Pt Molecularly Defined Precursors to Tune Particle Size and Speciation: Impact on the Reverse Water Gas Shift Reaction

Author(s)

Sousa, Leonardo da Silva ; Strapasson, Guilherme Boenny ; Bueno, Jose Maria Correa ; Oliveira, Caio Costa ; Zanchet, Daniela

• Document type: Journal article
• Source: CHEMISTRY OF MATERIALS; v. 36, n. 9, p. 13-pg., 2024-04-18.

Abstract

Platinum-based catalysts have been largely explored for CO2 valorization by the reverse water gas shift (RWGS) reaction, especially the Pt/TiO2 system. Understanding the distinct roles of various Pt species and the metal-support interaction, as well as finding ways to tailor them, is crucial for developing and optimizing more active systems. Herein, we employed molecularly defined Pt2+ precursors based on salen ligand for easy Pt speciation according to the activation protocol. Salen-derived ligands are easily accessible coordination compounds that can be designed and combined with various metals, serving as versatile alternatives to create a broad library of metallic precursors. Pyrolysis, oxidizing, or reducing thermal pretreatments were used to decompose the coordination complexes impregnated on TiO2, impacting the Pt species formed, their local environment, electronic properties, and interaction with the support. We showed that at low temperatures (below 300 degrees C), metallic Pt nanoparticles had the highest activities; however, once exposed to harsher reactional conditions (>400 degrees C), they deactivated. On the other hand, an oxidative pretreatment induced the growth of mobile platinum clusters that, under a harsher reducing RWGS reactional atmosphere, redispersed into single atoms, being the dominant active site and presenting high activity and stability. (AU)

• FAPESP's process: 18/01258-5 - Novel chemical catalytic and photocatalytic processes for the direct conversion of methane and CO2 to products
• Grantee: José Maria Correa Bueno
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/01669-5 - New quiral metal catalysts and their applications in asymmetric catalysis
• Grantee: Caio Costa Oliveira
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 20/12986-1 - Design of nickel catalysts supported on 1D TiO2/Nb2O5 nanostructures
• Grantee: Guilherme Boenny Strapasson
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 20/08575-6 - Electronic modulation of Pt atomically dispersed on oxides aiming catalytic applications
• Grantee: Leonardo da Silva Sousa
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)