Effects of Manganese Oxide Addition on Coking Behavior of Ni/YSZ Anodes for SOFCs

Abstract

Solid oxide fuel cells with Ni-MnO/yttria-stabilized-zirconia (YSZ) tricomposite anode supports were fabricated with different MnO concentrations, and the coking tolerances and catalytic activities were investigated in wet CH 4 atmosphere. Ni 0.9 (MnO) 0.1 /YSZ (10MnO) anode support cell exhibited a maximum power density of 210, 354, 505, and 620 mWcm -2 at 700, 750, 800, and 850°C, respectively, in H 2 . Moreover, a maximum power density in wet CH 4 reaches 504 mWcm -2 at 800°C; while the Ni/YSZ cell showed poorer performances. The coking tolerance improved with an increase in their MnO content, and the 10MnO anode showed the highest tolerance. 10MnO exhibited stable performance for more than 40 h in wet CH 4 without undergoing deactivation. Furthermore, it showed negligible coke formation of 0.0045 g of coke per catalyst, during testing under steam reforming-like conditions at a steam-to-carbon (S/C) ratio of 1. Outlet gas chromatography analysis indicated that MnO suppresses CH 4 cracking, while only minimally lowering the catalytic activity of steam reforming. Thus, it can be inferred that MnO promotes the adsorption of steam and oxygen on the reaction sites, owing to its high basicity and oxygen storage capacity. The increase in the local S/C and oxygen-to-carbon ratios suppresses CH 4 cracking and promotes coke gasification.

Ruddlesden–Popper Oxide (La0.6Sr0.4)2(Co,Fe)O4 with Exsolved CoFe Nanoparticles for a Solid Oxide Fuel Cell Anode Catalyst

“…The first intercept value of the x-axis in the electrochemical impedance spectroscopy (EIS) graph represents the Ohmic resistance (R Ω ) associated with the LSGM electrolyte support and the interfacial contact between the electrolyte and the electrode. [15,40] In addition, the difference value between the two x-intercepts is the polarization resistance (R p ) related to surface oxygen exchange and charge transfer. [15,40] Using the equivalent circuit inserted in Figure S8, Supporting Information, the R p could be deconvoluted into two impedances, R 1 (high frequency, charge transfer reaction) and R 2 (low frequency, diffusion steps in electrode reaction).…”

“…[15,40] In addition, the difference value between the two x-intercepts is the polarization resistance (R p ) related to surface oxygen exchange and charge transfer. [15,40] Using the equivalent circuit inserted in Figure S8, Supporting Information, the R p could be deconvoluted into two impedances, R 1 (high frequency, charge transfer reaction) and R 2 (low frequency, diffusion steps in electrode reaction). [41,42] The fitted values of each resistance are listed in Table S2, Supporting Information.…”

Optimization of the Perturbation Amplitude for Impedance Measurements in a Commercial PEM Fuel Cell Using Total Harmonic Distortion

“…It has been applied in a broad range of application fields 1. For instance it has been extensively used in the study of fuel cells 4–7, batteries 8–12, supercapacitors 13–17, electrochemical reaction kinetics 18–21, coatings 22–25, corrosion 26–29 and electrochemical sensors 30–33. This electrochemical measurement technique has also been used in fields that are not historically linked to electrochemistry as enzymatic kinetics 34, cancer detection 35, biochemistry 36, 37 and immunology 38, 39 amongst others.…”

Behavior of copper‐containing high‐entropy alloys in harsh metal‐dusting environments

“…[21,22] Mn is another element that is believed to strongly affect metal dusting, as-in contrast to Fe, Cu, Co, or Ni-it oxidizes in metal-dusting environments and, therefore, tends to promote unwanted spinel formation with Cr. [23] However, Mn-containing scales can prevent coking. [23] The alloying concept of high-entropy alloys (HEAs) has only recently started to be considered for extreme environments.…”

“…[23] However, Mn-containing scales can prevent coking. [23] The alloying concept of high-entropy alloys (HEAs) has only recently started to be considered for extreme environments. HEAs were introduced by Yeh and Cantor [24,25] in 2004, and ever since, many additional HEA systems have been reported.…”