Nickel Nanocatalyst Ex-Solution from Ceria-Nickel Oxide Solid Solution for Low Temperature CO Oxidation

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Ceria (CeO2) based materials are crucial for catalytic applications.
• Improving catalytic activity and stability of ceria supports is an ongoing research area.
• Carbon monoxide (CO) oxidation is a key reaction in various industrial processes.

Purpose of the Study:

• To develop highly active and stable nanocatalysts for low-temperature CO oxidation.
• To investigate the in situ growth of Ni nanocatalysts on CeO2 via Ni ex-solution.
• To understand the role of Ni ex-solution on CeO2 surface for catalytic performance.

Main Methods:

• Preparation of NiO-CeO2 solid solutions using the solution combustion method.
• In situ reduction of NiO-CeO2 at 1000 °C in a 5% H2/Ar atmosphere to induce Ni ex-solution.
• Characterization using X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM).
• Evaluation of catalytic activity and stability for CO oxidation reaction.

Main Results:

• NiO-CeO2 doping with Ni increases oxygen vacancies.
• Successful ex-solution of 9.2 nm Ni nanoparticles onto the CeO2 surface.
• The Ni-exsolved sample (R-UCe5Ni10) exhibits significantly enhanced catalytic activity (T50 ~ 110 °C) and stability (100 h) for CO oxidation.
• Lower apparent activation energy (48.4 kJ mol-1) for the Ni-exsolved sample.

Conclusions:

• In situ ex-solution of Ni nanocatalysts onto CeO2 is an effective strategy to boost catalytic performance.
• The strong adherence of ex-solved Ni nanoparticles to the CeO2 support enhances CO oxidation.
• The developed Ni-exsolved CeO2 catalyst shows practical applicability for CO oxidation reactions.