TY - JOUR
T1 - Perovskite-type oxide ACo0.8Bi0.2O2.87 (A = La0.8Ba0.2)
T2 - A catalyst for low-temperature CO oxidation
AU - Dai, H. X.
AU - He, H.
AU - Li, W.
AU - Gao, Z. Z.
AU - Au, C. T.
N1 - Funding Information:
The work described in this paper was fully supported by a grant from the Hong Kong Baptist University (FRG/00-01/ I-15).
PY - 2001/5
Y1 - 2001/5
N2 - Perovskite-type oxide ACo0.8Bi0.2O2.87 (A = La0.8Ba0.2) has been investigated as a catalyst for the oxidation of carbon monoxide. X-ray diffraction results revealed that the catalyst is single-phase and cubic in structure. The results of chemical analysis indicated that in ACo0.8Bi0.2O2.87, bismuth is pentavalent whereas cobalt is trivalent as well as bivalent; in La0.8Ba0.2CoO2.94, cobalt ions exist as Co3+ and Co4+. The substitution of Bi for Co enhanced the catalytic activity of the perovskite-type oxide significantly. Over the Bi-incorporated catalyst, at equal space velocities and with the rise in CO/O2 molar ratio, the temperature for 100% CO conversion shifted to a higher range; at a typical space velocity of 30000 h-1 and a CO/O2 molar ratio of 0.67/1.00, 100% CO conversion was observed at 250°C. Over ACo0.8Bi0.2O2.87, at equal CO/O2 molar ratio, the temperature for 100% CO conversion decreased with a drop in space velocity; the lowest being 190°C at a space velocity of 5000 h-1. The result of O2-TPD study illustrated that the presence of Bi ions caused the lattice oxygen of La0.8Ba0.2CoO3-δ to desorb at a lower temperature. The results of TPR, 18O/16O isotopic exchange, and CO-pulsing investigations demonstrated that the lattice oxygen of the Bi-doped catalyst is highly mobile.
AB - Perovskite-type oxide ACo0.8Bi0.2O2.87 (A = La0.8Ba0.2) has been investigated as a catalyst for the oxidation of carbon monoxide. X-ray diffraction results revealed that the catalyst is single-phase and cubic in structure. The results of chemical analysis indicated that in ACo0.8Bi0.2O2.87, bismuth is pentavalent whereas cobalt is trivalent as well as bivalent; in La0.8Ba0.2CoO2.94, cobalt ions exist as Co3+ and Co4+. The substitution of Bi for Co enhanced the catalytic activity of the perovskite-type oxide significantly. Over the Bi-incorporated catalyst, at equal space velocities and with the rise in CO/O2 molar ratio, the temperature for 100% CO conversion shifted to a higher range; at a typical space velocity of 30000 h-1 and a CO/O2 molar ratio of 0.67/1.00, 100% CO conversion was observed at 250°C. Over ACo0.8Bi0.2O2.87, at equal CO/O2 molar ratio, the temperature for 100% CO conversion decreased with a drop in space velocity; the lowest being 190°C at a space velocity of 5000 h-1. The result of O2-TPD study illustrated that the presence of Bi ions caused the lattice oxygen of La0.8Ba0.2CoO3-δ to desorb at a lower temperature. The results of TPR, 18O/16O isotopic exchange, and CO-pulsing investigations demonstrated that the lattice oxygen of the Bi-doped catalyst is highly mobile.
KW - O/O isotopic exchange
KW - LaBaCoBiO
KW - Lattice oxygen mobility
KW - Low-temperature CO oxidation
KW - Oxidative nonstoichiometry
KW - Perovskite-type oxide catalyst
UR - http://www.scopus.com/inward/record.url?scp=0035353458&partnerID=8YFLogxK
U2 - 10.1023/A:1016622621897
DO - 10.1023/A:1016622621897
M3 - Journal article
AN - SCOPUS:0035353458
SN - 1011-372X
VL - 73
SP - 149
EP - 156
JO - Catalysis Letters
JF - Catalysis Letters
IS - 2-4
ER -