Spatially Aligned Binary Single-Site Catalyst on Defective SiO₂ for Cascading Reactions.

Area of Science:

• Heterogeneous catalysis
• Nanomaterials
• Catalyst design

Background:

• Single-atom catalysts (SACs) and dual-atom catalysts (DACs) are advancing heterogeneous catalysis.
• Uniformly distributed catalytic sites limit effectiveness in complex multistep cascading reactions.
• Precise spatial control of distinct single sites for sequential reactions remains a significant challenge.

Purpose of the Study:

• To develop a novel binary single-site catalyst with spatially aligned catalytic sites for cascade reactions.
• To investigate the synthesis and characterization of the Cu₁-Zr₁@SiO₂ catalyst.
• To evaluate the catalyst's performance in the ethanol conversion to butenes cascade reaction.

Main Methods:

• Synthesis of the Cu₁-Zr₁@SiO₂ catalyst using a modified reverse microemulsion approach.
• Characterization of the catalyst's surface and bulk structure using Low-Energy Ion Scattering Spectroscopy (LEIS).
• Testing the catalyst's performance in ethanol conversion, a model cascade reaction.

Main Results:

• The Cu₁-Zr₁@SiO₂ catalyst features spatially aligned Cu and Zr single sites, with Cu on the surface and Zr in the bulk.
• The catalyst successfully facilitated ethanol conversion to C₃+ olefins with a selectivity of 77.0% (56.0% butenes).
• The specific spatial arrangement suppressed ethylene formation and enhanced the desired product selectivity.

Conclusions:

• The developed binary single-site catalyst offers precise spatial control over catalytic active sites.
• This catalyst design is effective for intricate multistep cascading reactions like ethanol conversion.
• The study demonstrates a promising strategy for designing advanced catalysts for selective chemical transformations.