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Highly ordered hierarchical TiO2 nanotube (HTNT) arrays are obtained with a facile and low-cost approach, which can be applied in flexible fiber-type dye-sensitized solar cells (DSSCs). To achieve the HTNT arrays, smooth TiO2 nanotube (STNT) arrays are fabricated by a two-step anodization process followed by hydrothermal treatment in the presence of the aqueous solution of NH4F. Both STNT and HTNT arrays can serve as photoanodes in the flexible fiber-type DSSCs. We demonstrate that the conversion efficiency of the HTNT array-based flexible fiber-type DSSC (8.6%), which has increased by more than 30% compared with that of the STNT array-based flexible fiber-type DSSC. Moreover, the conversion efficiency is highly stable, even when the flexible fiber-type DSSC is subjected to extreme mechanical deformation, such as 180° bending. This promising conversion efficiency may originate from the significant dye loading capability of the photoanode, which has an enormous surface area benefited from the hierarchical nanostructures. [ABSTRACT FROM AUTHOR]

Toughening ceramics has been a long‐standing challenge. By chemically infiltrating B4C into aligned carbon nanotubes (CNTs) sheets, we fabricate a novel CNT/B4C composite with a fracture strength approaching the theoretical maximum of B4C matrix. The CNT/B4C composites simultaneously possess a strongly bonded tube/matrix interface and an amorphous, crack‐free B4C matrix. The fracture strength of the CNT/B4C nanowires is about 1–2 orders of magnitude higher than that of the bulk B4C. [ABSTRACT FROM AUTHOR]

Abstract: Robust Gd–La codoped TiO2 microspheres with diameter of 2∼3 μm were successfully synthesized via a hydrothermal method using poly(ethylene glycol)-block–poly(propylene glycol)-block–poly(ethylene glycol) as a template. The photocatalytic activity of the Gd–La codoped TiO2 microspheres evaluated by photodegrading methyl orange (MO) has been significantly enhanced compared to that of undoped TiO2 microspheres. Ti4+ may substitute for La3+ and Gd3+ in the lattices of rare earth oxides to create abundant oxygen vacancies and surface defects for electron trapping and dye adsorption, accelerating the separation of photogenerated electron–hole pairs and MO photodegradation. The formation of an exciton energy level below the conduction band of TiO2 from the binding of electrons and oxygen vacancies decreases the excitation energy of Gd–La codoped TiO2 microspheres, resulting in robust photocatalysts. The results suggest that Gd–La codoped TiO2 microspheres calcined at 350 °C are very promising for enhancing the photocatalytic activity of photocatalysts. [Copyright &y& Elsevier]

Activated carbon (AC)-based materials have shown promising performance in carbon capture, offering low cost and sustainable sourcing from abundant natural resources. Despite ACs growing as a new class of materials, theoretical guidelines for evaluating their viability in carbon capture are a crucial research gap. We address this gap by developing a hierarchical guideline, based on fundamental gas-solid interaction strength, that underpins the success and scalability of AC-based materials. The most critical performance indicator is the CO 2 adsorption energy, where an optimal range (-0.41 eV) ensures efficiency between adsorption and desorption. Additionally, we consider thermal stability and defect sensitivity to ensure consistent performance under varying conditions. Further, selectivity and capacity play significant roles due to external variables such as partial pressure of CO 2 and other ambient air gases (N 2 , H 2 O, O 2 ), bridging the gap between theory and reality. We provide actionable examples by narrowing our options to methylamine- and pyridine-grafted graphene.

Rationale: de Winter electrocardiograph (ECG) pattern signifies proximal left anterior descending coronary artery (LAD) occlusion and extensive anterior myocardial infarction, and it is found in about 2% of patients with proximal LAD occlusion. However, it is often unrecognized by physicians. In this case report, we present a patient with chest pain but showing an atypical and delayed de Winter ECG pattern., Patient Concerns: A previously healthy 61-year-old man attended our emergency department with chest pain radiating to the left arm and back for 4 hours, who was without serious cardiovascular risk factors. ECG at emergency department showed no significant changes. High-sensitivity cardiac troponin I (hs-cTnI) was within normal limit., Diagnosis: At 5 hours after onset, ECG showed significant upsloping ST depression at J point in precordial leads V3 to V6, slight ST elevation in aVR and depression in inferior leads, and hs-cTnI peaked at 2.610 μg/L. The diagnosis of de Winter ECG pattern was confirmed by coronary angiography with an occlusion of the proximal LAD., Interventions: A stent was implanted through percutaneous coronary intervention., Outcomes: The patient's chest pain was relieved without further increase of hs-cTnI. ECG after procedure showed ST segment back to baseline in leads V4 to V6, but persistent ST elevation in V1 to V3 with QS or Q wave., Lessons: Timely diagnosis of de Winter ECG pattern is very important, especially the atypical and delayed ECG changes. It should be treated as ST elevation myocardial infarction equivalent and deserves emergent revascularization therapy.

There is a longstanding challenge to disperse metal nanoparticles uniformly in bulk polymers for widespread applications. Conventional scale-down techniques often are only able to shrink larger elements (such as microparticles and microfibers) into micro/nano-elements (i.e. nanoparticles and nanofibers) without much altering their relative spatial and size distributions. Here we show an unusual phenomenon that tin (Sn) microparticles with both poor size distribution and spatial dispersion were stretched into uniformly dispersed and sized Sn nanoparticles in polyethersulfone (PES) through a stack and draw technique in thermal drawing. It is believed that the capillary instability plays a crucial role during thermal drawing. This novel, inexpensive, and scalable method overcomes the longstanding challenge to produce bulk polymer-metal nanocomposites (PMNCs) with a uniform dispersion of metallic nano-elements.

An in situ quantitative tensile testing platform is developed to enable the uniform in-plane loading of a freestanding membrane of 2D materials inside a scanning electron microscope. The in situ tensile testing reveals the brittle fracture of large-area MoSe 2 crystals and measures their fracture strength for the first time., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Structural defects in monolayer molybdenum disulfide (MoS2) have significant influence on the electric, optical, thermal, chemical, and mechanical properties of the material. Among all the types of structural defects of the chemical vapor phase-grown monolayer MoS2, the VMoS3 point defect (a vacancy complex of Mo and three nearby S atoms) is another type of defect preferentially generated by the extended electron irradiation. Here, using the classical molecular dynamics simulation with reactive empirical bond-order (REBO) potential, we first investigate the effect of VMoS3 point defects on the elastic properties of monolayer MoS2 sheets. Under the constrained uniaxial tensile test, the elastic properties of monolayer MoS2 sheets containing VMoS3 vacancies with defect fraction varying from 0.01 to 0.1 are obtained based on the plane anisotropic constitutive relations of the material. It is found that the increase of VMoS3 vacancy concentration leads to the noticeable decrease in the elastic modulus but has a slight effect on Poisson's ratio. The maximum decrease of the elastic modulus is up to 25 %. Increasing the ambient temperature from 10 K to 500 K has trivial influences on the elastic modulus and Poisson's ratio for the monolayer MoS2 without defect and with 5 % VMoS3 vacancies. However, an anomalous parabolic relationship between the elastic modulus and the temperature is found in the monolayer MoS2 containing 0.1 % VMoS3 vacancy, bringing a crucial and fundamental issue to the application of monolayer MoS2 with defects.

Two-dimensional (2D) layered semiconducting transition-metal dichalcogenides (TMDCs) are promising candidates for next-generation ultrathin, flexible, and transparent electronics. Chemical vapor deposition (CVD) is a promising method for their controllable, scalable synthesis but the growth mechanism is poorly understood. Herein, we present systematic studies to understand the CVD growth mechanism of monolayer MoSe2 , showing reaction pathways for growth from solid and vapor precursors. Examination of metastable nanoparticles deposited on the substrate during growth shows intermediate growth stages and conversion of non-stoichiometric nanoparticles into stoichiometric 2D MoSe2 monolayers. The growth steps involve the evaporation and reduction of MoO3 solid precursors to sub-oxides and stepwise reactions with Se vapor to finally form MoSe2 . The experimental results and proposed model were corroborated by ab initio Car-Parrinello molecular dynamics studies., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The practical recycling of carbon dioxide (CO2) by the electrochemical reduction route requires an active, stable, and affordable catalyst system. Although noble metals such as gold and silver have been demonstrated to reduce CO2 into carbon monoxide (CO) efficiently, they suffer from poor durability and scarcity. Here we report three-dimensional (3D) graphene foam incorporated with nitrogen defects as a metal-free catalyst for CO2 reduction. The nitrogen-doped 3D graphene foam requires negligible onset overpotential (-0.19 V) for CO formation, and it exhibits superior activity over Au and Ag, achieving similar maximum Faradaic efficiency for CO production (∼85%) at a lower overpotential (-0.47 V) and better stability for at least 5 h. The dependence of catalytic activity on N-defect structures is unraveled by systematic experimental investigations. Indeed, the density functional theory calculations confirm pyridinic N as the most active site for CO2 reduction, consistent with experimental results.