Cryogenic electron tomography reveals the mesoporous structure evolution during γ-Al₂O₃ supported Mo and MoNiP...

Area of Science:

• Materials Science
• Catalysis
• Chemical Engineering

Background:

• Heterogeneous catalysts are crucial for industrial processes.
• Understanding support mesoporosity evolution during catalyst preparation is incomplete.
• Hydrodesulfurization (HDS) catalysts rely on specific support structures.

Purpose of the Study:

• To resolve the 3D mesopore structure of gamma-alumina (γ-Al₂O₃) supports.
• To assess structural changes induced by metal deposition (Mo, MoNiP) and sulfidation.
• To provide a 3D perspective on mesopore stability during HDS catalyst preparation.

Main Methods:

• Cryogenic electron tomography (cryo-ET) was employed to image the 3D mesopore structure.
• Analysis focused on γ-Al₂O₃ supports before and after Mo/MoNiP deposition and sulfidation.
• Image segmentation allowed separate analysis of the support and active MoS₂ phases.

Main Results:

• The intrinsic γ-Al₂O₃ mesopore structure showed high stability during calcination and sulfidation.
• Mo deposition slightly increased pore tortuosity and surface corrugation; MoNiP deposition had minimal impact.
• Sulfidation of both Mo and MoNiP catalysts led to more tortuous mesopores and corrugated surfaces.

Conclusions:

• Cryo-ET provides detailed 3D insights into mesopore stability during catalyst preparation.
• The γ-Al₂O₃ support structure is largely stable, with subtle modifications induced by processing.
• Advanced 3D imaging is essential for establishing robust structure-function correlations in catalysts.