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Hydrogen evolution reaction (HER) is a promising route for sustainable hydrogen production. However, its efficiency is limited by kinetic barriers. Herein, we employ density functional theory (DFT) calculations to demonstrate a new strategy of embedding tetrametallic transition metal clusters (3TM 1 -TM 2) into the pores of graphdiyne (GDY) to effectively optimize its HER performance. By screening 900 configurations, 10 prototypes displayed near-ideal hydrogen adsorption free energies. Among them, 3W–Hg@GDY with a ΔG H of −0.00035 eV was identified as the optimal candidate. Analysis of the electronic structure reveals hybridization between the metal d orbitals and GDY p orbitals near the Fermi level, creating partially filled impurity states to promote hydrogen adsorption. Additionally, coordination between the three TM 1 atoms and active TM 2 atom in the cluster enables precise tuning of TM 2 's electron density to achieve a moderate interaction with the adsorbed H, facilitating superior HER catalysis. Our findings showcase a new paradigm of cluster engineering for modulating GDY's reactivity that holds great promise as a universal approach for the design of high-performance GDY-based electrocatalysts beyond HER. Through screening 900 configurations of tetrametallic transition metal clusters embedded in graphdiyne via DFT calculations, we identified 10 prototypes displayed near-ideal hydrogen adsorption free energies. [Display omitted] • Screened 900 GDY-cluster configs; 10 show near-ideal HER adsorption energies. • 3 W–Hg@GDY: ΔG H -0.00035 eV, closest to ideal among prototypes. • Metal d-orbitals, GDY p-orbitals hybridization aids H adsorption. • Precisely tuned electron density on active site via coordination with three atoms enables optimal binding. [ABSTRACT FROM AUTHOR]

This article investigates the structural stability and hydrogen adsorption performance of Na-decorated heteroborospherene Si 4 B 32 using density functional theory (DFT) methods. DFT calculations demonstrate that six sodium (Na) atoms can successfully and chemically bind to the surface of heteroborospherene Si 4 B 32 , exhibiting a substantial average binding energy of 2.465 eV without clustering. Moreover, the resulting Na 6 Si 4 B 32 structure retains its integrity even after absorbing up to 30 hydrogen (H 2) molecules, with an average adsorption energy of 0.251 eV/H 2. Utilizing DFT analysis, the gravimetric density of Na 6 Si 4 B 32 ·(H 2) 30 can reach 9.143 wt%. Additionally, employing ab initio molecular dynamics (AIMD) simulations, we find that a significant fraction of the H 2 molecules desorb from Na 6 Si 4 B 32 at 300K within 1000 fs. These findings establish the potential of Na-decorated heteroborospherene Si 4 B 32 as a promising candidate for reversible hydrogen storage. The successful binding of Na atoms without clustering and the substantial H 2 adsorption capacity, coupled with the structural stability and facile H 2 desorption observed at moderate temperatures, highlight the viability of this material for practical hydrogen storage applications. [Display omitted] • The Na atoms can bind on the surface of Si 4 B 32 without metal clustering. • The Na 6 Si 4 B 32 cluster can adsorb up to 30H 2 molecules with a hydrogen storage capacity of 9.143 wt%. • H 2 adsorption energy locates in the range from 0.251 to 0.320 eV/H 2. • Dynamics simulation results verify the reversibility of H 2 storage. [ABSTRACT FROM AUTHOR]

In this work, the hydrogen storage capability in light metal (Na and K) decorated heteroborospherene C4B32 was investigated by using density functional theory (DFT) calculations. Na atoms can strongly bind to C4B32 with the average binding energy of 2.720 eV. The clusters of Na atoms decorated C4B32 are observed to be structurally stable even after the adsorption of H2 molecules. Each Na atom can adsorb 6H2 molecules with average adsorption energy of 0.199 eV/H2 yielding gravimetric H2 uptake of 8.99 wt%. However, the average adsorption energy of H2 molecules in K4C4B32 is much less than 0.2 eV. Therefore, Na decorated heteroborospherene C4B32 can act as an effective material for reversible H2 storage. • Na and K atoms bind strongly on C 4 B 32 and do not agglomerate together. • K decorated C 4 B 32 is not suitable for H 2 storage due to unqualified adsorption energy. • Na 4 C 4 B 32 stores 24H 2 molecules with average adsorption energy of 0.199 eV/H 2. • The desorption temperature of Na 4 C 4 B 32 ·(H 2) 24 is 289 K. [ABSTRACT FROM AUTHOR]

The induced impacts of high doses of gamma irradiations on the optical features of the Makrofol DE 1-1 detector were studied in the ultraviolet and visible range (from 270 to 500 nm). Makrofol DE 1-1 detector specimens were irradiated separately for different doses from 200 to 1000 kGy; step 200. The optical absorbance spectra of the pristine Makrofol DE 1-1, as well as the irradiated gamma-ray samples display two main features: (i) A redshift with further gamma-ray irradiation doses from 200 to 1000 kGy. This redshift can be ascribed to irradiation-induced defects in polymer material. (ii) A remarkable increment in the optical absorbance for irradiated Makrofol DE 1-1 specimens compared to the pristine one. This increment can be ascribed to the creation of some electronic levels within the forbidden gap resulting from the irradiation process. Moreover, this absorbance increment was employed to assess the degradation percent produced by gamma-ray irradiations. The degradation percent of the Makrofol DE 1-1 increased from 31.73% at 200 kGy to 78.08% at 1000 kGy. The optical band gap, Fermi level and metallization criterion showed decrement behaviors with further doses of gamma-ray irradiations. Also, the percent of changes in optical band gap values were employed to evaluate the degradation of Makrofol DE 1-1 under gamma-ray irradiations. This percent augmented from 15.19% at 200 kGy to 20.25% at 1000 kGy proving the obvious degradation of Makrofol DE 1-1 under gamma-ray irradiations. On the other hand, the number of carbon atoms per cluster, linear and nonlinear refractive indices showed increasing behaviors with further doses of gamma-ray irradiations. [ABSTRACT FROM AUTHOR]

Semiconductor materials anchored with transition metal cluster are promising photocatalysts for photocatalytic hydrogen evolution. In this paper, Co, N-co-doped graphene modified thin mesoporous carbon nitride (Co-NG/TMCN) was be synthesized through electrostatic adsorption treatment. Extensive characterization was used to explore the morphology, structures and optical properties of the as-prepared photocatalysts. The 10 wt% Co-NG/TMCN exhibited the high photocatalytic hydrogen evolution rate (2949 μmol g−1) within 4 h visible light irradiation, which was about 113 times than that of the pure TMCN (26 μmol g−1). Co-NG material with excellent electrical conductivity played a major role in accelerating charge transfer from TMCN material to cobalt atomic clusters. The photocatalytic hydrogen evolution performance of Co-NG/TMCN material was effectively improved. Consequently, a feasible approach for doping transition metal clusters to enhance photocatalytic activity was provided. • The introduction of cobalt atomic clusters provided more active sites. • The synergy between Co, N-co-doped graphene and thin mesoporous carbon nitride was beneficial to the ficient separation of photogenerated electrons. • The low content cobalt atomic clusters were efficiently utilized to increase hydrogen production rate. [ABSTRACT FROM AUTHOR]

Alkaline water electrolysis is a safe and efficient method for producing hydrogen that is favored by the industry. At present, single-atom catalysts have attracted extensive attention due to their extremely high atom utilization. However, studies on the single-atom site catalytic mechanism of the Volmer step, the rate-determining step of the cathodic HER reaction, are lacking. Here, we used ZIF-8 to obtain double-layer N-doped porous carbon nanocages, and successfully achieved the co-loading of Pt single atoms and their clusters (NPCN–Pt). The turnover frequency (TOF) and mass activity of NPCN–Pt are 5 and 7.2 times higher than those of commercial Pt/C, respectively, and the former exhibits significantly better stability than Pt/C. Theoretical calculations show that Pt clusters have a lower activation energy barrier for water molecules compared to Pt single atoms, which favors the Volmer step. The ΔG H* of Pt single-atom sites is smaller than that of Pt clusters, which is more conducive to the release of H 2. The study shows that Pt clusters and single atoms can synergistically catalyze the HER reaction, providing new ideas for the development of efficient HER catalysts. Double-layer N-doped carbon nanocages were obtained by ZIF-8, and Pt single atoms and clusters were simultaneously loaded for alkaline HER catalysis. The synergistic catalysis of single atoms and clusters enables its TOF and mass activity to be 5 times and 7.2 times higher than that of commercial Pt/C, respectively. [Display omitted] • MOFs-derived bilayer N-doped porous carbon nanocages for co-loading of Pt single atoms and clusters. • The turnover frequency (TOF) and mass activity of NPCN–Pt are 5 and 7.2 times higher than those of Pt/C, respectively. • Pt single atoms and clusters have a synergistic effect on catalyzing alkaline HER. [ABSTRACT FROM AUTHOR]

The cluster-knockout reaction project, ONOKORO, has been launched to elucidate the formation mechanism of clusters in atomic nuclei. For the inverse-kinetics cluster-knockout reaction experiments, a new detector array is under development to measure energies and angles of light ions emitted in the reactions. The silicon tracker tracks the particles with good angular and energy-loss resolutions. A performance test of the silicon strip detectors with a thickness of 100 μ m and a strip width of 100 μ m was performed using prototype silicon detectors. The mono-energetic proton and α -particle beams were irradiated on the silicon detectors. The energy-loss spectra in silicon detectors showed a good signal-to-noise ratio. The threshold level for signal detection is seven sigma of noise level. Their dynamic ranges were optimized wide enough to detect charge number Z = 1 and Z = 2 ions emitted in the cluster-knockout reactions. [ABSTRACT FROM AUTHOR]

We have launched a new research project named "ONOKORO" to elucidate the formation mechanism of clusters in atomic nuclei. The project comprehensively investigates clustering phenomena in the medium-to-heavy mass region with inverse-kinematics cluster-knockout reactions at the intermediate energy facilities. The new detector array named "TOGAXSI" is under construction for this purpose. It measures scattering angles and the energies of deuterons, tritons, 3 He, and α particles emitted at forward angles from the cluster-knockout reactions. It also measures the recoil protons emitted from the scattering events at large angles. High-angular and high-energy resolutions with wide solid angles are required to achieve a good cluster separation energy resolution and a reasonably high yield. The designed telescope consists of silicon trackers and GAGG:Ce calorimeters. This paper shows the required conditions and design concepts of TOGAXSI. [ABSTRACT FROM AUTHOR]

Within PRISMAP, the European medical radionuclides program, we are investigating the possible enrichment of titanium and calcium stable isotopes by means of Separation of Isotopes by Laser Assisted Retardation of Condensation (SILARC). Titanium or calcium-containing molecules are injected in a gas cell containing argon as a buffer gas and released via a nozzle creating a supersonic jet. The temperature drops to ∼ 15 K, at which point argon atoms cluster around the molecules. If an isotopomer can be selectively excited by an infrared laser, the clusterization can be prevented and the molecule experiences a drag force through the jet, physically separating it from the clusters. As a first step in this development, Density Functional Theory (DFT) calculations have been performed on titanium-containing molecules, to determine the ground-state configuration of the molecules (geometry and spin state), their interaction with Ar, and to calculate the frequencies of their vibrational modes as a function of Ti isotope. Isotope-selective transitions were identified, mostly in the mid-infrared region. In this contribution, the results from those calculations for simple molecules (Ti F x (x = 1 − 4)) and complex molecules (Ti[OEt] 4 , Ti[OPr] 4 , C 10 H 2 TiF 12 O 4) are reported. [ABSTRACT FROM AUTHOR]

[Display omitted] • Constructing N-doped carbon supported Co catalyst for lignin-first strategy. • Catalyst morphology, metal dispersion and N content were regulated by melamine dosage. • Pyridinic N enhanced lignin adsorption and decreased C–O bond disassociation energy. • Atom-cluster Co was loaded by the presence of pyridinic N in the carrier. • 40.62 wt% of monophenolics from lignin and 84.02 wt% of cellulose were obtained. The lignin-first strategy is a crucial approach for highly efficient depolymerization of lignin to produce aromatic monomers as the condensation of lignin occurred during the separating process which increased the difficulty in depolymerization. In this work, a cobalt atom clusters supported on nitrogen-doped carbon catalysts (Co/NC-15) was prepared by adjusting the dosage of melamine to control the morphology, structure, and pyridinic nitrogen content of the catalysts. DFT calculations based on lignin model showed that the doping of nitrogen increased the adsorption energy of the lignin on the supports and decreased the dissociation energy of C-O bonds. Under lignin first strategy, Co/NC-15 exhibited good ability to break C-O bonds at 220 °C of mild condition, in which 84.32 wt% of lignin in lignocellulosic biomass was converted into 40.62 wt% of aromatic monomers, while 84.02 wt% of cellulose was preserved. The atom clusters Co/NC-15 exhibited good catalytic activity to lignin depolymerization due to efficient cleavage of C-O bonds, and hence showed the promising prospect in potential industrial application. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni/P atomic clusters were decorated onto the surface of Co nanoparticles. • Atomic clusters serve as reaction switch to regulate the reaction pathway. • Hydrogen production system coupling with glycerol oxidation was built. In this work, Ni/P clusters have been successfully decorated onto the surface of Co nanoparticles. The surface decoration with Ni/P clusters greatly enhance the electron interaction in the catalytic system. The optimized catalyst exhibits a high activity for electrocatalytic glycerol oxidation coupling with alkaline hydrogen evolution reaction. A hydrogen-producing electrolysis cell with formate faradaic efficiency of 64.5 % has been assembled, which can achieve a decomposition voltage as low as 1.37 V at a current density of 10 mA cm−2. More importantly Ni/P clusters not only serve as real active sites, but also as reaction switches to regulate the progress of oxygen evolution reaction and glycerol oxidation reactions via tunning the reaction pathway. This study provides a scientific insight into developing future reaction switch for electrocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • For the Cu 7 M, Cu 8 M, and Cu 9 M atomic clusters, the M metal atoms tend to be centered. • We found that the addition of transition metals enhanced the stability of clusters. • The addition of transition metals increased the adsorption energy of CO 2 clusters. • In the reaction of catalytic CO 2 reduction, CunNi was found to be the preferred catalyst. The efficient and selective electroreduction of CO 2 in chemical fuels can be environment-energy friendly; however, it highly relies on catalysts with controllable selectivity and reaction paths. At present, copper-based catalysts are a good option for CO 2 reduction, and the formation of C 1 + products is presented in this paper. First, we systematically studied the three-dimensional structures of the Cu 4-12 M clusters (a total of nine types). The M atoms were sequentially replaced by first-row transition metals (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn), which enhanced the stability of the clusters and their CO 2 adsorption energy. Second, studies on the catalytic reduction of CO 2 indicated that these clusters tend to produce methane through pathways mediated by CHO*. Finally, we summarized the lowest rate-determining steps of all clusters and identified the most suitable catalyst candidates. This work advances the theoretical study of nanoclusters for catalytic CO 2 reduction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electrical conduction of cluster-assembled Sn films is studied during film growth. • Coalescence phenomena impact on film morphology and percolation threshold. • Deposition rate enables the tuning of percolation threshold. • Resistivity vs. thickness exhibits a power-law trend, as per ballistic growth. The electrical conduction of nanostructured Sn films assembled via Supersonic Cluster Beam Deposition is studied in-situ during film growth. The kinetic energy of Sn nanoparticles, in combination with low melting point of Sn, promotes coalescence phenomena, enabling the investigation of their impact on film morphology and on percolation threshold. A percolation threshold occurring at thicknesses much larger than the dimensions of Sn nanoparticles suggests that coalescence leads to the growth of disconnected, island-like structures. The deposition rate is found to influence coalescence dynamics during the early stages of film growth, allowing for the tuning of film microstructure from a more compact, island-like morphology to a more porous structure. The percolation threshold shifts accordingly from 24 nm to 3 nm film thickness. Upon completion of the percolation phase, film resistivity settles at values 2–3 orders of magnitude larger than that of bulk Sn, attributed to the nanogranular nature of cluster-assembled films. During the "3D conduction" phase, resistivity exhibits an increasing trend with thickness following a power law with an exponent value of 0.76–0.78. This behavior is attributed to the decrease in the density of interconnections between particles in the topmost layer during film growth, consistent with expectations in ballistic growth processes. [ABSTRACT FROM AUTHOR]

We analyze the surface tension in ultra-cold atomic gases in a quasi one-dimensional and one-dimensional geometry. In recent years, experimental observations have confirmed the "clustering of atoms" to form droplets in ultra-cold atomic gases and the emergence of this new phase is attributed to the beyond mean-field interaction. However, two decades earlier, liquid formation was predicted due to the competition of two-body and three-body interactions. Here, we review both propositions and comment on the role of beyond mean-field and three-body interaction in liquid formation by calculating the surface tension. • We have obtained cnoidal solutions at lower dimensions in presence of different nonlinearities. • We calculate the surface tension in both the dimensions. • We observe external potential plays a pivotal role for non zero surface tension. • In quasi one-dimension, surface tension is independent of beyond mean-field interaction. • In one-dimension, surface tension is independent of three body interaction. [ABSTRACT FROM AUTHOR]

The synergistic collaboration between oxygen vacancies (O V) in the atomic Fe-oxide clusters and the adjacent Ni(OH) x resulted in the quantum leap of the CO 2 methanation performance of the NiFe-TiO 2 catalyst. [Display omitted] • Incorporation of atomic Fe oxide clusters induces oxygen vacancies both in atomic Fe-oxide clusters and Ni(OH)x. • Collaboration between oxygen vacancies and neighboring atoms facilitates CO 2 methanation performance of Ni(OH)x. • This material delivers the CH 4 productivity of ∼24,358 mmol g-1h−1 at 300 °C. • It shows no degradation in the stability test up to 330 h. The heterogeneous catalytic conversion of carbon dioxide (CO 2) to methane (CH 4) via CO 2 methanation offers a promising avenue for establishing the closed carbon loop. Nevertheless, the lack of effective catalysts limits its industrial applications. Considering this, we developed a novel heterogeneous catalyst comprising oxygen vacancies enriched atomic Fe-oxide clusters confined in the TiO 2 -supported Ni-hydroxide (denoted as NiFe-TiO 2) via wet chemical reduction method. This material delivers an unprecedently high CH 4 productivity of ∼24,358 mmol g-1h−1 in CO 2 methanation at 300 °C, surpassing the Ni-TiO 2 (12,481 mmol g-1h−1) by ∼ 95 %. On top of that, the high structural reliability of the Fe-oxide atomic clusters endows the NiFe-TiO 2 catalyst with outstanding durability, where it achieves an optimum CH 4 productivity of ∼ 36,399 mmol g-1h−1 after 116 cycles (155 h) with CH 4 selectivity of 90.5 % and retains the pristine performance up to 220 cycles (330 h) in the stability test. With evidence from in-situ X-ray absorption and ambient pressure X-ray photoelectron spectroscopy studies, the performance descriptors and reaction pathways were unveiled, where the oxygen vacancies in the atomic Fe-oxide clusters and the adjacent Ni-hydroxide domains synergistically boost the CO 2 activation and the H 2 dissociation, respectively. Such a potential synergy enables the simultaneous operation of all intermediate steps for enhanced CO 2 methanation kinetics on the NiFe-TiO 2 surface. Most importantly, these findings not only unravel the merits of oxygen vacancies in transition metals for CO 2 methanation but mark a step ahead for the rational design of heterogeneous catalysts in various catalytic applications. [ABSTRACT FROM AUTHOR]

• A MXene/VS4 composite electrode was fabricated and utilized in a high-performance aqueous zinc ion flexible supercapacitor. • The electrode exhibited excellent electrochemical performance and flexibility, achieving a significant improvement in electrochemical performance while maintaining the flexibility of MXene. • The prepared supercapacitor retained 91.9% of its initial capacitance after undergoing 2000 bending cycles, demonstrating its outstanding mechanical stability. MXene materials, with their high electrical conductivity, pseudocapacitive energy storage mechanism, and high flexibility, are considered as highly potential materials for flexible supercapacitors. However, the strong inhibition of ion storage and transportation caused by the inherent stacking effect of the material limits its application. This issue can be effectively addressed by intercalating an interlayer agent. VS 4 , which serves as an excellent interlayer agent, has a larger interatomic spacing between atomic clusters in the crystal (5.6 Å) compared to the interlayer spacing of MXene. This facilitates the movement of ions, enabling them to traverse the material more freely. Furthermore, VS 4 exhibits a more negative adsorption energy than MXene, making it easier for MXene to adsorb VS 4. Therefore, we designed an MXene/VS 4 composite electrode with good electrochemical performance and flexibility. Based on this composite electrode, we prepared a high-performance aqueous zinc ion flexible supercapacitor. Specifically, it exhibited a maximum power density of 13.33 W cm−3, an energy density of 39.88mWh cm−3 and a high capacitance retention of 88.5 % of its initial capacitance after 10,000 cycles. Even when bent to 150°, the capacitance retention of this flexible supercapacitor remained at 79 % of the initial value. Furthermore, after 2000 bending cycles, the supercapacitor retains 91.9 % of its initial capacitance. [ABSTRACT FROM AUTHOR]

• Primary phase is mainly combined by stable FCC atoms with few metastable BCC atoms under slow cooling rate. • Primary phase is mainly combined by stable FCC atoms and metastable BCC phase under fast cooling rate. • Metastable BCC phases gradually transform into stable FCC phases during the growth process under fast cooling rate. • Much more ICO-like atomic clusters in undercooled liquids is favorable to the formation of metastable BCC phase in primary nuclei. The formation and evolution of metastable BCC phase during the solidification of CoCrFeNi HEA is studied by molecular dynamics (MD) method. It is found that the primary phase is mainly combined by stable FCC atoms under the cooling rate of 0.5 K/ps, while few metastable BCC atoms are observed during the nucleation and growth process. Under the cooling rate of 0.5 K/ps, the metastable FCC nuclei inside with bulk BCC structures and HCP twinning planes are formed during the primary nucleation and the metastable BCC phases gradually transform into stable FCC phase during the growth of nuclei, and few BCC phases is retained in the solidified solids. It is also found that the volume fraction of metastable BCC phases decreases with the reduction of cooling rate, and the formation and evolution of metastable BCC phases in CoCrFeNi HEA are different from that in some conventional metals and alloys. [ABSTRACT FROM AUTHOR]

Dislocations are common line defects in the preparation and irradiation processes of tungsten (W), and they can serve as trapping sites for hydrogen (H) and helium (He) atoms. Existing studies have indicated that dislocations preferentially capture He atoms to form dislocation-He cluster structures. The focus of this study was on the effects of this new structure on the trapped and diffusion behavior of H atoms using molecular dynamics (MD) method. The study considered the number of He atoms from 1 to 150, and they were classified as small He cluster and large He cluster. By calculating the binding energy, the study revealed that the capture strength is positively correlated with the He clusters' size. However, it is negatively correlated with the distance from the dislocation core and the captured H atoms' number. This study output the stable configurations to analyze the growth patterns of He cluster in dislocations, and it was observed that the interstitial atoms caused by trap mutation preferentially aggregate into dislocation loops due to the dislocation core structure. Moreover, the study investigated the diffusion behavior of H atoms around the dislocation-He cluster structure at 600 K within 1 ns. The hydrogen atoms tend to migrate towards the He cluster and distribute around it uniformly. The distribution range narrows with the helium cluster's size, and the distribution pattern depends on the dislocations' type. This demonstrated the formation of dislocation-He cluster structure, promoting the increased H retention. [ABSTRACT FROM AUTHOR]

[Display omitted] • After the dissociation and diffusion of H 2 , the spillover of H atoms and H clusters is formed. • H cluster facilitated C-O bond scission to easily form H ligand co-bonded to metal. • There are four potential driving forces capable of dissociating CO 2. • Out of the various forces, atomic H is the most dominating force for the dissociation of CO 2. • The active sites and metal species strongly influence CO 2 dissociation route. The study of carbon dioxide (CO 2) methanation mechanisms widely argues on the nature and formation of intermediates. How reactants dissociate is still poorly understood. To gain deeper knowledge on its mechanism, we focused on studying reactants dissociation. After H 2 dissociation and diffusion, the spillover H atom was observed, as well as the confirmation of H cluster formation on metal through aggregation by simulation and experiment. This H cluster facilitated C-O bond scission to easily form H ligand cobonded to metal, and thus resulted in high CO 2 methanation performance. Four driving forces could dissociate CO 2 , three of them came from supports and metals, and another one was atomic H on metal as the strongest force. This simple and convenient method has wide adaptability and can be developed as an effective standard method for studying CO 2 dissociation. The facile dissociation study of reactants would be very helpful in understanding the CO 2 hydrogenation mechanism. [ABSTRACT FROM AUTHOR]

The adsorption behavior of small thiol-protected gold cluster Au 12 (SCH 3) 9 + to temozolomide has been investigated under different environmental conditions. [Display omitted] • The adsorption behavior of small thiol-protected gold cluster Au 12 (SCH 3) 9 + to temozolomide has been investigated using density functional theory. • The newly generated Au–O and Au−N bonds in TMZ-Au 12 (SCH 3) 9 + exhibit ionic characteristics. • The change in solvent is beneficial for adjusting the interaction strength and mode between TMZ and Au 12 (SCH 3) 9 +. The adsorption behavior of a thiol-protected gold cluster Au 12 (SCH 3) 9 + to temozolomide (TMZ) has been investigated at the M06-2X-D3/6-311G(d, p)&LanL2dz//B3LYP-D3(BJ)/6-31G(d,p)&LanL2dz. Results show that TMZ prefers to combine with the central Au atom in the Au cluster via its O and N atoms, forming ionic Au–O and Au–N bonds, respectively. The calculated adsorption energies of TMZ on Au 12 (SCH 3) 9 + are − 44.43, −12.27, −43.59, and −10.01 kcal·mol−1 in the gas phase, water, acetic acid, and dimethyl sulfoxide, respectively. The interaction strength and mode between the TMZ drug and Au 12 (SCH 3) 9 + vary with different solution environments. Therefore, the solvent could influence the interaction of TMZ-Au 12 (SCH 3) 9 + complexes. Such a property of TMZ–Au 12 (SCH 3) 9 + could be applied to drug-delivery processes, which might contribute to improving the efficiency of this drug and reducing its toxic and side effects. Based on the natural population analysis and QTAIM analysis, noticeable charge transfer from TMZ to the Au cluster was observed, increasing the dipole moments of TMZ–Au 12 (SCH 3) 9 + complexes. We believe that this work could extend the applications of small Au-based clusters, especially thiol-protected gold clusters in drug-delivery processes. [ABSTRACT FROM AUTHOR]

An all-electron calculation on Be n Si (n = 1–12) clusters has been performed by using density functional theory with the generalized gradient approximation at the PW91 level. The results reveal that the lowest energy geometries of Be n Si (n = 1–12) clusters may be generated by substituting a Si atom for one Be atom of the Be n +1 clusters. In addition, Si atom tends to occupy external locations of main Be n clusters and bonds with multiple Be atoms in the Be n Si (n > 2) clusters. The average binding energy of Be n Si clusters is higher than that of pure Be n +1 clusters, indicating that the doped of the Si atom enhances the cluster's binding force. Compared with pure Be n +1 clusters, the HOMO-LUMO GAP of Be 7 Si, Be 8 Si, and Be 10 Si clusters increase while the HLG of other Be n Si clusters(n = 1–3,5,9,11,12) decreas. The vertical ionization potential and vertical electron affinities curves of clusters have the same general trend. The VIP of the cluster decreases gradually while the VEA increases gradually. The doping of the Si atom greatly influences the stability of pure Be n clusters, and the analysis of energy and electronic properties of Be n Si clusters reveals that the Be 3 Si cluster is the magic number structure in the system. [ABSTRACT FROM AUTHOR]

• The removal of BrO 3 − could proceed on Pt clusters rather than the single atoms. • H 2 was dissociated in a heterolytical manner on the isolated Pt atoms. • The reduction of BrO 3 − and high-valent Mo need consecutive active H. • The introduction of Mo promoted BrO 3 − reduction remarkably. • The co-anions had faint effect on BrO 3 − removal. Here, we prepared microporous carbon (PC) supported Pt catalysts with different isolated Pt atoms and designed pathways to introduce Mo into the catalysts. Bromate (BrO 3 −) was applied as the model oxyanion to evaluate the hydrogenation decontamination efficiency and catalyst activity. At a catalyst dosage of 0.05 g l−1, BrO 3 − was reduced by 98.3 % after reaction for 30 min over Pt 2 -PC with Pt atomic clusters, much higher than that of single atom (Pt 0.5 -PC, 5.1 %) and nanoparticle (Pt n -PC, 43.2 %) counterparts. H 2 was dissociated in a heterolytical manner on the highly isolated Pt active sites and the formed active H+/H− pairs dominated the removal of BrO 3 − supported by the experimental data and density functional theory (DFT) calculation. High-valent Mo in the solution could be reduced to lower valent by consecutive active H, which further joined BrO 3 − reduction directly. In comparison, Mo atoms anchored on PC substrate scrambled N ligands with Pt, favoring the enrichment of BrO 3 − anions on the catalyst surface, thus the generated active H could react with the nearby BrO 3 − instantly. This study highlights the role of few-atomic Pt clusters for H 2 activation and provides a strategy to boost the liquid phase catalytic hydrogenation reaction. [ABSTRACT FROM AUTHOR]

Chemical mechanical polishing (CMP) is a widely utilized technique for achieving ultra-smooth surfaces, yet a comprehensive understanding of the surface microtopography evolution remains elusive due to the intricate chemical and mechanical interactions inherent in chemical mechanical polishing. Accordingly, this study explores the evolution law of different spatial frequency features of surface microtopography of monocrystalline silicon by analyzing the changes in the power spectral density (PSD) curve. More importantly, the evolution mechanism of the chemical mechanical polishing surface micromorphology is revealed through the analysis of the power spectral density under different mechanical and chemical conditions. The results emphasize the noticeable impact of both mechanical and chemical actions on the evolution of different spatial frequency features in surface microtopography. The mechanical action of a large particle, less likely to contact the valley region with a small curvature radius, enhances the smoothing speed of high-spatial frequency roughness. Moreover, the mechanical action of polishing pad demonstrates a greater efficiency in smoothing mid-spatial frequency roughness when utilizing a hard pad. This is attributed to the limited impact of pad hardness on the removal depth of single particles within the reaction layer, rendering it less significant for high-spatial frequency roughness. Upon elevating the chemical reaction rate, a notable acceleration in the reduction of roughness in both mid- and high-spatial frequency regions is observed. Furthermore, insights derived from molecular dynamics (MD) simulations of monocrystalline silicon and quartz glass show that the manner of surface atom removal, whether through single atom removal or cluster removal, exerts a significant effect on the final high-spatial frequency components of the power spectral density. This study contributes valuable insights into the intricate formation mechanism of a smooth surface in chemical mechanical polishing. [Display omitted] • The surface microtopography evolution of monocrystalline silicon was studied by analyzing the PSD curve. • The difference in the evolution between mid- and high-spatial frequency roughness was explained. • The same depth of particle removal was achieved under different pad hardness due to reaction layer constraints. • The final high-spatial frequency roughness varied due to difference in atomic removal forms. [ABSTRACT FROM AUTHOR]

[Display omitted] • Adsorption properties of atrazine with Ag, Au, Cu and their mixed clusters are experimentally and theoretically. • The size of the atoms in the cluster significantly influences the NCI, ELF and LOL studies indicate significant electron delocalization around the metal clusters and CPD. • Clustering of CPD with metal cages results in the enhancement of Raman signals due to SERS activity. • Wavefunction based analysis indicated that there are significant non-covalent interactions between the system and the metal clusters. Investigation of the adsorption properties of a herbicide, atrazine (6-chloro-4- N -ethyl-2- N -propan-2-yl-1,3,5-triazine-2,4-diamine) (CPD) with Ag, Au, Cu and their mixed clusters are presented using density functional theory (DFT) analysis. With metal clusters, it is found that CPD forms stable clusters, the drug-cluster complexation energy is maximum in CPD-Au 2 Cu (−38.69 and −45.79 kcal/mol) in vacuum and aqueous phase in comparison with other clusters. Dipole moment of the CPD-metal systems is higher than that of CPD. Clustering of CPD with metal cages enhances the Raman signals due to surface enhanced Raman scattering (SERS) activity. The exothermic processes and fluctuations in entropy during the processes were altered for all clusters as a result of CPD adsorption to the cages, indicating a change to a more ordered structure. Wavefunction based analysis indicated that there are significant non-covalent interactions (NCIs) between the system and the metal clusters. [ABSTRACT FROM AUTHOR]

In this study, we report an ultra-precision nonsubtractive surface polishing technique named plasma-induced atom migration manufacturing (PAMM). In PAMM, the molten layer of the fused silica surface can be formed owing to the energy transmitted by inductively coupled plasma (ICP) which has a high gas temperature and radical density. The smoothing of surface is attributed to the rearrangement of surface atoms or clusters driven by surface tension. Unlike conventional subtractive smoothing processes, PAMM removes no material and can achieve damage-free surface with high efficiency and low cost, which makes it a promising technique to obtain large optical components with excellent optical performance and long operation life. The static and scanning smoothing characteristics of PAMM were presented and the surface smoothing mechanism was discussed. By this method, an ultrasmooth surface with Sa roughness of 0.15 nm was achieved. Furthermore, the validity of PAMM of spherical surface polishing and damaged surface recovering of fused silica was experimentally verified. • PAMM was proposed as a nonsubtractive ultra-precision smoothing technology. • ICP torch was characterized by high temperature and high particle density. • PAMM could quickly smooth a ground fused silica surface to reduce Sa from 86.57 nm to 0.15 nm. [ABSTRACT FROM AUTHOR]

Templated growth of monodisperse metal nanoclusters has successfully been realized through graphene moiré patterns on transition metal substrates, but the underlying mechanism is still unclear. Herein, based on first-principles calculations, we systematically study the growth mechanism of Pt and Au nanoclusters on graphene-covered Ir(111) substrate. Our results indicate that the induced sp2-sp3 rehybridization of C atoms plays a key role for the templated growth. From the center of the template to the outside, such rehybridization is gradually suppressed due to the enlarged horizontal distance between C atoms and the adjacent Ir atoms, which causes weaker bonding of Pt atoms to larger clusters and thus the perfect templated growth. Meanwhile, negligible sp2-sp3 rehybridization is observed due to the weak adsorption of Au atoms on graphene, which leads to the failure of the template. This mechanism is then extended to other metal nanoclusters successfully. We believe that it will help to understand the structure-activity relationship of more two-dimensional templates. [Display omitted] • The growth mechanism of metal nanoclusters on graphene moiré patterns is revealed. • The template effect is caused by the sp2-sp3 rehybridization of C atoms. • Our simulations are in good agreement with a series of experimental observations. [ABSTRACT FROM AUTHOR]

Treating and recycling high concentration acetic acid in the exhaust water has long posed a challenge in industry. These wastes containing acetic acid are typically processed via basic neutralization, characterized by high acidity and resistance to degradation, which can bring potential economic burden and environmental hazards. Here we report a new photocatalytic conversion route for addressing high concentrations of acetic acid. This process transforms acetic acid into valuable succinic acid through dehydrogenative coupling. Additionally, the photocatalytic conversion of acetic acid exhibits structure sensitivity when employing Pt cocatalysts of varying sizes. Through inhibiting the undesirable H termination of active free radicals over small Pt atoms and clusters, the rate of undesired decarboxylation reactions can be decreased by 75 %. This effectively enhances the selectivity of the coupling product succinic acid by 2.1 times, achieving a succinic acid formation rate of 7.28 mmol/(g cat •h). This work offers a theoretical guidance for searching value-added reaction pathways of acetic acid, thereby establishing an innovative approach for high concentration exhaust acetic acid treatment and converting low value monocarboxylic molecules into valuable diacid polymerization monomers under a mild and green condition. [Display omitted] • A novel synthesis route of succinic acid via a light-driven dehydrogenative coupling reaction. • The formation rate of succinic acid is 7.28mmolg cat −1h−1, AQY=9.95 %, ATOF=14855 h−1. • The photocatalytic conversion of acetic acid exhibits structure sensitivity. • The rate of undesired decarboxylation reactions can be decreased by 75 %, Selectivity increased by 2.1 times, through inhibiting the undesirable H termination of •CH 2 COOH radicals. [ABSTRACT FROM AUTHOR]

The Ovonic Threshold Switching (OTS) selector serves as an essential component in the development of three-dimensional high-density memory integration technology. Nevertheless, the state-of-the-art high-performance OTS materials usually contain toxic elements such as arsenic (As), posing significant risks to both environmental and human health. Nitrogen (N), which belongs to the same group as arsenic (As), has emerged as a highly promising alternative for As doping. However, the underlying mechanisms that govern N-based OTS materials have not yet been extensively investigated. In this study, we delve into the effects of N doping on the structural, bonding, and electronic properties of amorphous GeSe (a-GeNSe) by ab initio molecular dynamics simulations to bridge the knowledge gap. Our findings indicate that upon N doping in a-GeSe, the formation of robust Ge-N bonds, along with N-centered tetrahedral and triangular structures, resulting in the sluggish atomic movement that enhances the thermal stability and endurance of a-GeNSe. The OTS characteristics are significantly influenced by the material's electronic band structure, and thus the relatively slow performance drift can be attributed to the stabilization of mid-gap states, a result of N doping which effectively slows down the aging process of chalcogenide glass. Moreover, the increased mobility gap in a-GeNSe raises the threshold voltage (V th), making it more compatible with commercially available phase-change memory materials. Our findings reveal the extensive impact of the N element on a typical OTS material and offer valuable perspectives for alternative doping strategies that could potentially supplant As practices. • The structural, bonding and electronic properties of amorphous (a-) GeNSe alloy were comprehensively investigated. • The atomic-level mechanisms of high thermal stability and high threshold voltage (Vth) were discovered. • The atomic clusters contribution of mid-gap states for OTS behavior after N doping was uncovered. • The structural origin of low Vth drift for a-GeNSe materials were revealed. [ABSTRACT FROM AUTHOR]

• An anomaly of resistivity behaviour in Fe-18.5 Ga alloy. • Change of the unit cell lattice parameter. • In situ neutron diffraction, magnetization, dilatometry and positron annihilation. • Formation of D0 3 -type ordered cluster-like zones in metastable A2 structure. The results of high-precision electro-resistivity measurements, ρ (T), for Fe-18.5%Ga alloy over a wide temperature range are presented. An anomaly in the ρ (T) temperature behavior is detected and it is proved that it correlates well with the change in the unit cell lattice parameter of the alloy and with the results obtained from measuring magnetization, dilatometry and positron annihilation. From the neutron diffraction data, it follows that the detected anomaly is associated with the formation of a cluster-like microstructure of the alloy: in the structurally disordered A 2 matrix, regions with partially ordered D 0 3 phase are formed. Interpretation of this non-monotonic behaviour of ρ (T) is discussed. [ABSTRACT FROM AUTHOR]

• Pd-based catalysts consisting of single Pd atom, sub-nanometer Pd clusters, and Pd nanoparticles were successfully synthesized. • Single Pd atoms, sub-nanometer Pd clusters, and Pd nanoparticles anchored on nitrogen-doped carbon for Heck reactions were investigated. • Ensemble Pd clusters of an approximately 1.6 nm are the most reactive structures for Heck reactions. We reported a series of nitrogen-doped carbon-supported palladium (Pd) species with various sizes for the Heck reaction of iodobenzene and methyl acrylate. By precisely controlling the synthesis procedure, we have successfully synthesized a range of Pd-based catalysts, including single Pd atom, sub-nanometer Pd clusters (∼ 0.4 nm, and ∼1.6 nm), and Pd nanoparticles (∼5.8 nm and 10 nm). Remarkably, these catalysts exhibit a distinct size-dependent catalytic activity in the Heck reaction. In the case of the Heck reaction of 4‑methoxy-iodobenzene and methyl acrylate, the Pd-10 site demonstrated the highest site-specific turnover frequency (TOF), reaching 792.5 h −1. This performance is impressively 5.2 and 15.6 times superior to that of the Pd 1 site (152 h-1) and Pd-10 site (50.6 h-1), respectively. Significantly better in the Heck reactions with other aryl halides were achieved with Pd-1.6/N-C (comprising of approximately 1.6 nm-sized Pd clusters), compared to those containing 10 nm-sized nanoparticles (Pd-10/N-C) or Pd 1 /N-C. These findings suggested that Pd clusters of around 1.6 nm may serve as the potential catalytic sites for the Heck reaction. [ABSTRACT FROM AUTHOR]

Gas sensors are the key equipment in transformer fault online monitoring systems, and developing new and efficient gas sensing materials is an important prerequisite for breaking through existing monitoring performance. Herein, the first-principles density functional theory (DFT) is employed to study the adsorption and gas-sensing performance of two metal atomic clusters (Pt 3 and Rh 3) anchored on a WTe 2 monolayer (C-WTe 2) for four typical fault characteristic gases (CO, CO 2 , H 2 , and C 2 H 2). These results suggest that four gases can stably bind to C-WTe 2 and exist in the form of chemical adsorption due to the high adsorption energy. Also, Rh 3 -WTe 2 exhibits high selectivity and repeatability towards CO and CO 2 due to its strong response and fast recovery characteristics when used in resistive sensors; Pt 3 -WTe 2 can detect and distinguish the four types of gases due to the significant and differentiated changes in work function when used in work function sensors. Therefore, both Pt 3 -WTe 2 and Rh 3 -WTe 2 monolayers are promising gas-sensing materials for the dissolved gases detection in oil. This investigation sheds light on devices of designing metal atomic cluster anchored WTe 2 -based gas sensor for improved transformer fault monitoring performances. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Al vacancies induce the presence of high-load Pt in the form of low-coordinated clusters on the surface of LDO 5. • Pt/LDO 5 exhibits superior low-temperature catalytic oxidation activity for HCHO compared to Pt/LDO. • Both Al vacancies and Pt clusters can enhance the spin state of Co species in the support. • The direction of electron transfer between Pt clusters and the support is regulated by Al vacancies. Noble metal loading and oxygen vacancy construction are prevalent strategies to enhance catalyst performance in HCHO catalytic oxidation. For noble metal systems, most cutting-edge research focuses on single atoms, including the exploration of coexistence between single atoms and clusters, yet there are few reports on the impact of noble metal clusters with different coordinations on catalyst performance. Additionally, investigations into metal vacancies, as opposed to oxygen vacancies, are also scarce. In this work, we used CoAl layered double hydroxides (LDHs) as a precursor, which, after calcination and etching, yielded derived oxides with Al vacancies (LDO 5). Pt was then loaded onto the surface of these oxides via impregnation (Pt/LDO 5). Activity tests demonstrated that Pt/LDO 5 exhibited superior HCHO oxidation activity, especially at low temperatures, compared to Pt/LDO. Utilizing high-resolution transmission electron microscopy (HRTEM) and X-ray absorption fine structure (XAFS), we discovered that, in contrast to the "standard" Pt clusters on the LDO surface, Pt primarily existed as low-coordination clusters on the LDO 5 surface, even with a higher Pt loading. Moreover, the coexistence of Al vacancies and low-coordination Pt clusters effectively enhanced the spin state of Co species in the support and altered the direction of electron transfer between Pt and the support. [ABSTRACT FROM AUTHOR]

Formic acid is a high-prospect energy carrier of sustainable H 2 and can also favorably supply sustainable H 2 to hydrogenation catalysts in replacement of external pressurized H 2. A solar photon-assisted synthesis method was successfully implemented for decorating a ceria-modified TiO 2 support with ultra-dispersed Ru nanoclusters with a large fraction of low atomicity species and Ru single atoms. Adding ceria to the TiO 2 support at a quarter of the theoretical monolayer is a suited surface modification for partially reducing the detrimental intrinsic activity of the bare TiO 2 surface for the dehydration of formic acid, what allows the undesired formation of CO to be mitigated and higher selectivities to H 2 to be achieved when using the Ru/CeO 2 /TiO 2 catalyst. The dual (combined) photonic/thermal excitation of the Ru/CeO 2 /TiO 2 catalyst boosted the H 2 production rate and allowed the dehydrogenation reaction to be conducted at a lower temperature compared to the dark conditions, for instance with a 80°C downshift at 190°C, what corresponded to a 42 % relative gain compared to the dark conditions. Advanced electron microscopy characterization has been crucial to unveil the atomic-level nature of the Ru/CeO 2 /TiO 2 photo-thermo catalyst, bringing to light the presence of ultra-dispersed metallic Ru nanoclusters, both (i) decorating nanometric-sized flat CeO 2 nanoparticles interfaced in epitaxy with high-index TiO 2 facets, and (ii) being homogeneously distributed over the TiO 2 surface in close vicinity with low atomicity CeO 2 species. [Display omitted] • CeO 2 nanoparticles and clusters electronically modify TiO 2 surface. • Advanced electron microscopy reveals Ru single atoms and clusters. • Ru/CeO 2 /TiO 2 catalyst outperforms Ru/TiO 2 reference in dehydrogenation reaction. • Ceria-based nanostructures partially inhibit CO formation, boosting H 2 selectivity. • Dual photonic/thermal excitations improve the HCOOH decomposition. [ABSTRACT FROM AUTHOR]

[Display omitted] • Doping of atomic cluster Mo 3 can weaken the adhesion of H 2 O molecule on Mo 3 -TiS 2 monolayer. • The surface of Mo 3 -TiS 2 monolayer can generate a large amount of chemically adsorbed oxygen. • Mo 3 -TiS 2 monolayer has the ability to detect SO 2 in real-time at low temperatures. Monitoring the SF 6 decomposition gas (DPA) by gas sensors can be used to predict the operating status of power equipment, and the sensitivity performance of gas sensors is deeply influenced by the humidity resistance and surface oxygen adsorption performance of their sensing materials. The present research aims to explore a high‐valence transition‐metal ion doped transition metal dichalcogenide (TMD) monolayer that hosts high moisture resistance and abundant surface-chemisorbed oxygen suitable for detecting DPA. Using first-principles methods, the adsorption behavior of three representative types of gases (HF, SO 2 , and CO 2) in DPA, H 2 O, and O 2 on Mo 3 -TiS 2 monolayer are considered. Our results show that SO 2 and CO 2 molecules are adsorbed above the Mo 3 cluster through chemical adsorption, while HF molecule is physically adsorbed. The desorption times for SO 2 and CO 2 on Mo 3 -TiS 2 adsorbent are 9.89 s at 348 K and 34.96 s at 398 K, respectively. Introducing dopant Mo 3 resulted in better anti-humidity performance of TiS 2 , as the force of Mo 3 -TiS 2 monolayer towards H 2 O molecule is weakened compared to the intrinsic adsorption system. Additionally, Mo 3 -TiS 2 monolayer exhibits an exceptionally high affinity for O 2 molecule, leading to the rupture of chemical bond in O 2 , and the chemisorbed oxygen ions are acquired through the charge transfer between Mo 3 cluster and O 2 molecule. The computational findings in this article offer theoretical backing for advancing the development of gas sensors utilizing Mo 3 -TiS 2 and its utilization in the realm of DPA detection. [ABSTRACT FROM AUTHOR]

Germanium, gallium, nitrogen, and oxygen deposition on both GaN(0001) and GaN(000 1 ̄) surfaces were investigated. A multiscale simulation framework was implemented. The DFT simulations were employed to reveal the interactions among the species and GaN surface. Energy diffusion barriers were obtained by the Nudged Elastic Band approach. A Poisson–Nernst–Planck model was implemented to calculate the concentration of each atomic species near GaN surface. The kinetic and unimolecular collision gas theories were incorporated to determine adsorption rates. These outcomes were integrated into a nanoscale kinetic Monte Carlo model. This model allowed to generate data on the surface diffusion and clustering of adsorbed atoms on GaN surfaces. As a result, an enhanced understanding of the deposition and agglomeration mechanisms was achieved. In particular, of the roles played by germanium and oxygen. Due to the relatively high diffusion energy barriers, germanium atoms act as pins around to which gallium atoms tend to cluster. The results align with both experimental observations and existing simulation literature. To the best of our knowledge, no previous DFT simulation results on germanium deposition on GaN have been reported. [Display omitted] • DFT calculations show that the Ga-polar is the most stable GaN surface. • The kinetic Monte Carlo simulations indicate that Ga and Ge tend to agglomerate. • Formation of Ge and Ga islands depends upon physical parameters. • The continuum scale gives realistic ions concentration near the adsorption layer. • TThe framework sheds light on the interfaces formation for power electronic devices. [ABSTRACT FROM AUTHOR]

The mechanical properties of open-cell aluminum foams can be influenced by enhancing the microstructure of the struts. The foams produced by investment casting face slow cooling rates, which makes it challenging to improve the morphology of the phases. In the case of aluminum silicon cast foams, the silicon phase accumulates on the surface of the struts, which leads to brittle fractures. In the present study, we successfully modified the silicon phase in open-cell AlSi7Mg and AlSi10Mg cast foams by adding strontium and investigated the influence of the strontium content on the microstructure and mechanical properties at the foam and strut levels. Despite the cooling rates of less than 0.5 °C/s during solidification, the strontium addition of 200–800 ppm effectively decreased the size of the silicon particles and improved their distribution in the micrometer-sized struts. Improvements in the compressive properties of the foams and the tensile properties of the struts only occurred at the strontium levels of 200 and 400 ppm. The effective modification in this casting condition is due to the limited solidification space, which favors the formation of the atomic clusters responsible for the modification. • Strontium modifies eutectic silicon in cast aluminum foams even at slow cooling rates during solidification below 0.5 °C/s • Possibility of higher modification efficiency in confined solidification spaces such as micrometer-sized foam struts • 3D morphology of eutectic silicon phase in Al-Si alloy observed under modified and unmodified conditions • Sr addition (max 400 ppm) enhances peak/plateau compressive stresses, UTS, and deformation strains in Al-Si foams [ABSTRACT FROM AUTHOR]

In this work, we performed first-principles calculations to study the interactions of Ni n clusters (n = 2-5) with graphene. Ni n clusters were adsorbed on pristine graphene and graphene with a vacancy. We observed that the adsorption energy is significantly lowered when graphene has a single vacancy. The single vacancy gives place to a charge redistribution that favors chemisorption. The dangling bonds of the carbon atoms produced by the vacancy increase the magnetic moment of the C atoms around the hole induced by the Ni clusters. We found that the situation is very different when the Ni cluster is adsorbed with atoms on both sides of the vacancy. We consider the cases in which one of the Ni atoms is located on one side of the graphene sheet and the rest on the other, Ni n , 1. The adsorption energy for Ni 3 , 1 and Ni 4 , 1 clusters are slightly larger than when the whole cluster is chemisorbed on one side only, but the charge redistribution, occurring on both sides of the graphene, increases the possibility to adsorb other molecules. For all cases, we analyzed the electronic density of states to account for the electronic changes on the graphene sheet as a function of the size of the Ni n cluster. Finally, the Bader effective charges were computed to follow the charge transfer between Ni n clusters and the graphene atoms. • Ni n adsorbs stronger on graphene pristine as n increases; the opposite occurs for graphene with a vacancy. • The d z 2 states from Ni hybridize with p z from C atoms. • QTAIM methodology was used to analyze the charge transfer between Ni and C atoms. [ABSTRACT FROM AUTHOR]

• P has opposite effects on high and low temperature viscosity of Fe-C-Ti-P melts. • Solid phase particles effects the viscosity within the solid–liquid phase region. • Cluster characteristics determines the viscosity in the liquid phase. • P promotes the solid particle precipitation in solid–liquid phase region. • P depolymerizes the medium-range ordered structures in liquid region. This study systematically investigates the underlying principles and mechanisms governing viscosity across the entire range for the Fe-4.5C-0.1Ti-xP (in wt.%) melts. The viscosity profile exhibits distinct variations in different phases. In the solid–liquid transition region, the primary determinant of viscosity is the presence of solid phase particles, while in the region characterized by liquid phase, the primary influencing factor is the number of clusters. Notably, the impact of P content demonstrates a contrasting effect on low-temperature solid phase precipitation and high-temperature liquid phase structure. During the low-temperature solid phase precipitation stage, an increase in P content serves as a catalyst for graphite precipitation, resulting in an increase in system viscosity and, by extension, impacting an increase in system viscosity. In contrast, within the high-temperature liquid phase, the interaction of P with iron (Fe) results in the breakdown of mid-range clusters in the original system, leading to the formation of smaller clusters with a reduced overall cluster volume. Consequently, an increase in P content is associated with a decrease in viscosity. These findings provide a nuanced understanding of the interplay between P content and viscosity throughout different phases of the melt. [ABSTRACT FROM AUTHOR]

Deformation behaviour of multicomponent metallic glasses are determined by the evolution/reconfiguration of the short- and medium-range order (SRO and MRO) atomic structures. A precise understanding of how different atom species rearrange themselves in different stress states is still a great challenge in materials science and engineering. Here, we report a systematic and synergetic research of using electron microscopy imaging, synchrotron X-ray total scattering plus empirical potential structure refinement (EPSR) modelling to study in situ the deformation of a Zr-based multicomponent metallic glassy alloy with 5 elements. Systematic and comprehensive analyses on the characteristics of the SRO and MRO structures in 3D and the decoupled 15 partial PDFs at each stress level reveal quantitatively how the SRO and MRO structures evolve or reconfigure in 3D space in the tensile and compressive stress states. The results show that the Zr-centred atom clusters have low degree of icosahedra and are the preferred atom clusters to rearrange themselves under the tensile and compressive stresses. The Zr-Zr is the dominant atom pair in controlling the shear band's initiation and propagation. The evolution and reconfiguration of the MRO clusters under different stress states are realised by changing the connection modes between the Zr-centred atom clusters. The coordinated changes of both bond angles and bond lengths of the Zr-centred clusters are the dominant factors in accommodating the tensile or compressive strains. While other solute-centred MRO clusters only play minor roles in the atomic structure reconfiguration/evolution. The research has demonstrated a synergetic and multimodal materials operando characterization methodology that has great application potential in design and development of high performance multiple-component engineering alloys. [Display omitted] [ABSTRACT FROM AUTHOR]

Metastable precipitates of solute atoms, known as Guinier–Preston (GP) zones, play a significant role in the age hardening of Al–Cu alloys. In this study, we utilized the classical nucleation theory (CNT) to obtain time-temperature-transformation (TTT) diagrams for steady-state nucleation over a wide temperature range. The CNT model, which is based on atomistic simulations using artificial neural network potentials, was constructed to predict the nucleation kinetics of GP zones in the Al–Cu system with solute concentrations ranging from 1.3 to 2.5 at% (3.0 to 5.7 wt%). The nose temperature at which the steady-state nucleation time for GP zone formation is the shortest was calculated. The nose temperature increased and the minimum nucleation time decreased as the solute concentration increased. These predictions are comparable to previous theoretical results and are in good qualitative agreement with experimental observations. Furthermore, two formation scenarios of double-layer GP (GP2) zones, considering synchronous and asynchronous attachments of solute atoms to clusters, were compared in terms of nucleation efficiency. This provides new insights into the nucleation pathways of the GP2 zone in Al–Cu alloys. [Display omitted] • Classical nucleation theory was applied to predict nucleation times of the GP zone. • This method is based on atomistically informed parameterization. • Time-temperature-transformation diagrams over a wide temperature range were obtained. • The predicted nose temperatures agreed well with the experimental results. • Two formation scenarios of the GP2 zone were compared regarding nucleation efficiency. [ABSTRACT FROM AUTHOR]

We use molecular dynamics to assess the effect of grain boundaries and rigid intergranular inclusions on plastic deformation in nickel (Ni) containing helium (He) bubbles and self-interstitial atom clusters. Our simulations show that plasticity in Ni bicrystals is relatively uniform, with no localized slip bands or nano-twins. We attribute this behavior to grain boundaries, which block dislocations and favor activation of new sources over persistent slip along a single plane. While there is no initiation of intergranular cracks, He bubbles at matrix/inclusion interfaces elongate along the tensile axis and migrate towards regions of high tension, potentially setting the conditions for formation of crack-like flaws via bubble coalescence. We discuss the implications of our work for understanding degradation of mechanical properties in Ni-base alloys in nuclear reactors. [ABSTRACT FROM AUTHOR]

[Display omitted] • The hydrogen storage capacity of Li-decorated Al 12 N 12 clusters is computationally investigated. • The clustering of the Li atoms can be prevented on the nanocage surface. • Each Li atom in the Li-decorated Al 12 N 12 can adsorb a maximum of 3 H 2 molecules with the ideal adsorption energy. • Maximum gravimetric density is achieved to be 11.2 wt%. The hydrogen storage capacity of Li-decorated Al 12 N 12 clusters is investigated using density functional theory computations. The present results indicate that Li atoms are strongly attached on tops of N atoms of the Al 12 N 12 nanocage, forming Al 12 N 12 Li m (m = 1, 2, 4, 8, 12) complexes. The binding energies of the Li atoms on the Al 12 N 12 are in the range of 1.60–1.95 eV, which are larger than that among Li atoms. The clustering of Li atoms can be effectively prevented on the surface of the host. The charge transfer from Li atoms to the Al 12 N 12 makes Li atoms positively charged. Each Li atom in the Li-decorated Al 12 N 12 complexes can adsorb a maximum of 3 H 2 molecules with the average adsorption energy of 0.09–0.12 eV/H 2. The polarization interaction is responsible for the adsorption of H 2 molecules to Li-decorated Al 12 N 12 complexes. The fully coated Al 12 N 12 Li 12 complex can hold up to 36 H 2 molecules, and the corresponding gravimetric density of hydrogen is 11.2 wt%, far exceeding the ultimate target of 6.5 wt% of U. S. DOE. [ABSTRACT FROM AUTHOR]

Atomic Pd x Au y (1 ≤ x + y ≤ 4) clusters are decorated on polyaniline to be used as the catalytic electrode in electrochemical sensors. The current responses in the oxidation of 1-propanol are used to reveal the catalytic activity. Effects of the size, decoration sequence, and composition of the atomic metal clusters decorated on the PANI on the catalytic activity are evaluated. Regarding the size, an odd-even size effect is observed in the atomic pure metal clusters, which the even-numbered pure metal clusters show a higher catalytic activity than the odd-numbered pure metal clusters. For the decoration sequence, the catalytic activity is high when the same metal is decorated in the first two cycles of the cyclic atomic electrodeposition process. For the composition effect, the atomic metal clusters show a high catalytic activity in the oxidation, in the region of second oxidation peak, when there are more Au in the atomic metal clusters. [Display omitted] • Atomic Pd x Au y (1 < x + y < 4) clusters are decorated on PANI toward 1-propanol oxidation. • Atomic pure Pd and Au clusters both show the odd-even effect. • Effects of the decoration sequence and composition are studied. • Decorating the same metal in the first 2 cycles result a better catalytic activity. • Clusters of more Pd show a low catalytic activity in the second oxidation peak. [ABSTRACT FROM AUTHOR]

Fe single-atom catalysts (SACs) have emerged as a promising alternative to platinum for catalyzing oxygen reduction reactions (ORR). Nevertheless, their practical applicability is hindered by insufficient stability caused by structural corrosion during ORR. Here, we developed an effective strategy to optimize and stabilize the Fe SAs (single-atoms) sites by implanting chromium (Cr) atomic clusters (ACs) to address the formidable deactivation issue of the best-performing yet unstable Fe-N-C catalysts. Cr AC -Fe 1 /N-S-C demonstrates an amazing stability with a negligible decline in activity after 100,000 CV cycles, and can maintain 81% of initial current after a continuous 50-hour operation period. Theoretical calculations and experimental evidence substantiate that the integration of Cr ACs not only weakens the binding of OH* to the Fe site, thereby facilitating the ORR process, but also eliminates in situ-generated reactive oxygen species (ROS) and retards Fe ion leaching from active sites, thus stabilizing of the Fe SA sites. [Display omitted] • A novel Cr ACs-modified Fe SAs co-embedded on N, S co-doped carbon matrix is prepared by one-step pyrolysis. • Cr AC sites act proactively to eliminate in situ-generated radicals and show down Fe leaching at the neighboring Fe sites. • The sample exhibits highly stable ORR performance and can be run over 500 hours continuously in a zinc-air battery. [ABSTRACT FROM AUTHOR]

Developing highly sensitive, power-efficient, and recoverable materials are significant for the detection of toxic gases in the environment. Herein, a comprehensive computation of the CH 4 , CO, H 2 S, NH 3 , NO, and NO 2 adsorption performance for the intrinsic and Pd atomic clusters decorated WS 2 (Pd n /WS 2 , n = 1–4) was carried out using density functional theory. The larger adsorption energies and more charge transfer indicate that Pd n /WS 2 species are more sensitive than the intrinsic WS 2. Remarkably, Pd 2 /WS 2 and Pd 3 /WS 2 exhibit distinguished adsorption performance, suggesting that Pd 2 /WS 2 and Pd 3 /WS 2 are the potential ideal candidates for gas sensors. It is also noticed that combined with the moderate adsorption energies, relative high charge transfer, and short recovery time, the Pd 2 /WS 2 and Pd 3 /WS 2 are ideal candidates as CH 4 gas detection with the excellent sensitivity and rapid response in coal mines at room temperature. This finding paves the way to develop high-sensitivity gas sensors, making them suitable for the gas sensing application. [Display omitted] • The effect of Pd atomic clusters decorated WS 2 on structural and electronic properties are discussed in detail. • Pd n /WS 2 species exhibit significantly better sensitivity compared to the pristine WS 2. • The Pd 2 /WS 2 and Pd 3 /WS 2 are ideal candidates as CH 4 gas detection with the excellent sensitivity and rapid response. [ABSTRACT FROM AUTHOR]

The structures of atomic clusters and GP-zones preceding precipitation in an Al-0.70Mg-0.85Si-0.15Fe-0.25Mn (wt. %) alloy have been investigated by annular dark field scanning transmission electron microscopy imaging and density functional theory calculations. One analysed condition consisted of one-month natural aging, and another was in a pre-baked state after 24 h aging at 90 °C. To quantify the effect of clusters and GP-zones on microstructure development during a subsequent isothermal artificial aging at 185 °C, hardness evolution was measured, and precipitate statistics was performed at the peak hardness corresponding to 5 h aging. Several types of clusters and GP-zones have been observed and based on structure and visual appearance named 'Disordered Frank-Kasper', 'Square', 'Binocular', and 1β", 2β", 3β", 4β". The first four are most common in the natural aged condition and are associated with a well-known influence on the initial hardness evolution. The last three are fractions of the hardening β" phase and refer to the number of structural units they contain. These GP-zones have an increased density in the pre-baked condition, leading to a rapid increase in hardness during artificial aging and to a finer microstructure of high-density small needle precipitates at peak hardness. [Display omitted] [ABSTRACT FROM AUTHOR]

In order to reproduce the atomic interaction at the interface between iron (Fe) and iron fluoride (FeF2, FeF3) and liquid sodium atoms, we created a cluster model in which Na atoms were placed on the surface of each material. The electronic states of each cluster model were calculated using the DV-Xα method, one of first-principles calculations. Figure (a) shows the strength of the covalent bonding (BO: Bond Order) between the central Fe atom of each cluster models and liquid Na atoms. Figure (b) shows the strength of the covalent bonding between the central F atom of each cluster models and liquid Na atoms. It is shown that the covalent bonding of FeF2 with Na atom is relatively larger than that of Fe with Na atom. In contrast, the covalent bonding of FeF3 with Na atom was not much different from that of Fe with Na atom. Figure (c) shows the amount of the difference in ionicity transferred from Na atoms to the central atom of each cluster model. The correlation was found between the oxidation number of Fe atoms by F atoms and the amount of difference in ionicity. [Display omitted] Atomic interactions at the interface involving iron, iron fluorides (iron (II) fluoride and iron (III) fluoride), and sodium were investigated using first-principles calculations. The wettability with liquid sodium was subsequently examined, focusing on the calculated atomic interactions. From a covalent bonding perspective, iron (II) fluoride exhibited weaker bonds between neighboring atoms in the substrate material than iron (III) fluoride. However, it exhibited relatively strong bonds between the substrate material and sodium atoms. In contrast, iron (III) fluoride had stronger bonds between neighboring atoms in the substrate material, with weaker bonds between the substrate material and sodium atoms. Additionally, in terms of ionic bonding, the contact of the sodium atom with the substrate material increased the charge transfer of the substrate material atom, correlating with the oxidation number of iron. Iron (III) fluoride exhibited the most substantial charge transfer among the substrate materials. The charge transfer from the sodium atom to the atom in contact with it was approximately 2.5 times that of iron. This result underscores the change in electronic states induced by the iron or iron fluoride interface, potentially influencing the wettability between the material surface and liquid sodium. [ABSTRACT FROM AUTHOR]

[Display omitted] • The MnCl 3 /SbAs system exhibits ferromagnetic ground states, out-of-plane magnetic anisotropy, and half-metallic properties. • The magnetic moment of the system comes from MnCl 3 , and the magnetic anisotropy is mainly contributed by the SbAs substrate. • The ferromagnetic coupling of the MnCl 3 /SbAs system occurs through the p z orbitals of the SbAs substrate. Two-dimensional (2D) magnetic materials with large magnetic anisotropy are crucial for developing thermally stable, miniaturized, and low-power spintronic devices. However, naturally existing 2D materials with intrinsic anisotropic magnetization are scarce. Employing a bottom-up primitive assembly approach and first-principles calculations, we find that the adsorption of MnCl 3 superatoms not only induces magnetism in non-magnetic monolayer SbAs but also hardens it (large out-of-plane magnetic anisotropy). The MnCl 3 /SbAs system becomes a ferromagnetic half-metal with high Curie temperature. Interestingly, the delocalized p orbitals of Sb/As not only mediate the long-range magnetic exchange but also contribute to the significant magnetic anisotropic energy. The magnetic exchange and anisotropy of the system can be efficiently modulated by changing the assembly mode of MnCl 3 on the SbAs surface. This study presents an alternative concept and method for the development of 2D ferromagnetic materials with uniaxial magnetic anisotropy, which holds promise for spintronic device applications. [ABSTRACT FROM AUTHOR]