Electrochemical and Operando Spectroscopic Studies of Sr₂Fe_1.5Mo_0.5O_6‐δ Anode Catalysts in Solid Oxide Fuel Cells Operating with Direct Alcohol Fuels

Abstract

A combination of operando Raman spectroscopy and chronoamperometry was used to examine the carbon tolerance of Sr2Fe1.5Mo0.5O6‐δ (SFMO) electrode catalysts when operating with direct methanol and ethanol fuels in solid oxide fuel cells (SOFCs). Chronoamperometry studies revealed that these devices could maintain a steady power density output under typical SOFC operating conditions. High‐temperature Raman measurements of SFMO coupons exposed to methanol and ethanol (and their gas phase pyrolysis products) showed the presence of spectroscopic features associated with ordered and disordered forms of graphitic carbon. However, once SFMO was employed as an anode in an electrolyte‐supported SOFC, the graphite features disappear implying that these materials are not susceptible to carbon accumulation in functioning devices. These electrochemical and operando Raman measurements provided insight into SFMO's ability to act as an effective anode catalyst for SOFCs operating with direct alcohol fuel sources.

High Temperature X-ray Absorption Spectroscopy of the Local Electronic Structure and Oxide Vacancy Formation in the Sr2Fe1.5Mo0.5O6−δ Solid Oxide Fuel Cell Anode Catalyst

“…Previous work conducted by the authors utilized a direct correlation of voltammetry with in operando Raman spectroscopy to exhibit that the perovskite anode, Sr 2 Fe 1.5 Mo 0.5 O 6−δ (SFMO), is capable of operating with alcohol fuels while completely resisting detrimental graphite deposits . A key finding of this work is that SFMO was capable of operating with ethanol, which is known to form significant graphite deposits throughout the anode during device operation which are brought upon by C 2 fuel pyrolysis products . In the present work, SFMO will be explored to understand the roles that the Fe and Mo atoms, in this crystal structure, play in fuel oxidation mechanisms and afford this material its fuel tolerance capabilities seen in this previous work.…”

Advanced Ru‐Infiltrated Perovskite Oxide Electrodes for Boosting the Performance of Syngas Fueled Solid Oxide Fuel Cell

“…[7][8][9][10][11] Developed anode materials are often used to solve this problem. [7,[12][13][14][15] Although traditional electrode, such as Ni-YSZ cermet anode, shows great oxide-ion conductivity at high temperature, it has poor redox stability and always suffers from carbon deposition with hydrocarbon fuels. [16][17] Hence, alternative anode materials are still dominate issue, especially for hydrocarbon.…”

“…Carbon deposited on the electrodes will cover the catalytic active sites and restrain the gas transportation, which could cause performance degradation, cracks in the micro-constructure or even collapse of the cell. [7][8][9][10][11] Developed anode materials are often used to solve this problem. [7,[12][13][14][15] Although traditional electrode, such as Ni-YSZ cermet anode, shows great oxide-ion conductivity at high temperature, it has poor redox stability and always suffers from carbon deposition with hydrocarbon fuels.…”

“…Although a large amount of experimental data for electrochemical oxidation of syngas fuel are available, the carbon deposition (coking) is still predominantly a severe issue in the application of SOFCs. Carbon deposited on the electrodes will cover the catalytic active sites and restrain the gas transportation, which could cause performance degradation, cracks in the micro‐constructure or even collapse of the cell [7–11] . Developed anode materials are often used to solve this problem [7,12–15] .…”

Vanadium-Doped Strontium Molybdate with Exsolved Ni Nanoparticles as Anode Material for Solid Oxide Fuel Cells

“…Solid oxide fuel cells (SOFCs) are capable of converting chemical energy of various fuels including hydrogen, syngas, and hydrocarbon directly into electricity with high efficiency and low pollution emissions. − The fuel-converting process takes place at SOFC anode, where the fuel combines with oxygen ions to form H 2 O and CO 2 meanwhile releases electrons. Nickel-yttria-stabilized zirconia (Ni-YSZ) cermet is the most commonly used anode material, in which YSZ serves as an oxygen ionic conductor, while Ni serves as an electronic conductor and electrocatalyst. − It is well known that such cermet suffers from carbon deposition, sulfur poisoning, and redox instability, all of which can lead to serious degradation in performance. , Thus, it is imperious to develop alternative SOFC materials with high catalytic performance and stability for fuel oxidation reactions.…”