Unraveling the Nuclearity Effect of Atomically Choreographed Triatom Cu₃ Clusters Supported on Zeolites

A precise understanding of the structure-activity relationship of catalysts is crucial for catalysis research and is essential for rationalizing next-generation catalysts. As the size of catalysts decreases from nanometric to atomic dimensions, the focus on structure-activity relationship correlation has shifted from the "size effect" to the much more challenging "metal nuclearity effect". However, precise synthesis and reliable characterization for structurally related solid atomic catalysts, such as single-, dual-, and triatom catalysts, still remain extremely challenging. Here, we present the controlled assembly of single-atomic Cu₁, dual-atomic Cu₂, and triatomic Cu₃ supported on zeolites through an innovative atomically choreographed approach. For the first time, we have directly visualized the atomic features of Cu₃ with respect to the zeolitic channels using double aberration-corrected scanning transmission electron microscopy (STEM). The structural and electronic properties of the catalysts have been characterized using synchrotron X-ray absorption spectroscopy, high-resolution synchrotron powder X-ray diffraction (PXRD), and density functional theory (DFT) calculations. We revealed the interplay among surface structures, adsorption configurations, catalytic reactivities (showing a significant 25-fold improvement), and product selectivity across structurally related species using a model methanol reforming reaction. We have successfully elucidated the relationship between the metal nuclearity effect and its activity and selectivity in a complex catalytic reaction. Our findings offer an unprecedented opportunity for the catalysis and materials community to finely manipulate the physicochemical properties of this category of solid atomic catalysts to achieve the desired reactivities and selectivities.