William Tiznado

TITLE:

From Stable Clusters to Functional Nanomaterials: Building Blocks for Hydrogen Storage and Single-Atom Catalysis

ABSTRACT:

Clusters, aggregates of atoms that bridge the molecular and solid-state domains, often display unexpected stability patterns that cannot be extrapolated directly from bulk chemistry. This anomalous stability arises from principles such as electronic shell closures, multicenter bonding, and aromatic delocalization, which provide predictive rules for identifying favored configurations. When clusters exhibit such collective electronic states, they can be regarded as superatoms—element-like entities that mimic atomic behavior and serve as atomically
precise building blocks. This concept has led to the development of cluster-assembled materials, a bottom-up strategy to construct solids with tailored properties for energy storage, electronic devices, and catalysis.
This contribution presents recent computational work in which aromaticity and electron-counting rules are applied to design clusters with potential as functional building units. The Li₇Si₅⁺ cluster, which reproduces the electronic structure of the aromatic cyclobutadienyl anion, emerges as a fundamental motif and notably appears as a structural component in the Li₁₂Si₇ Zintl phase. Similarly, the Li₆Si₅ cluster, consisting of a pentagonal Si₅⁶⁻core stabilized by Li⁺ counterions, resists oligomerization, highlighting its persistence as a robust module for
constructing nanowires and extended Li–Si frameworks. Beyond silicon-based clusters, the B₃₆ boron cluster provides a distinctive platform: its central hexagonal vacancy accommodates transition metals, giving rise to M@B₃₆ complexes (M = transition metals) that function as prototypical single-atom catalyst models. First- principles simulations confirm the stability of these doped clusters both in the isolated state and when supported on graphene substrates.
Overall, this work illustrates how bonding concepts and aromatic stabilization provide a rational framework to explain anomalous cluster stability and to translate it into functional designs. These insights demonstrate the potential of clusters to evolve into practical building blocks for hydrogen storage, one-dimensional nanowires, and single-atom catalytic systems, advancing the design of next-generation nanomaterials.

BIO:

William Tiznado Vásquez is a Full Professor in the Department of Chemical Sciences, Faculty of Exact Sciences, Universidad Andrés Bello (Chile), where he also serves as Director of the Center for Research in Materials Design (CEDEM). He earned his Licenciatura in Chemistry from the Universidad Nacional Federico Villarreal (Peru) and his Ph.D. in Chemistry from the Universidad de Chile, followed by postdoctoral research at the Universidad de Chile and Pontificia Universidad Católica de Chile.
His research focuses on theoretical and computational chemistry, with emphasis on aromaticity, chemical bonding, cluster design, and nanomaterials. He has made important contributions to the understanding of planar hypercoordinate species, silicon–lithium nanoclusters, and boron-based clusters, connecting fundamental bonding concepts with applications in hydrogen storage and single-atom catalysis.
Professor Tiznado has published extensively in leading journals such as Angewandte Chemie, Journal of the American Chemical Society, Chemistry – A European Journal, and Chemical Science. He has supervised numerous graduate students, fostering the next generation of computational chemists, and actively promotes interdisciplinary collaborations that integrate computational strategies with experimental innovation to address challenges in energy, catalysis, and functional materials.