Ordered Mesopore Confined Pt Nanoclusters Enable Unusual Self-Enhancing Catalysis

Area of Science:

• Heterogeneous catalysis
• Materials science
• Sustainable chemistry

Background:

• Supported metal cluster (SMC) catalysts are crucial for sustainable processes but suffer from metal cluster aggregation and deactivation.
• Platinum nanoclusters (NCs) are highly active but prone to migration and sintering on catalyst supports.
• Developing stable and highly active SMC catalysts remains a significant challenge in chemical engineering.

Purpose of the Study:

• To synthesize and characterize stable platinum nanoclusters (NCs) confined within mesoporous titania (mpTiO₂).
• To investigate the catalytic performance and stability of Pt-mpTiO₂ in the water-gas shift (WGS) reaction.
• To elucidate the mechanism behind the observed self-enhancing catalytic activity.

Main Methods:

• Synthesis of mesoporous titania (mpTiO₂) with uniform spherical mesopores.
• Confinement of platinum nanoclusters (∼1.06 nm) within mpTiO₂ via interaction with anatase TiO₂ pore walls.
• Long-term testing of Pt-mpTiO₂ in the water-gas shift (WGS) reaction and selective hydrogenation of furfural.

Main Results:

• Pt-mpTiO₂ demonstrated excellent stability, retaining high CO conversion (∼95.0%) and stable Pt NC size (∼1.20 nm) during long-term WGS reaction.
• An unusual increasing catalytic activity was observed during cyclic WGS reactions.
• The enhanced activity was attributed to the *in situ* generation of interfacial active sites (Ti³⁺-O_v-Pt^δ+) via spillover hydrogen reduction.
• Superior performance was also noted in the selective hydrogenation of furfural to 2-methylfuran.

Conclusions:

• Stable Pt nanoclusters confined in mesoporous titania offer a robust catalyst for sustainable heterogeneous catalysis.
• The self-enhancing catalytic activity mechanism, driven by *in situ* generated interfacial sites, provides a new strategy for catalyst design.
• This work advances the development of stable and highly active supported metal cluster catalysts.