Three-Dimensional Hierarchical Copper-Based Nanostructures as Advanced Electrocatalysts for CO₂ Reduction

Cu-based nanomaterials have received increasing interest for electrocatalytic applications in the CO₂ reduction reaction. However, it is challenging to design nanostructured Cu electrodes to improve both the chemical kinetics and molecular transport under the reaction conditions. Here we report on a new type of three-dimensional Cu-based nanostructures as advanced electrocatalysts for CO₂ reduction. Driven by thermal oxidation, CuO nanowires and/or porous nanostructures are grown on commercial Cu foams with three-dimensional (3D) frameworks. An electrochemical method is used to reduce CuO to Cu with the structural features largely preserved. The derived Cu-based hierarchical nanostructures demonstrate high catalytic activity and selectivity for CO₂ reduction, achieving >80% Faradaic efficiency and ∼3 times enhancement in terms of CO₂ conversion rate as compared to the Cu nanowires grown on planar electrodes. Our work highlights the great potential of 3D Cu nanostructures for improving the energy efficiency and power performance of CO₂ electrolysis

The <i>myotrophin</i> rs17168525 C/T variant occurs in the let-7/miR-98 binding site.

<p>The variant rs17168525 is a C to T change (mRNA sequence as reference) located in the predicted binding site for let-7/miR-98 in the 3′-UTR of the <i>myotrophin</i> gene. C-allele at rs17168525 base-paired with G in Watson—Crick mode (shown with a solid line). However, when the T-allele is present, base-pairing complementarity is interrupted (shown with a dashed line).</p

Baseline characteristics in controls and hypertensive patients.

<p>Values are means ±SD or percentage.</p><p>*P <0.05 and</p><p>**P <0.01 compared with controls.</p><p>BMI, body mass index; BP, blood pressure; SBP, systolic BP; DBP, diastolic BP; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; TC, total cholesterol; TG, triacylglycerol.</p><p>Baseline characteristics in controls and hypertensive patients.</p

The <i>myotrophin</i> rs17168525 C/T variant occurs in the let-7/miR-98 binding site.

<p>The variant rs17168525 is a C to T change (mRNA sequence as reference) located in the predicted binding site for let-7/miR-98 in the 3′-UTR of the <i>myotrophin</i> gene. C-allele at rs17168525 base-paired with G in Watson—Crick mode (shown with a solid line). However, when the T-allele is present, base-pairing complementarity is interrupted (shown with a dashed line).</p

Let-7c suppresses the protein expression level of myotrophin <i>in vitro</i> cellular model.

<p>Cardiomyocytes were infected with PremiR miRNA precursor or Anti-miR miRNA inhibitor of let-7c (<i>A</i> and <i>B</i>). Myotrophin expression was analyzed by immunoblot 48 h after infection. *p < 0.05.</p

Testing the interaction between let-7c and <i>myotrophin</i> using a lucisferase reporter assay.

<p>Hela cells were co-transfected with <i>myotrophin</i>-pMIR-C or <i>myotrophin</i>-pMIR-T, and either negative control miRNA (PremiR-NC) or let-7c. 48 h after transfection, luciferase activities were measured. Firefly luciferase activity was normalized to <i>Renilla</i> luciferase expression, and mean activities ± S.E. from four independent experiments are shown. For <i>myotrophin</i>-pMIR-C transfection, PremiR-NC versus let-7c, P = 0.002; for <i>myotrophin</i>-pMIR-T transfection, PremiR-NC versus let-7c, P = 0.626.</p

Possible associations between <i>myotrophin</i> variant and hypertension or left ventricular hypertrophy in the case-control study.

<p>^a:Compared to controls. Adjusted ORs (95% CIs) were stratified by age, gender, BMI, SBP, DBP, smoking status, alcohol consumption and glucose.</p><p>Possible associations between <i>myotrophin</i> variant and hypertension or left ventricular hypertrophy in the case-control study.</p

An Obtuse Rhombohedral Superlattice Assembled by Pt Nanocubes

We grew large single three-dimensional supercrystals from colloidal Pt nanocubes (NCs) suspended in hexane. A synchrotron-based two circle diffractometer was used to obtain an unprecedented level of detail from full sets of small/wide-angle X-ray scattering (SAXS/WAXS) patterns. Automatic indexing and simulations of X-ray patterns enabled detailed reconstruction of NC translation and shape orientation within the supercrystals from atomic to mesometric levels. The supercrystal has an obtuse rhombohedral (Rh) superlattice with space group <i>R</i>3<i>m</i> and a trigonal cell angle of 106.2°. Individual NCs orient themselves in a manner of atomic Pt[111] parallel to superlattice Rh[111]. We analyzed the superlattice structure in context of three spatial relationships of proximate NCs including face-to-face, edge-to-edge, and corner-to-corner configurations. Detailed analysis of supercrystal structure reveals nearly direct corner-to-corner contacts and a tight interlocking NC structure. We employed the correlations between strain and lattice distortion and established the first structural correlating mechanism between five superlattice polymorphs to elucidate the superlattice transformations and associated developing pathways. Together, the experimental and modeling results provide comprehensive structural information toward controlling design and efficient materials-processing for large fabrication of nanobased functional materials with tailored structures and desired properties

Tilted Face-Centered-Cubic Supercrystals of PbS Nanocubes

We demonstrate a direct fabrication of PbS nanocube supercrystals without size-selection pretreatment on the building blocks. Electron microscopic and synchrotron small angle X-ray scattering analyses confirm that nanocubes pack through a tilted face-centered-cubic (<i>fcc</i>) arrangement, that is, face-to-face along the ⟨110⟩_super direction, resulting in a real packing efficiency of as high as ∼83%. This new type of superstructure consisting of nanocubes as building blocks, reported here for the first time, is considered the most stable surfactant-capped nanocube superstructure determined by far