Exploring high-performance zeolite-supported metal catalysts is of great significance. Herein, we develop a strategy for fabricating isolated single metal atomic site catalysts in Y zeolite (M-ISAS@Y, M = Pt, Pd, Ru, Rh, Co, Ni, Cu) by in situ separating and confining a metal−ethanediamine complex into β-cages during the crystallization process followed by thermal treatment. The M-ISAS are stabilized by skeletal oxygens of Y zeolite, and the crystallinity, porosity, and large surface area are well inherited in M-ISAS@ Y. As a demonstration, acidic Pt-ISAS@Y is used for n-hexane isomerization involving consecutive catalytic dehydrogenation/hydrogenation on Pt-ISAS and isomerization on Brønsted acid sites. The turnover frequency value of Pt-ISAS reaches 727 h −1 , 5 times more than Pt nanoparticles (∼3.5 nm), with a total isomer selectivity of more than 98%. This strategy provides a convenient route to fabricate promising zeolite-based M-ISAS catalysts for industrial applications.

The properties of two-dimensional assemblies of metal nanoparticles are controlled by the composition, geometry, and spatial arrangement of the nanoparticle building blocks. Such structures have been used for a variety of important applications in catalysis, photonics, electronics, and biological sensing. [1][2][3][4][5][6][7] Although the bulk of such work has focused on assemblies of spherical or pseudo-spherical structures, [8][9][10][11] anisotropic metal nanomaterials are also an in-

Single-atom catalysts are of great interest because they can maximize the atom-utilization efficiency and generate unique catalytic properties; however, much attention has been paid to single-site active components, rarely to catalyst promoters. Promoters can significantly affect the activity and selectivity of a catalyst, even at their low concentrations in catalysts. In this work, we designed and synthesized CuO catalysts with atomically dispersed co-promoters of Sn and Zn. When used as the catalyst in the Rochow reaction for the synthesis of dimethyldichlorosilane, this catalyst exhibited much-enhanced activity, selectivity and stability compared with the conventional CuO catalysts with promoters in the form of nanoparticles. Density functional theory calculations demonstrate that single-atomic Sn substitution in the CuO surface can enrich surface Cu vacancies and promote dispersion of Zn to its atomic levels. Sn and Zn single sites as the co-promoters cooperatively generate electronic interaction with the CuO support, which further facilitates the adsorption of the reactant molecules on the surface, thereby leading to the superior catalytic performance.

Reliability in molecular electronics break-junction experiments has come from statistically sampling thousands of repeat measurements. Here we discuss the computational challenges in reproducing the experimental conductance histograms and introduce a computational strategy to model molecular electronics experiments with statistics. The strategy combines classical molecular dynamics (MD) of junction formation and evolution, using a reactive force field that allows for bond-breaking and -making processes, with steady-state electronic transport computations using Green’s function methods in the zero-bias limit. The strategy is illustrated using a molecular junction setup where an octanedimethylsulfide (C8SMe) connects to two gold electrodes. To attempt to reproduce the statistics encountered in experiments, we performed simulations using (1) a single MD trajectory of junction formation and evolution; (2) several MD trajectories with identical initial geometry for the electrodes; and (3) several MD trajectories each with a different geometry for the electrodes (obtained by separately crushing the electrodes and breaking the gold–gold contact). We find that these three classes of simulations can exhibit an apparent agreement with the experimental conductance histograms. Nevertheless, these simulations miss the time-averaging of the current that is inherent to the experiment. We further examined the simulated time-averaged currents for an ensemble of trajectories with crushed electrodes and found that such simulations recover the width of the experimental conductance histograms despite the additional averaging. These results highlight the challenges in connecting theory with experiment in molecular electronics and establish a hierarchy of methods that can be used to understand the factors that influence the experimental conductance histogram.

The simple ABO3 and A-site-ordered AA′3B4O12 perovskites represent two types of classical perovskite functional materials. There are well-known simple perovskites with ferroelectric properties, while there is still no report of ferroelectricity due to symmetry breaking transition in A-site-ordered quadruple perovskites. Here we report the high pressure synthesis of an A-site-ordered perovskite PbHg3Ti4O12, the only known quadruple perovskite that transforms from high-temperature centrosymmetric paraelectric phase to low-temperature non-centrosymmetric ferroelectric phase. The coordination chemistry of Hg2+ is changed from square planar as in typical A-site-ordered quadruple perovskite to a rare stereo type with 8 ligands in PbHg3Ti4O12. Thus PbHg3Ti4O12 appears to be a combinatory link from simple ABO3 perovskites to A-site-ordered AA′3Ti4O12 perovskites, sharing both displacive ferroelectricity with former and structure coordination with latter. This is the only example so far showing ferroelectricity due to symmetry breaking phase transition in AA′3B4O12-type A-site-ordered perovskites, and opens a direction to search for ferroelectric materials.