Effect of Ce and la dopants in Co 3 O 4 nanorods on the catalytic activity of CO and C 3 H 6 oxidation

Research output: Contribution to journalArticle

Researchers

  • Ping Li
  • Xiaoyin Chen
  • Lei Ma
  • Adarsh Bhat
  • Yongdan Li

  • Johannes W. Schwank

Research units

  • University of Michigan, Ann Arbor
  • Tianjin University
  • Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)

Abstract

Ce and La doped Co 3 O 4 nanorod catalysts were prepared and their catalytic activity for CO and C 3 H 6 oxidation reactions was examined. XRD, TEM, XPS, TPR, TGA and in situ DRIFTS have been used to characterize structural properties, reducibility, mobility of adsorbed oxygen and lattice oxygen, and surface intermediates for both CO and C 3 H 6 oxidation. When doping with either Ce or La, the cations occupy the Co 2+ sites in Co 3 O 4 . XPS, TPR, and TGA characterization showed that the Ce dopant decreased the ratio of surface adsorbed oxygen to lattice oxygen, and facilitated the extraction of adsorbed oxygen and lattice oxygen with hydrogen from CeO 2 -Co 3 O 4 in comparison to Co 3 O 4 , while the La dopant caused the opposite effect. The light-off performance for both CO and C 3 H 6 oxidations has been improved due to Ce doping on Co 3 O 4 , while the doping of La actually inhibited the oxidation activity of the Co 3 O 4 catalyst. Similar catalytic activity facilitation and inhibition of Ce and La dopants were also observed for the simultaneous oxidation of CO, C 3 H 6 , and NO under the conditions of simulated diesel exhaust. The results of in situ DRIFTS suggested that bidentate carbonate species could be the key intermediates of CO oxidation, which would further react with CO to form CO 2 . The results of DRIFTS showed that the mobility of lattice oxygen plays an important role in the C 3 H 6 oxidation. A mechanism was proposed where the formate and acetate species could be the reaction intermediates of C 3 H 6 oxidation, and these intermediates are more stable on La 2 O 3 -Co 3 O 4 than on Co 3 O 4 and CeO 2 -Co 3 O 4 catalysts.

Details

Original languageEnglish
Pages (from-to)1165-1177
Number of pages13
JournalCATALYSIS SCIENCE AND TECHNOLOGY
Volume9
Issue number5
Publication statusPublished - 7 Mar 2019
MoE publication typeA1 Journal article-refereed

    Research areas

  • LOW-TEMPERATURE OXIDATION, PROPANE OXIDATION, COBALT OXIDE, PROPENE OXIDATION, SURFACE, PERFORMANCE, DIESEL, EMISSIONS, EFFICIENT, TOLUENE

ID: 32558226