Synthesis, thermal stability, and oxygen intake/release characteristics of YBa(Co1−xAlx)4O7+δ

Abstract

The YBaCo 4 O 7+ (Y-114) phase has recently attracted interests as a potential oxygen storage material due to its oxygen intake/release capability at 200 ~ 400C.Nevertheless, thermal instability of Y-114 has been an obstacle for future applications, since this compound immediately starts to decompose when the sample is heated at 700 ~ 800C in oxygen-rich atmosphere. Here we demonstrate that Al-for-Co substitution in Y-114 drastically enhances the thermal stability. Substituting only 10 at% of aluminum for cobalt in Y-114 essentially suppresses the decomposition reaction seen at 700 ~ 800C, while well retaining its remarkable oxygen intake/release capability at 200 ~ 400C. It is also revealed that the addition of aluminum effectively reduces the particle size. The Al-substituted Y-114 products exhibit superior oxygen intake/release response to the Al-free products upon switching the atmosphere between O 2 and N 2 .

An oxygen pool from YBaCo4O7-based oxides for soot combustion

“…S4 †), probably due to the high heating rate in 5 vol% oxygen in He. 23 Furthermore, the XRD peaks of YBaCo 4 O 7+δ and YBaIJCo 0.85 Al 0.075 -Ga 0.075 ) 4 O 7+δ after TPO shift to higher angles, suggesting a lattice shrinkage, which confirms the participation of bulk oxygen.…”

High performance Pd–Rh/YBaCo4O7/γ-Al2O3 three-way catalysts for gasoil engine

“…Thus, it is obvious that the increasing of cerium amount reduces the particles size. Takafumi Komiyama et al interpreted this effect to mean that an addition of a certain amount of Al suppresses the grain growth of Y-114 [21]. The SEM images confirming that for YBa(Co 1−x Ce x )4O 7 samples only x = 0.1 make it thermal stable.…”

The YBaCo4O7+δ‐Based Functional Oxide Material Family: A Review

“…[56] In addition to iron, many other metal species have been investigated as possible substituents for cobalt: Mn, Ni, Cu, Zn, Al, Ga, and Li. [77,87] Zn, [25,[28][29][30]56,57,66,69,72,73,77,[88][89][90][91][92][93][94] Ga, [35,57,72,86,87,92,95] and Al [30,37,44,56,64,67,69,70,90,96,97] substitutions have been studied extensively owing to the stability they bring to the parent phase. [77,87] Zn, [25,[28][29][30]56,57,66,69,72,…”

“…[104] Partly replacing cobalt by other metal species reduces without exception the amount of oxygen the phase can reversibly absorb and desorb at low temperatures. [33,96] For zinc [30] and gallium, [35] the solubility limits are considerably higher; the amounts of these substituents needed in the YBa(Co,Zn/Ga) 4 O 7+δ structure to completely prevent the phase decomposition are 25 and 20 %, respectively. Part a of Figure 9 clearly shows the three metals that have the most beneficial impact on the decomposition, namely Al, Zn, and Ga.…”