Solid-State Surface-Anchoring Strategy to Prepare Anti-Sintering Supported Metal Cluster Catalysts

Area of Science:

• Heterogeneous Catalysis
• Materials Science
• Nanotechnology

Background:

• Ultrasmall supported metal clusters (< 3 nm) are crucial in heterogeneous catalysis due to unique properties.
• High reaction temperatures cause particle coalescence, leading to loss of catalytic activity and stability.
• Developing thermally stable ultrasmall metal nanoclusters remains a significant challenge.

Purpose of the Study:

• To develop a solid-state synthesis strategy for thermally stabilized alumina-supported nickel (Ni) nanoclusters.
• To investigate the effect of Ni loading and calcination temperature on nanocluster dispersion and stability.
• To evaluate the catalytic performance and stability of the synthesized Ni nanoclusters in methane dry reforming.

Main Methods:

• Solid-state synthesis employing ball-milling processing for a 'surface-anchoring' strategy.
• Preparation of alumina-supported Ni nanoclusters with varying Ni loading (1 wt % and 5 wt %).
• Calcination at different temperatures (500 °C and 750 °C) to assess thermal stability.
• Characterization of Ni species dispersion and nanoparticle size.
• Evaluation of catalytic activity and stability in methane dry reforming reactions.

Main Results:

• Highly dispersed Ni species were observed at 1 wt % Ni loading even after 500 °C calcination, with no visible nanoparticles.
• At 5 wt % Ni loading and 750 °C calcination, significant Ni nanoparticles (approx. 6.8 nm) were formed but remained small.
• The 5-Ni-Al2O3-OAm-750 catalyst demonstrated excellent performance in methane dry reforming.
• The catalyst exhibited outstanding anti-coking properties during a 500-hour stability test.

Conclusions:

• The ball-milling based surface-anchoring strategy effectively synthesizes thermally stable Ni nanoclusters on Al2O3.
• The synthesized nanoclusters exhibit excellent catalytic activity and remarkable stability in methane dry reforming.
• This approach offers a promising route for developing robust catalysts for high-temperature applications.