Investigation of carbon formation on Ni/YSZ anode of solid oxide fuel cell from CO disproportionation reaction

Abstract

A challenge in the operation of solid oxide fuel cells (SOFCs) with hydrocarbon fuels is carbon deposition on the nickel/yttria-stabilized zirconia (Ni/YSZ) anode. This paper investigated the carbon formation on Ni/YSZ anode of solid oxide fuel cell (SOFC) due to CO disproportionation reaction. The steady-state rates of carbon formation under different CO/CO2 gas compositions were measured at temperature range from 600°C to 800°C. Experimental results showed that the steady-state rate of carbon formation caused by CO disproportionation reaction cannot solely be expressed with temperature or CO/CO2 gas ratios. A kinetic model divides the CO disproportionation reaction into several stepwise reactions, among which one of the stepwise reactions, namely, the C‐O bond cleavage reaction, is considered as the rate-limiting step of the overall reaction. This kinetic model fits very well with the experimental results. Based on the kinetic model and experimental data, a steady-state rate equation of carbon formation in the process of CO disproportionation reaction was derived at the temperature from 600°C to 800°C on Ni/YSZ anode of SOFCs.