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As the energy crisis and environmental pollution continue to intensify, the demand for clean energy has increased. Using two-dimensional materials to catalyze overall water splitting is an important pathway for clean energy production. This study investigated the catalytic hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) of tri-atomic clusters supported on a two-dimensional material, graphenylene (GPN). The structural stability of GPN was thoroughly investigated, and materials were employed as substrates to support a series of 28 distinct trimer clusters composed of 3d, 4d, and 5d transition metals. Ideal combinations of these systems were screened and designed. The loading configurations of TM3@GPN in two different systems were systematically studied. The stability of the catalyst was assessed by calculating the binding and cohesive energies and by performing molecular dynamics simulations, to confirm the catalyst stability. The optimal bifunctional catalysts for overall water splitting were identified as Au3@GPN, Pt3@GPN, and Pd3@GPN, all of which demonstrated superior overall water splitting performance. As a novel two-dimensional material, biphenylene-based materials, when used to support metal clusters as bifunctional catalysts for water splitting, represent an efficient and innovative approach.

Atomic clusters are the bridge between molecules and the bulk matter. Following two key experiments — the observation of electronic shells in metallic clusters and the discovery of the C60 fullerence — the field of atomic clusters has experienced a rapid growth, and is now considered a mature field. The electrons of the cluster are confined to a small volume, hence, quantum effects are manifested on many properties of the clusters. Another interesting feature is that the properties often change in a non-smooth way as the number of atoms in the cluster increases. This book provides an updated overview of the field, and presents a detailed description of the structure and electronic properties of different types of clusters: Van der Waals clusters, metallic clusters, clusters of ionic materials and network clusters. The assembling of clusters is also considered, since specially stable clusters are expected to play a role in the future design and synthesis of new materials.

Machine learning interatomic potentials (MLIPs) enable accurate atomistic modeling, but reliable uncertainty quantification (UQ) remains elusive. In this study, we investigate two UQ strategies, ensemble learning and D-optimality, within the atomic cluster expansion framework. It is revealed that higher model accuracy strengthens the correlation between predicted uncertainties and actual errors and improves novelty detection, with D-optimality yielding more conservative estimates. Both methods deliver well calibrated uncertainties on homogeneous training sets, yet they underpredict errors and exhibit reduced novelty sensitivity on heterogeneous datasets. To address this limitation, we introduce clustering enhanced local D-optimality, which partitions configuration space into clusters during training and applies D-optimality within each cluster. This approach substantially improves the detection of novel atomic environments in heterogeneous datasets. Our findings clarify the roles of model fidelity and data heterogeneity in UQ performance and provide a practical route to robust active learning and adaptive sampling strategies for MLIP development.

The rapidly emerging field of atomic cluster collisions attracts strong research interest of many experimental and theoretical groups worldwide. Being a highly interdisciplinary field, it has numerous links with atomic, molecular and optical physics, astrophysics, plasma physics, biophysics, physical chemistry, solid state physics and even molecular biology. This Topical Issue presents a state-of-the-art description of current research activities in the field of atomic cluster collisions and atomic cluster science. The contributions to this Issue represent experimental, theoretical and computational studies both at the fundamental level of elementary mechanisms and at a more applied level which is necessary in numerous applications of nano- and biotechnology, materials science and medicine.

The previously described cyclic pathway method for deposition of atomic metals has been used to create Pd 1–6 atomic clusters and Au 1–5 Pd 1 and Au 1–4 Pd 2 bimetallic atomic clusters in polyaniline (PANI). The controlled deposition of predetermined atomic size clusters of metals has been examined by testing the electrochemical oxidation of n -propanol in 1 M NaOH. The oxidation peak currents from the cyclic voltammograms were found to follow the same trend as the changes of the calculated HOMO–LUMO gap energies. The FTIR signature of PANI for these films also followed the calculated trend. This study also looks at the effects of atomic arrangement in the atomic structure on the support matrix of PANI. The results presented here have shown that the cyclic pathway is a versatile method for the atomic deposition of single metal, bimetallic, or even trimetallic atomic clusters in PANI. Graphical Abstract

Preparing stable highly dispersed Pt based electrocatalyst is promising to reduce material expense of H2 product via electrocatalytic water splitting. However, it is still a great challenge to obtain stable single atomic Pt catalysts which can be applied in acidic electrolyte. In the present work, we synthesized Pt atomic clusters on carbon quantum dots (CQDs) grafting multiwall carbon nanotube (CNT) (Pt content: 1 wt.%) catalysts and then loading the catalysts on carbon cloth (Pt content: 0.01 mg▪cm–2) for activity test. The overpotential of 29 mV versus RHE was obtained over 1%Pt/CQDs/CNT catalysts at the current density of 10 mA▪cm–2, and the Tafel slope of 22 mV decade–1 was obtained, too. Especially, the catalysts showed significant stability in hydrogen evolution reactions (HER) in acidic solution, of which the overpotential was still smaller than that of 20%Pt/C after 10,000 CV cycles. CQDs provided coordinating sites for dispersing Pt atomic clusters and improved the H+ concentration in adjacent area around the Pt clusters. This method provides a general strategy to design the highly efficient electrocatalysts with ultra‐low precious metals for H2 evolution in acidic electrolyte.

The performance optimization of isolated atomically dispersed metal active sites is critical but challenging. Here, TiO₂@Fe species-N-C catalysts with Fe atomic clusters (ACs) and satellite Fe-N₄ active sites were fabricated to initiate peroxymonosulfate (PMS) oxidation reaction. The AC-induced charge redistribution of single atoms (SAs) was verified, thus strengthening the interaction between SAs and PMS. In detail, the incorporation of ACs optimized the HSO₅⁻oxidation and SO₅ ·− desorption steps, accelerating the reaction progress. As a result, the Vis/TiFeAS/PMS system rapidly eliminated 90.81% of 45 mg/L tetracycline (TC) in 10 min. The reaction process characterization suggested that PMS as an electron donor would transfer electron to Fe species in TiFeAS, generating ¹O₂. Subsequently, the hVB⁺ can induce the generation of electron-deficient Fe species, promoting the reaction circulation. This work provides a strategy to construct catalysts with multiple atom assembly–enabled composite active sites for high-efficiency PMS-based advanced oxidation processes (AOPs).

The ISACC 2015 brought together nearly a hundred scientists in the field of atomic and molecular cluster physics from around the world. We deliver the Editorial of a topical issue compiling/presenting original research results from some of the participants on both experimental and theoretical studies involving research areas from small clusters to extended molecular systems in the field.

Tungsten carbides, featured by their Pt-like electronic structure, have long been advocated as potential replacements for the benchmark Pt-group catalysts in hydrogen evolution reaction. However, tungsten-carbide catalysts usually exhibit poor alkaline HER performance because of the sluggish hydrogen desorption behavior and possible corrosion problem of tungsten atoms by the produced hydroxyl intermediates. Herein, we report the synthesis of tungsten atomic clusters anchored on P-doped carbon materials via a thermal-migration strategy using tungsten single atoms as the parent material, which is evidenced to have the most favorable Pt-like electronic structure by in-situ variable-temperature near ambient pressure X-ray photoelectron spectroscopy measurements. Accordingly, tungsten atomic clusters show markedly enhanced alkaline HER activity with an ultralow overpotential of 53 mV at 10 mA/cm 2 and a Tafel slope as low as 38 mV/dec. These findings may provide a feasible route towards the rational design of atomic-cluster catalysts with high alkaline hydrogen evolution activity. While platinum is a highly active catalyst for H 2 evolution, its low abundance prompts research into earth-abundant alternatives. Here, authors prepare tungsten atomic clusters on phosphorus doped carbon by thermal migration and demonstrate excellent activities for hydrogen evolution electrocatalysis.

AbstractInfrared spectra are computed for neutral and cationic clusters of Polycyclic Aromatic Hydrocarbon molecules, namely (C16H10)n=1,4(0/+) , using the Density Functional based Tight Binding scheme combined with a Configuration Interaction (DFTB-CI) in the double harmonic approximation. Cross-comparison is carried out with DFT and simple DFTB. Similarly to the monomer cation, the IR spectra of cluster cations are characterized by a depletion of the intensity of the CH stretch modes around 3000 cm−1, with a weak revival for n = 3 and 4. The in-plane CCC modes in the region 1400–2000 cm−1 are enhanced while the CH bending modes in the range 700–1000 cm−1 are significantly weakened with respect to the monomer cation, in particular for n = 2. Finally, soft modes corresponding to diedral fluctuations of the monomers within the central stack of the ion structure, possibly mixed with monomer folding, are also observed in the region 70–120 cm−1.Graphical abstract