Improvement of PROX-CO catalytical performance by modulation of the pore structure of CeO2 nanorods decorated with Au nanoparticles

Author(s)

Machado Silva, Raul Bruno ; de Oliveira, Cristine Santos ; Teixeira-Neto, Erico ; Sigoli, Fernando Aparecido ; Mazali, Italo Odone

• Document type: Journal article
• Source: Microporous and Mesoporous Materials; v. 330, p. 11-pg., 2022-01-06.

Abstract

Au/CeO2-based materials are widely investigated catalytical systems used for the preferential oxidation of CO (PROX-CO). Recent research focused on their improvement via the development and optimization of nanostructures, where both metal and oxide may be individually tailored to provide the best combination of catalytic performance, stability, and cost. In this work, we synthesized CeO2 porous nanorods using a facile hydrothermal synthesis and tailored their native porous structure using a simple acid lixiviation procedure to enlarge its pores and expose facets such as the {110} ones that are more susceptible to oxygen vacancy formation, one of the main requirements for PROX-CO. We decorated both lixiviated and as-synthesized CeO2 nanorods with Au nanoparticles using deposition-precipitation, and evaluated the effect of lixiviation over the morphology, structure, oxygen storage capacity and catalytic activity for PROX-CO. Through HRSTEM we observed an increase in the pore size while maintaining the morphology and structure of the nanorods. This increase was accompanied by the facilitation of oxygen vacancy formation, resulting in almost tripling the oxygen storage capacity (OSC). This impacted the performance of the CeO2/Au nanorods for PROX-CO, allowing a maximum of 88% CO conversion rate at 181 degrees C, compared to 27% and 238 degrees C for the non-lixiviated nanorods, under the same catalytical conditions. (AU)

• FAPESP's process: 16/21070-5 - Vibrational spectroscopy with spatial resolution
• Grantee: Mauro Carlos Costa Ribeiro
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 13/22127-2 - Development of novel materials strategic for integrated analytical devices
• Grantee: Lauro Tatsuo Kubota
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/07853-2 - Influence of the structural design of CeO2 porous nanorods decorated with bimetallic nanoparticles upon the optimization of water gas shift reaction
• Grantee: Raul Bruno Machado da Silva
• Support Opportunities: Scholarships in Brazil - Master