optimal for SOFCs since a higher inlet steam concentration results in a lower energy density.

We have utilized Density Functional Theory (DFT) calculations to study carbon chemistry on Ni and Ni-containing alloy electrocatalysts. The main objective of these studies was to develop molecular insights regarding carbon poisoning on Ni and to utilize this molecular information to identify possible carbon-tolerant alternative anodes to Ni. The DFT calculations showed that certain Ni surface alloys had lower tendencies towards carbon poisoning compared to monometallic Ni. The identified alloy catalysts have been synthesized and characterized. The potential utility of these alloy materials as carbon-tolerant SOFC anodes was experimentally demonstrated.