Vapor phase infiltration (VPI) derived from atomic layer deposition (ALD) enables inorganic materials to nucleate and grow within the free volume of polymers, which has shown promising prospects in the field of composite solid polymer electrolytes (CSPEs). However, there are only a few types of metal oxides that can be incorporated into the polymer matrix by VPI, let alone binary metal oxides, due to the limited knowledge of the VPI synthesis process. To combine the merits of different metal oxides, we investigate the VPI method to prepare ZnO-Al2O3 composites in poly(ethylene oxide) (PEO). When the introducing order is Al2O3/ZnO (AZO), due to the extremely high reactivity of trimethyl aluminum (TMA) with PEO, VPI-Al2O3 will accumulate near the surface of PEO. The surface Al2O3 layer inhibits the further diffusion of the diethyl zinc (DEZ) into the PEO matrix, leading to weak polymer-filler interactions and limited improvement of the Li+ conduction. In the incorporation order of ZnO/Al2O3 (ZAO), the moderate reactivity of DEZ renders the uniform distribution of VPI-ZnO within PEO, and the following TMA can both react with PEO and VPI-ZnO particles near the surface of PEO, which not only preserves the interactions between VPI-ZnO and PEO but also better inhibits the growth of lithium dendrites. The incorporation order plays a crucial role in the morphology and composition of binary metal oxides synthesized by VPI.

Mixed-metal metal-organic frameworks (MM-MOFs) contain more than one type of metal node, which can improve or even introduce new features compared with the single metal frameworks. Traditionally, most of the MM-MOFs are synthesized by solution method which requires all the metal ions to form stable coordination with the ligand in a single framework and therefore limits the choice of the metal ions. In this work, Pt-doped Zn-MOF-74 (PtZn-MOF-74) has been prepared through a mechanochemical conversion approach from Pt-doped ZnO (Pt–ZnO) directly. The absence of a large quantity of solvent limits the solvation and diffusion of growth species during the mechanochemical conversion and therefore prevented the agglomeration of Pt dopants in PtZn-MOF-74. CO oxidation was used to evaluate the catalytic performance of the prepared MM-MOFs. Compared with inert Zn-MOF-74, PtZn-MOF-74 with unsaturated coordinated Pt at elevated temperature can act as the active sites to catalyze CO oxidation reaction. This study provides a novel design strategy for the synthesis of MM-MOFs with extended functionalities.

Bottom-up synthesis based on site-selective atomic layer deposition is a powerful atomic-scale processing approach to fabricate materials with desired functionalities. Typical selective atomic layer deposition (ALD) can be achieved using selective activation of a growth area or selective deactivation of a protected area. In this work, we explored the site selectivity based on the difference of the inherent surface reactivity between different materials and within the same materials. By sequentially applying two site-selective atomic layer deposition, the ALD Pd catalyst is spatially confined on ALD SnO2 modified h-BN substrate Pd/SnO2/h-BN shows improved catalytic activity and stability due to strong metal-support interactions and spatial confinement. The results reveal that sequential site-selective ALD is a feasible and effective synthesis strategy that provides an attractive path toward designing and developing highly stable catalysts.

Solid-state lithium-metal batteries with composite polymer electrolytes are promising for next-generation energy-storage devices. Typical synthesis strategies of preparing inorganic-polymer composite mainly focused on physical mixing of inorganic fillers with polymer or surface coating of inorganic thin films on polymer, which are hard to suppress Li-dendrite penetration. Here, we demonstrate the bulk and interface properties of powdery poly (ethylene oxide) can be modified simultaneously with highly dispersed alumina using a vapor phase infiltration (VPI) approach. The chemically synthesized alumina with under-coordinated aluminum sites shows strong interaction with PEO, and therefore highly dispersed in the polymer matrix as well as on the surface of the polymer. On the lithium metal anode side, it reduces the interfacial resistance and allows Li vertical bar Li symmetric battery to cycle more than 1400 h under 0.2 mAh/cm(2). On the cathode side, it increases the electrochemical stability window of PEO up to 4.25V without compromising the charge transfer kinetics. The result shows the promise of using VPI as a facile one-step method to tune the properties of the polymer on a large scale for battery applications. (C) 2022 Elsevier Ltd. All rights reserved.

The acquisition of monodisperse metal nanoparticles covered by conductive metal-organic frameworks (cMOFs) is an archetype of an electron-unobstructed core-shell composite, valued for its potential electrocatalytic ability and selectivity enhancement. In this work, Pt@cMOF composites with direct interfaces showed better performance in the oxygen reduction reaction than composites with indirect interfaces or with lower electroconductivity shells. This composite was proved to exhibit the ability to expedite electron transfer with different thicknesses of electrode materials. The detailed mechanism was studied by exploring the conductivity of shell materials, interfaces between cores and shells, and the surface electronic structure of the nanoparticles. We also report reaction selectivity from the inherent porous shells in the selective reduction of cinnamyl alcohol.

Metal-organic frameworks (MOFs), a new type of porous material, have shown many possible applications in gas storage and separation, biomedicine, catalysis, and so on. While most MOFs are synthesized through solvothermal synthesis where a large quantity of organic solvent is used, the green synthetic approach using a minimized amount of solvent is important to prevent irreversible environmental compacts. In this study, we successfully synthesized Zr-MOFs with SBUs (e.g., UiO-66 and MIL-140A) using a simple metal source and investigated the role of organic modulators in modulating the MOF structures during solid-state synthesis. Meanwhile, UiO-66 rich in defects synthesized via a solid-state conversion strategy shows good catalytic performance for the ring-opening of epoxides with alcohols. This work contributes to the understanding of the role of organic modulators in the solid-state synthesis of MOFs.

Thin films with effective ion sieving ability are highly desired in energy storage and conversion devices, including batteries and fuel cells. However, it remains challenging to design and fabricate cost-effective and easy-to-process ultrathin films for this purpose. Here, we report a 300 nm-thick functional layer based on porous organic cages (POCs), a new class of porous molecular materials, for fast and selective ion transport. This solution processable material allows for the design of thin films with controllable thickness and tunable porosity by tailoring cage chemistry for selective ion separation. In the prototype, the functional layer assembled by CC3 can selectively sieve Li+ ions and efficiently suppress undesired polysulfides with minimal sacrifice for the system's total energy density. Separators modified with POC thin films enable batteries with good cycle performance and rate capability and offer an attractive path toward the development of future high-energy-density energy storage devices.

Perfect crystals do not exist; however, the introduction of defects can tailor the physical and chemical properties of materials. Defects in metal-organic frameworks (MOFs) have been demonstrated to be important in many applications, including but not limited to catalysis, gas separation, and energy storage. While a few liquid-phase synthesis methods have been reported to prepare defect-rich UiO-66, the heavy use of organic solvents may cause irreversible environmental problems. Here, we present a green, rapid, and facile solid-state synthesis approach to prepare UiO-66. All UiO-66 crystals remain in the nanometer size due to the limited diffusivity of growth species in solid-state synthesis without a large quantity of the solvent. The defect concentrations can be fine-tuned by the content of ethanol addition. Defect-rich UiO-66 shows excellent catalytic activity to the ring opening of epoxides with alcohols. This work provides insights into the large-scale production of defect-rich MOFs.

We propose a novel strategy to introduce platinum into the metal nodes of ZIF-8 by preloading Pt as a dopant in ZnO (Pt-ZnO) and then convert it to Pt doped ZIF-8 (Pt-ZIF-8) through a chemical vapor deposition (CVD) approach. The solvent-free conversion of Pt-ZnO to Pt-ZIF-8 allows the Pt dopant in ZnO to coordinate with organic linkers directly without the formation of Pt nanoparticles, which is a general issue of many methods. This general synthesis strategy may facilitate the discovery of MMOFs that have not been reported previously.

The porous 2D metal-organic frameworks (MOFs) possess 1D channels derived from the stacking sequence of the 2D layers. The nanoparticles (NPs)@2D MOFs core-shell structures are potential composites catalysts in exposing more accessible active sites via 1D channels, in addition to enriching the reactants in the porous structure as normal MOFs. Here we present a novel and universal strategy for embedding pre-synthesized metal NPs into the 2D MOFs, forming a fully encapsulated compact core-shell structure. The method has proven to be versatile not only for embedding NPs with different metals and morphologies but also for 2D MOFs with different nodes and linkers. Various characterization methods, including powder X-ray diffraction, transmission electron microscopy, Raman spectroscopy, etc. have been used to elaborate the mechanism of this encapsulation process, through which an attractive and promising 'clean' interface can be obtained.

Composite solid polymer electrolytes (CSPEs) have long been considered as one of the most promising candidates for all-solid-state lithium batteries owing to the merits of easy fabrication and low cost. However, the inorganic fillers physically mixed into the polymer matrix have weak polymer-filler interactions and tend to agglomerate, which limits the further improvement of the ionic conductivity and Li+ transference number of CSPEs. In this work, we demonstrated ZnO quantum dots can be chemically incorporated into the poly(ethylene oxide) (PEO) matrix by vapor phase infiltration (VPI), a special variant of atomic layer deposition (ALD). The ZnO quantum dots have strong chemical interactions with PEO polymer chains, which suppresses the crystallization of PEO and enhances the Li+ conduction. Due to the strong interactions, ZnO quantum dots distribute uniformly in the PEO-based solid electrolyte matrix as well as the top surface, which leads to a significant decrease of interfacial resistance with Li metal. As a result, the NCM811 vertical bar Li half-cell with the VPI-ZnO/PEO/LiTFSI CSPE exhibit high discharge capacity at 50 degrees C (164.7 mAh g(-1) at 0.5 C (1 C = 200 mA g(-1)), 2.8-4.25 V). This result could potentially serve as a model for a more general approach of using VPI to introduce strong polymer-filler interaction in CSPEs for high-performance lithium metal batteries.