Review of anodic reactions in hydrocarbon fueled solid oxide fuel cells and strategies to improve anode performance and stability

Abstract

Direct utilization of hydrocarbon fuels in solid oxide fuel cells (SOFCs) has drawn special attention for high energy conversion efficiency, low cost, and simple devices. However, when fueled with hydrocarbons, SOFCs encountered great difficulty in both performance and stability, which should be attributed to the sluggish hydrocarbon oxidizing reactions, the severe carbon deposition reactions, and the possible sulfur poisoning reactions in the anode. This review summarizes potential anode reactions in hydrocarbon-fueled SOFCs and discusses the possible anode deactivation mechanisms. Further, various strategies to improve the anode performance and stability are reviewed, including substituting alloys or increasing oxide basicity for nickel-based anodes, adopting oxide anodes, and adding catalyst layers. The advantages and challenges of each strategy are discussed. Special attention is paid on properties and models of novel oxide anodes, of which nano-metal catalysts are in-situ exsolved. The publications concerning SOFC anodes, mainly in recent 5 years, are listed and compared in this article.

Undoped Sr2MMoO6 Double Perovskite Molybdates (M = Ni, Mg, Fe) as Promising Anode Materials for Solid Oxide Fuel Cells

“…The extensive body of research on SOFCs is mostly motivated by the fact that they can efficiently generate electricity over a wide temperature range, do not contain liquid phases, do not require the presence of noble metals and allow for the use of various types of fuels [ 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ]. An SOFC unit is a multilayered structure consisting of an ionic conductor (electrolyte) between two electrodes, an anode and a cathode ( Figure 1 ).…”

Density functional theory analysis for H2S adsorption on pyridinic N- and oxidized N-doped graphenes

“…Following a reforming reaction shown in eqn (1) and (2) , the H 2 gas is extracted from CH 4 , with H 2 O, CO 2 , and CO. 16 Then, hydrogen reacts with oxide ions (O 2− ) coming from the cathode side in fuel cells, as shown in eqn (3) . 17 This O 2− is supplied from O 2 gas in the cathode side. CH 4 + H 2 O ⇆ CO + 3H 2 CH 4 + CO 2 ⇆ 2CO + 2H 2 H 2 + O 2− ⇆ H 2 O …”

Ultralow-Loading Ruthenium Catalysts by Plasma-Enhanced Atomic Layer Deposition for a Solid Oxide Fuel Cell

“…Solid oxide fuel cells (SOFCs) are energy conversion devices with high efficiency and cleanliness. − Furthermore, SOFCs can be operated using conventional fuels, such as hydrocarbons and alcohols, unlike polymer–electrolyte membrane fuel cells (PEMFCs) . Therefore, practical issues associated with hydrogen production and transportation can be mitigated. − While the high operating temperatures (>800 °C) of conventional SOFCs may cause operational problems including rapid thermal degradation, high thermal insulation cost, and limited applicability, low-temperature SOFCs (LT-SOFCs) (operating temperatures <600 °C) may expedite the commercialization of SOFCs. , However, lower operating temperatures trigger an increase in electrochemical losses such as the ohmic loss occurring at the electrolyte and activation loss occurring at electrodes and interfaces between the electrode and electrolyte. Moreover, the direct use of hydrocarbon fuels such as methane instead of hydrogen can cause additional issues such as carbon coking and increased kinetic loss at the anode.…”