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Platinum diselenide (PtSe2) is a group-10 two-dimensional (2D) transition metal dichalcogenide that exhibits the most prominent atomic-layer-dependent electronic behavior of "semiconductor-to-semimetal" transition when going from monolayer to bulk form. This work demonstrates an efficient photoelectrochemical (PEC) conversion for direct solar-to-hydrogen (H2) production based on 2D layered PtSe2/Si heterojunction photocathodes. By systematically controlling the number of atomic layers of wafer-scale 2D PtSe2 films through chemical vapor deposition (CVD), the interfacial band alignments at the 2D layered PtSe2/Si heterojunctions can be appropriately engineered. The 2D PtSe2/p-Si heterojunction photocathode consisting of a PtSe2 thin film with a thickness of 2.2 nm (or 3 atomic layers) exhibits the optimized band alignment and delivers the best PEC performance for hydrogen production with a photocurrent density of -32.4 mA cm-2 at 0 V and an onset potential of 1 mA cm-2 at 0.29 V versus a reversible hydrogen electrode (RHE) after post-treatment. The wafer-scale atomic-layer controlled band engineering of 2D PtSe2 thin-film catalysts integrated with the Si light absorber provides an effective way in the renewable energy application for direct solar-to-hydrogen production.

There have been several studies on the catalytic activity of the hydrogen evolution reaction (HER) using ultralow loading of Pt catalysts or even Pt single atom catalysts. However, Pt single atom deposited on the surface of the carbon or metal oxide material has some drawbacks, such as high possibility of Pt desorption from the supported material in the electrolyte. Besides, from the reaction mechanism perspective, each Pt atom in this type of catalyst is too far to achieve high HER efficiency via the Tafel reaction pathway. In this work, gold nanodendrites (Au NDs) with high facet surface were chosen as the supported materials for studying the relation between the low loading amount of Pt atoms and the reaction mechanism of the HER activity. The atomic deposition of Pt atoms on the surface of Au NDs can be controlled effectively using a constant-current synthetic method. It was found that the HER electrocatalytic activity of ultralow Pt loading catalyst, with Pt atoms to total surface atoms of Au NDs (O-Pt on Au NDs) of 5.5%, could achieve high efficiency via the Tafel reaction pathway, showing a low overpotential of ∼18 mV at a current density of 10 mA cm−2 and a small Tafel slope of ∼31 mV dec−1, which is close to that of commercial Pt/C with 20 wt% Pt. As confirmed by Inductively Coupled Plasma Mass Spectrometry(ICP-MS), the Pt loading amount of O-Pt on Au NDs was ∼3.8 ± 0.2 μg cm−2 on a physical area of carbon fiber paper. The turnover frequency (TOF) of O-Pt on Au NDs was found to be 40.1 ± 2.5 H2 per s at 50 mV. This work provides a feasible approach to control the atomic deposition of Pt on a specific substrate as an active catalyst for various catalytic applications.

Using MoS2 nanosheets or composites of MoS2 nanosheets for the anode materials is beneficial to the energy storage performance of lithium ion batteries (LIBs). In order to understand the stability ...

Perovskite α-CsPbI3 nanocrystals (NCs) with a high fluorescence quantum yield (QY) typically undergo a rapid phase transformation to a low QY δ-CsPbI3 phase, thus limiting their optoelectronic appl...

In contrast to the 2D organic-inorganic hybrid Ruddlesden-Popper halide perovskites (RPP), a new class of 2D all inorganic RPP (IRPP) has been recently proposed by substituting the organic spacers with an optimal inorganic alternative of cesium cations (Cs

Hydrogen evolution reaction (HER) from electrocatalytic water splitting is a prospective technology to supply clean energy with low environmental impact for the future. In this work, plasmonic silv...

The aim of this study was to evaluate the effect of the miR-301a/PTEN pathway in cervical cancer. miR-301a and PTEN expression were measured by quantitative real-time PCR (qRT-PCR) in tissues samples and HeLa cells. PTEN protein level was determined by Western blotting. Dual reporter luciferase assay was performed to validate PTEN as a direct target of miR-301a. The gain- and loss-of function assay was performed by miR-301a overexpression and silencing. Cell proliferation was monitored by cell counting Kit-8 (CCK-8). Cell apoptosis was quantitated by flow cytometry. SPSS was used to analyze the significant difference in the treatments. miR-301a demonstrated a significantly higher expression in cervical carcinoma tissues compared with the paired non-carcinoma tissues ( n = 12), while PTEN expression was found to be significantly lower in cervical carcinoma tissues than their paired non-carcinoma tissues ( n = 12). In addition, PTEN was identified as the direct target of miR-301a. Moreover, overexpression of miR-301a significantly promoted HeLa cells proliferation and anti-apoptosis which had a reverse pattern after PTEN overexpression. Our results confirm PTEN as a direct target of miR-301a in HeLa cells and suggest that miR-301a/PTEN pathway contributes to the development and progression of cervical cancer.

Using the focused ion beam (FIB) to prepare plan-view transmission electron microscopy (TEM) specimens is beneficial for obtaining structural information of two-dimensional atomic layer materials, such as graphene and molybdenum disulfide (MoS2) nanosheets supported on substrates. The scanning electron microscopy (SEM) image in a dual-beam FIB-SEM can accurately locate an area of interest for specimen preparation. Besides, FIB specimen preparation avoids damages and hydrocarbon contamination that are usually produced in other preparation methods, in which chemical etching and polymer adhesion layers are used. In order to reduce harmful ion-beam bombardment and re-deposition on the thin atomic layers during FIB specimen preparation, we develop a method to protect the atomic layers by making a “microcapsule” to insulate the sample surface. The method is applied respectively to prepare plan-view TEM specimens of a graphene sheet with multiple adlayers and MoS2 atomic layers. Useful electron diffraction results can be obtained from these specimens for understanding the interlayer orientation relationships in the two materials. Auger electron spectroscopy analysis further confirms that the sample surface is free from contamination under the sufficient protection given by the proposed method.

Platinum diselenide (PtSe

Perovskite α-CsPbI

Photocatalytic water splitting is a key technology for long-term hydrogen evolution with low environmental impact. In this work, an environment-friendly photocatalyst consisting of FeS2–TiO2 heterostructured nanocrystals has been successfully prepared by wet chemical synthesis for enhancing the photocatalytic hydrogen production rate over a wide range of absorption wavelengths. Its absorption range has been extended from the ultraviolet–visible to near-infrared (NIR) spectrum. The results of ultrafast optical spectroscopy suggest that charge transfer occurs between the FeS2 and TiO2 interface under NIR pulsed laser irradiation (800 nm). The highest photocatalytic hydrogen production rate of the FeS2–TiO2 heterostructure has been obtained in comparison with FeS2 nanocrystals (NCs) and TiO2 nanoparticles (NPs) under irradiation by a mercury arc lamp or a xenon lamp. In the FeS2–TiO2 heterostructure, the FeS2 NCs as a light harvester can efficiently absorb visible and NIR light to generate much more photoelectrons than TiO2 NPs only for hydrogen production. For long-term photocatalytic hydrogen production, the FeS2–TiO2 heterostructures also reveal an outstanding durability over 40 h. Overall, the FeS2–TiO2 heterostructure shows potential to be a TiO2-based photocatalyst for clean hydrogen production in practical applications.

Silicon is expected to be a useful anode material in lithium ion batteries for future energy storage applications, because of its high theoretical charge storage density of Li+ ions. However, volume expansion due to lithiation fractures the Si anode material, leading to poor cycle stability of battery operation. The approaches to overcome the problem include using Si nanowires to relieve the stress induced by volume expansion and coating a protective layer on the Si anode to prevent delamination. In this study, we use in-situ scanning electron microscopy to monitor the morphological changes of 90 nm thick pristine Si nanowires and the Si nanowires coated with amorphous TiO2, respectively, during electrochemical lithiation. The results of in-situ observation show that both kinds of Si nanowires exhibit a larger thickness after 10 h lithiation and suffer fracture after 25 h. It is also found that the TiO2 layer is not strong enough to prevent Si nanowires from fracture. Since the TiO2 layer can not be elastically deformed, this surface shell fractures earlier in the lithiation process than pristine Si nanowires. Transformation of the crystalline Si nanowires to an amorphous phase and lithium composition detected in the nanowires support that the observed fracture indeed results from lithiation.

Cellular reprogramming of somatic cells to patient-specific induced pluripotent stem cells (iPSCs) enables in-vitro modeling of human cardiac disorders for pathogenic and therapeutic investigations. However, using iPSC-derived cardiomyocytes (iPSC-CMs) to model an adult-onset heart disease remains challenging because of the uncertainty regarding the ability of relatively immature iPSC-CMs to fully recapitulate adult disease phenotypes. Arrhythmogenic right ventricular dysplasia (ARVD) is an inherited cardiomyopathy characterized by pathological fibrofatty infiltration and cardiomyocyte (CM) loss predominantly in the right ventricle (RV), leading to heart failure and lethal arrhythmias. Over 50% of affected individuals have desmosome gene mutations, most commonly inPKP2encoding plakophilin-2. Using Yamanaka's pluripotent factors, we generated iPSC lines from ARVD patients withPKP2mutations. We first developed a method to induce metabolic maturation of iPSC-CMs and showed that induction of adult-like metabolic energetics from an embryonic/glycolytic state is essential to model an adult-onset cardiac disease using patient-specific iPSCs. Furthermore, we showed that coactivation of normal peroxisome proliferator-activated receptor (PPAR)-α and abnormal PPARγ pathways in ARVD iPSC-CMs resulted in exaggerated CM lipogenesis, CM apoptosis, Na(+)channel downregulation and defective intracellular calcium handling, recapitulating the pathological signatures of ARVD. Using this model, we revealed novel pathogenic insights that metabolic derangement in an adult-like metabolic milieu underlies ARVD pathologies, enabling us to propose novel disease-modifying therapeutic strategies.

Recently, interest in aluminium ion batteries with aluminium anodes, graphite cathodes and ionic liquid electrolytes has increased; however, much remains to be done to increase the cathode capacity and to understand details of the anion–graphite intercalation mechanism. Here, an aluminium ion battery cell made using pristine natural graphite flakes achieves a specific capacity of ∼110 mAh g−1 with Coulombic efficiency ∼98%, at a current density of 99 mA g−1 (0.9 C) with clear discharge voltage plateaus (2.25–2.0 V and 1.9–1.5 V). The cell has a capacity of 60 mAh g−1 at 6 C, over 6,000 cycles with Coulombic efficiency ∼ 99%. Raman spectroscopy shows two different intercalation processes involving chloroaluminate anions at the two discharging plateaus, while C–Cl bonding on the surface, or edges of natural graphite, is found using X-ray absorption spectroscopy. Finally, theoretical calculations are employed to investigate the intercalation behaviour of choloraluminate anions in the graphite electrode., Rechargeable aluminium ion batteries are an emerging class of energy storage device. Here the authors reveal high-quality natural graphite as a promising cathode for Al-ion batteries, also identifying chloroaluminate anion intercalation in graphite by Raman spectroscopy.

Correction for ‘Extended visible to near-infrared harvesting of earth-abundant FeS2–TiO2 heterostructures for highly active photocatalytic hydrogen evolution’ by Tsung-Rong Kuo et al., Green Chem., 2018, 20, 1640–1647.

Northwest China is closely adjacent to Central Asia, an intermediate region of the Eurasian continent. Moreover, the Silk Road through the northwest of China once had a vital role in the east-west intercommunications. Nevertheless, little has been known about the genetic makeup of populations in this region. We collected 503 male samples from 14 ethnic groups in the northwest of China, and surveyed 29 Y-chromosomal biallelic markers and 8 short tandem repeats (STRs) loci to reconstruct the paternal architecture. Our results illustrated obvious genetic difference among these ethnic groups, and in general their genetic background is more similar with Central Asians than with East Asians. The ancestors of present northwestern populations were the admixture of early East Asians peopling northwestward and later Central Asians immigrating eastward. This population mixture was dated to occur within the past 10 000 years. The J2-M172 lineages likely entered China during the eastward migration of Central Asians. The influence from West Eurasia through gene flows on the extant ethnic groups in Northwest China was relatively weak.

The enhancement of light extraction from Si(0.5)Ge(0.5)/Si multiple quantum wells (MQWs) with nanowall structures fabricated by electron cyclotron resonance (ECR) plasma etching is presented. It is shown that the ECR plasma treatment does not damage the crystalline quality. At a driving current of 5.5 × 10(6) A m(-2), the light output intensity of the MQWs with nanowall structures shows an enhancement of about 50% compared with that of the original MQWs. In addition to the enhanced light extraction, the improved optoelectronic properties are also attributed to the strain relaxation in nanowall structures.