NdBaFe_2–xCo_xO_5+δ Double Perovskites with Exsolved Co–Fe Alloy Nanoparticles as Highly Efficient and Stable Anodes for Direct Hydrocarbon Solid Oxide Fuel Cells

Abstract

Exsolution of transition metals in perovskites is a potential way to improve the catalytic activity of fuel cell anode materials. In this work, the double-perovskite anodes PR-NdBaFe 2−x Co x O 5+δ (x = 0.1, 0.2; PR-NBFC10, PR-NBFC20) with the exsolved Co 0.72 Fe 0.28 metal alloy nanoparticles were obtained by heat treatment in 5% H 2 /Ar post-reduction at 850 °C. The exsolved Co−Fe alloy nanoparticle catalyst uniformly distributed on the surface of the cobalt-doped PR-NBFC10 and PR-NBFC20 ceramic anodes facilitates the catalytic activity compared with the undoped PR-NdBaFe 2−x Co x O 5+δ (x = 0; PR-NBFC0) anode. The maximum power density of single cells with PR-NBFC0, PR-NBFC10, and PR-NBFC20 anodes supported by a 200 μm thick La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3−δ electrolyte at 850 °C in wet H 2 reached 842, 1110, and 1247 mW cm −2 , respectively. In addition, PR-NBFC0, PR-NBFC10, and PR-NBFC20 exhibit relatively stable output power in a wet CH 4 fuel within 100 h of operation. Since the exsolved Co−Fe alloy nanoparticles have an embedded structure, they exhibit impressive anticoking properties, which greatly expand their application. The PR-NBFC double perovskite containing Co−Fe alloy nanoparticles offers possibilities for finding promising high-catalytic-activity and high-stability anodes for solid oxide fuel cells.

Exsolution on perovskite oxides: morphology and anchorage of nanoparticles

“…Nanoparticle exsolution on perovskite oxides has been a ''hot topic'' and focus of extensive research for more than a decade. Ni, 28,[31][32][33]38,39,41,45,47 Co, 80 Fe, 67,74 Ru, 90,93 Ag, [95][96][97] Au, 100 Fe-Ni, 35,[49][50][51][53][54][55][56][57][58][59]62,64 Co-Ni, 83 Co-Fe, 75,77,[79][80][81][82][83][84] Fe-Re, 49 (Pr,Ba)O x 103 Ellipsoidal 23 Ni, 29,30,32,40,46 Co, 87,88 Fe, 69,72,73 Ru,…”

“…Fe-Ni, 28,37,53,66,71,93 Ni, 33,45,63,64,97 Co-Fe, 51,59,83,100 Co, 45,60 Fe, 67,86 Bi-Fe, 52 Co-Ni, 82 Fe-Ru, 74 Ir 99 25% 8 Ni, 22,45 Co, 22 Co-Fe, 73 Fe, 36 Fe-Ni, 65 Fe-Ru, 74 Ir 99 33% 16 Co-Fe, 51,60,62,69,70 Fe-Ni, 32,46,72,85,94 Ni, 47,83 Co, 55 Co-Ni, 83 SrO 78 50% 33 Fe-Ni, 37,43,46,50,53,66,89,90,100 Ni,…”

Review on Fe-based double perovskite cathode materials for solid oxide fuel cells

“…To enhance the oxygen catalytic activity of LnBaFe 2 O 5 , surface modification methods, such as surface impregnation and in-situ precipitation, were experimented with and reported for LnBaFe 2 O 5 [17,[133][134][135][136] .…”

“…In addition, in-situ precipitation of nano metallic particles on the cathode surface has also been shown to increase the catalytic activity of the cathode [134,135] . Recently, in their study of Co-doped NdBaFe 2-x Co x O 5 (NBFCo x , x = 0.1,0.2), Jiang et al observed the in-situ precipitation of Co 0.72 Fe 0.28 nanoparticles when NBFCo x was reduced at 850 °C in 5%H 2 -Ar atmosphere [136] .…”