(691e) Atom-By-Atom Active Site Synthesis By Liquid-Phase Atomic Layer Deposition

Understanding and engineering the active sites of heterogeneous catalysts is often elusive due to the high structural complexity of the surfaces involved and the co-existence of different sites. However, a better understanding and control of active sites’ atomic configuration could facilitate the optimization and even rational design of heterogeneous catalysts down at the atomic level. The study of single-atom catalysts represents a promising way to assess individual properties of elements. However, the activity of a given site is often controlled as much by the active atom than by its surroundings, and the latter is still challenging to control [1].

Here, we will present a heterogeneous catalyst preparation method that goes beyond single-atom catalyst synthesis by providing additional control over the composition and the structure of the surrounding catalytic site [2]. Our approach based on liquid-phase atomic layer deposition [3], provides an atomic control over the atomic cluster surrounding the active atom by building coordination spheres shell by shell. As a proof of concept, a series of multi-nuclear catalytic clusters were prepared using aluminum, zinc, silicon and magnesium precursors on a high surface area dehydroxylated silica. Catalytic non-oxidative propane dehydrogenation was used as model reaction to probe the influence of the atomic composition and structure surrounding a single site zinc catalyst. Extensive spectroscopy (X-ray absorption, solid state NMR, XPS, STEM-EDX) analysis were performed in order to confirm the targeted structures and better understand the role atomic surroundings on the properties of the single site.

[1] F. Calle-Vallejo et al, Science, 2015, 350, 6257

[2] B. P. Le Monnier et al, in preparation

[3] B. P. Le Monnier et al, Adv. Mater. 2019, 31, 1904276