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  1. Abstract Image Advances in the synthesis and self-assembly of nanocrystals have enabled researchers to create a plethora of different nanoparticle superlattices. But while many superlattices with complex types of translational order have been realized, rotational order of nanoparticle building blocks within the lattice is more difficult to achieve. Self-assembled superstructures with atomically coherent nanocrystal lattices, which are desirable due to their exceptional electronic and optical properties, have been fabricated only for a few selected systems. Here, we combine experiments with molecular dynamics (MD) simulations to study the self-assembly of heterostructural nanocrystals (HNCs), consisting of a near-spherical quantum dot (QD) host decorated with a small number of epitaxially grown gold nanocrystal (Au NC) “patches”. Self-assembly of these HNCs results in face-centered-cubic (fcc) superlattices with well-defined orientational relationships between the atomic lattices of both QD hosts and Au patches. MD simulations indicate that the observed dual atomic coherence is linked to the number, size, and relative positions of gold patches. This study provides a strategy for the design and fabrication of NC superlattices with large structural complexity and delicate orientational order. 
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  2. Abstract

    Direct synthesis of CH3COOH from CH4and CO2is an appealing approach for the utilization of two potent greenhouse gases that are notoriously difficult to activate. In thisCommunication, we report an integrated route to enable this reaction. Recognizing the thermodynamic stability of CO2, our strategy sought to first activate CO2to produce CO (through electrochemical CO2reduction) and O2(through water oxidation), followed by oxidative CH4carbonylation catalyzed by Rh single atom catalysts supported on zeolite. The net result was CH4carboxylation with 100 % atom economy. CH3COOH was obtained at a high selectivity (>80 %) and good yield (ca. 3.2 mmol g−1catin 3 h). Isotope labelling experiments confirmed that CH3COOH is produced through the coupling of CH4and CO2. This work represents the first successful integration of CO/O2production with oxidative carbonylation reaction. The result is expected to inspire more carboxylation reactions utilizing preactivated CO2that take advantage of both products from the reduction and oxidation processes, thus achieving high atom efficiency in the synthesis.

     
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  3. Abstract

    Direct synthesis of CH3COOH from CH4and CO2is an appealing approach for the utilization of two potent greenhouse gases that are notoriously difficult to activate. In thisCommunication, we report an integrated route to enable this reaction. Recognizing the thermodynamic stability of CO2, our strategy sought to first activate CO2to produce CO (through electrochemical CO2reduction) and O2(through water oxidation), followed by oxidative CH4carbonylation catalyzed by Rh single atom catalysts supported on zeolite. The net result was CH4carboxylation with 100 % atom economy. CH3COOH was obtained at a high selectivity (>80 %) and good yield (ca. 3.2 mmol g−1catin 3 h). Isotope labelling experiments confirmed that CH3COOH is produced through the coupling of CH4and CO2. This work represents the first successful integration of CO/O2production with oxidative carbonylation reaction. The result is expected to inspire more carboxylation reactions utilizing preactivated CO2that take advantage of both products from the reduction and oxidation processes, thus achieving high atom efficiency in the synthesis.

     
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