Highly Cr-Substituted CeO2Nanoparticles Synthesized Using a Non-equilibrium Supercritical Hydrothermal Process: High Oxygen Storage Capacity Materials Designed for a Low-Temperature Bitumen Upgrading Process

Yuanzheng Zhu, Gimyeong Seong, Takio Noguchi, Akira Yoko, Takaaki Tomai, Seiichi Takami, Tadafumi Adschiri

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

As described herein, the synthesis of highly Cr-substituted CeO2 nanoparticles (Cr-CeO2) for low-temperature bitumen upgrading is demonstrated using a supercritical hydrothermal method including a subcritical region. A continuous flow reactor that can provide a non-equilibrium process was used to improve Cr substitution in the CeO2 lattice. Consequently, a Cr-substitution concentration of 22.7 mol %, which was unobtainable using the equilibrium process (5.1 mol %), was achieved. As the Cr-substitution concentration increased, the Cr-CeO2 morphology changed from a perfect octahedron to a cluster of small nanoparticles with high lattice strain. The increase in lattice strain strongly affects the rise in the oxygen storage capacity (OSC) of Cr-CeO2. Results show that high conversion of asphaltene (up to 47.9% at 350 °C) and high selectivity of syngas (H2 and CO, up to 58.3% at 350 °C) were achieved through low-temperature catalytic bitumen upgrading in the presence of highly Cr-substituted CeO2 nanoparticles. Furthermore, results show that the asphaltene conversion increased because of the rise in the OSC of Cr-CeO2, irrespective of the increase in the specific surface area, which indicates that the catalytic potential of Cr-CeO2 is more dependent on OSC than their specific surface area.

Original languageEnglish
Pages (from-to)4305-4319
Number of pages15
JournalACS Applied Energy Materials
Volume3
Issue number5
DOIs
Publication statusPublished - 2020 May 26

Keywords

  • OSC
  • asphaltene
  • coke
  • metal substitution
  • supercritical water

ASJC Scopus subject areas

  • Chemical Engineering (miscellaneous)
  • Energy Engineering and Power Technology
  • Electrochemistry
  • Materials Chemistry
  • Electrical and Electronic Engineering

Fingerprint Dive into the research topics of 'Highly Cr-Substituted CeO<sub>2</sub>Nanoparticles Synthesized Using a Non-equilibrium Supercritical Hydrothermal Process: High Oxygen Storage Capacity Materials Designed for a Low-Temperature Bitumen Upgrading Process'. Together they form a unique fingerprint.

Cite this