Exploring the electrochemical properties of CuSe-decorated NiSe2 nanocubes for battery-supercapacitor hybrid devices.

Chalcogenides, a promising class of electrode materials, attracted massive popularity owing to their exciting features of high conductive nature, high capacity, rich redox activities, and structural functionalities, making them the first choice for the electrochemical energy domain. This paper reported a new NiSe2-CuSe nanocomposite prepared via a wet-chemical synthesis followed by a low-cost and simple hydrothermal reaction. The physical characterization showed cubes and nanoparticles type morphological features of NiSe2 and CuSe products, while their composite reveals a combined morphological characteristic. The electrochemical properties were tested in an aqueous solution, demonstrating that the NiSe2-CuSe nanocomposite exhibits a high capacity of 376 C g-1, low resistance, good reversibility and rate capability in a three-electrode mode than bulk counterparts. For practical aspects, a battery-hybrid supercapacitor (BHSC) is developed with NiSe2-CuSe nanocomposite, and activated carbon (AC) serves as cathode and anode in two-cell mode operation. The built NiSe2-CuSe||AC/KOH BHSC expanded the voltage to 1.8 V and delivered the highest capacitance of 148 F g-1 and 55 F g-1 from 1 to 10 A g-1, suppressing most of the previously existing literature reports. Also, our built NiSe2-CuSe||AC/KOH BHSC displayed a high-power delivery of 8928 W kg-1 at a maximum energy density of 66.6 W h kg-1 and retained 91.7% capacitance after a long way of 10,000 cycles. These outstanding results demonstrate that metal selenides can be effectively utilized as alternative electrodes with high energy, rate performance, and long-term durability for advanced energy conversion and storage devices.

Solvent-dependent supramolecular assembly behavior of a coumarin-headed amphiphile.

To study the effect of solvent on supramolecular self-assembly behaviors, a chiral courmarin-substituted glutamine amphiphile, L/DG-Cm, was synthesized for investigation. It was found that L/DG-Cm self-assembled into short nanotubes in toluene, while it formed longer nanotubes together with an obvious helix nanobelt structure for L/DG-Cm in DMSO, demonstrating that the nanotubes were formed by nanobelt rolling. The CD and CPL spectra revealed the same chiral property of the L/DG-Cm assemblies formed in toluene and DMSO. Theoretical calculations revealed that LG-Cm was prone to forming similar dimer structures in both DMSO and toluene. However, the distinct hierarchical packing ways in toluene and DMSO led to different nanostructures and chiroptical properties. Based on the temperature-dependent UV-visible and CD spectrometric measurements, LG-Cm was observed to aggregate in different supramolecular self-assembly modes, which was the cooperative (nucleation-elongation) mechanism in toluene and the isodesmic model in DMSO. This work proves that the solvent not only affects the self-assembly morphologies and properties but also determines the self-assembly pathways.

New drug approvals for 2021: Synthesis and clinical applications.

50 New drugs including 36 chemical entities and 14 biologics were approved by the U.S. Food and Drug Administration during 2021. Among the marketed drugs, 31 new small molecule agents (29 small molecule drugs and 2 diagnostic agents) with privileged structures and novel clinical applications represent as promising leads for the development of new drugs with the similar indications and improved therapeutic efficacy. This review is mainly focused on the clinical applications and synthetic methods of 29 small molecule drugs newly approved by the FDA in 2021. We believed that insight into the synthetic approaches of drug molecules would provide creative and practical inspirations for the development of more efficient and practical synthetic technologies to meet with new drug discovery.

Non-Ultrawide Bandgap Semiconductor GaSe Nanobelts for Sensitive Deep Ultraviolet Light Photodetector Application.

In this paper, the authors report the fabrication of a sensitive deep ultraviolet (DUV) photodetector by using an individual GaSe nanobelt with a thickness of 52.1 nm, which presents the highest photoresponse at 265 nm illumination with a responsivity and photoconductive gain of about 663 A W-1 and 3103 at a 3 V bias, respectively, comparable to or even better than other reported devices based on conventional wide bandgap semiconductors. According to the simulation, this photoelectric property is associated with the wavelength-dependent absorption coefficient of the GaSe crystal, for which incident light with shorter wavelengths will be absorbed near the surface, while light with longer wavelengths will have a larger penetration depth, leading to a blueshift of the absorption edge with decreasing thickness. Further finite element method (FEM) simulation reveals that the relatively thin GaSe nanobelt exhibits an enhanced transversal standing wave pattern compared to its thicker counterpart at a wavelength of 265 nm, leading to an enhanced light-matter interaction and thereby more efficient photocurrent generation. The device can also function as an effective image sensor with acceptable spatial resolution. This work will shed light on the facile fabrication of a high-performance DUV photodetector from non-ultrawide bandgap semiconductors.

Spectral Engineering of InSe Nanobelts for Full-Color Imaging by Tailoring the Thickness.

In this work, we report on the synthesis of InSe nanobelts through a catalyst-free chemical vapor deposition (CVD) growth approach. A remarkable blue shift of the peak photoresponse was observed when the thickness of the InSe nanobelt decreases from 562 to 165 nm. Silvaco Technology Computer Aided Design (TCAD) simulation reveals that such a shift in spectral response should be ascribed to the wavelength-dependent absorption coefficient of InSe, for which incident light with shorter wavelengths will be absorbed near the surface, while light with longer wavelengths will have a greater penetration depth, leading to a red shift of the absorption edge for thicker nanobelt devices. Considering the above theory, three kinds of photodetectors sensitive to blue (450 nm), green (530 nm), and red (660 nm) incident light were achieved by tailoring the thickness of the nanobelts, which can enable the spectral reconstruction of a purple "H" pattern, suggesting the potential application of 2D layered semiconductors in full-color imaging.

Dual-cation-doped MoS2nanosheets accelerating tandem alkaline hydrogen evolution reaction.

Molybdenum disulfide (MoS2) nanosheets are promising candidates as earth-abundant and low-cost catalyst for hydrogen evolution reaction (HER). Nevertheless, compared with the benchmark Pt/C catalyst, the application of MoS2nanosheets is limited to its relatively low catalytic activity, especially in alkaline environments. Here, we developed a dual-cation doping strategy to improve the alkaline HER performance of MoS2nanosheets. The designed Ni, Co co-doped MoS2nanosheets can promote the tandem HER steps simultaneously, thus leading to a much enhanced catalytic activity in alkaline solution. Density functional theory calculations revealed the individual roles of Ni and Co dopants in the catalytic process. The doped Ni is uncovered to be the active site for the initial water-cleaving step, while the Co dopant is conducive to the H desorbing by regulating the electronic structure of neighboring edge-S in MoS2. The synergistic effect resulted by the dual-cation doping thus facilitates the tandem HER steps, providing an effective route to raise the catalytic performance of MoS2materials in alkaline solution.

Fabrication of Addressable Perovskite Film Arrays for High-Performance Photodetection and Real-Time Image Sensing Application.

Patterned growth of periodic perovskite film arrays is essential for application in sensing devices and integrated optoelectronic systems. Herein, we report on patterned growth of addressable perovskite photodetector arrays through an uncured polydimethylsiloxane (PDMS) oligomer-assisted solution-processed approach, in which a periodic hydrophilic/hydrophobic substrate replicating the predesigned patterns of the PDMS stamp was formed due to the migration of uncured siloxane oligomers in the PDMS stamp to the intimately contacted substrate. By using this technique, MAPbI3 film photodetector arrays with neglectable pixel-to-pixel variation, a responsivity of 2.83 A W-1, specific detectivity of 5.4 × 1012 Jones, and fast response speed of 52.7/57.1 µs (response/recovery time) were achieved. An 8 × 8 addressable photodetector array was further fabricated, which functioned well as a real-time image sensor with reasonable spatial resolution. It is believed that the proposed strategy will find potential application in large-scale fabrication of other photodetector arrays, which might be potentially important for future integrated optoelectronic devices.

Topological Formation of a Mo-Ni-Based Hollow Structure as a Highly Efficient Electrocatalyst for the Hydrogen Evolution Reaction in Alkaline Solutions.

A Mo-Ni alloy has been demonstrated to be a benchmark noble-metal-free catalyst for the hydrogen evolution reaction (HER) in alkaline solutions. Nevertheless, further improvement on its catalytic activity is desired to meet industrial requirements. In this study, Mo-Ni-based hollow structures (MoNi-HS), backboned by MoO3- x nanosheets and decorated with metallic MoNi4 nanoparticles, were obtained via a topological transformation process by annealing MoNi-oxide hollow precursors in a reducing atmosphere. This hollow structure allowed for a large proportion of catalytic surface exposed in the electrolyte, leading to highly efficient utilization of active sites in the catalyst. As a result, robust catalytic activity toward HER was recorded in 1 M KOH electrolyte: a low overpotential of 38 mV to deliver a current density of 10 mA/cm2 and a very small Tafel slope of 31.4 mV per dec. Such a remarkable performance of MoNi-HS even outperformed the catalytic activity of the commercial Pt/C electrocatalyst, addressing an effective strategy to promote the catalytic performance of noble-metal-free catalysts.

First-Row Transition Metal Based Catalysts for the Oxygen Evolution Reaction under Alkaline Conditions: Basic Principles and Recent Advances.

Owing to its abundance, high gravimetric energy density, and environmental friendliness, hydrogen is a promising renewable energy to replace fossil fuels. One of the most prominent routes toward hydrogen acquisition is water splitting, which is currently bottlenecked by the sluggish kinetics of oxygen evolution reaction (OER). Numerous of electrocatalysts have been developed in the past decades to accelerate the OER process. Up to now, the first-row transition metal based compounds are in pole position under alkaline conditions, which have become subjects of extensive studies. Recently, significant advances in providing compelling catalytic performance as well as exploring their catalytic mechanisms have been achieved in this area. In this review, we summarized the fundamentals and recent progresses in first-row transition metal based OER catalysts, with special emphasis on the pathways of promoting catalytic performance by concrete strategies. New insight into material design, particularly the role of experimental approaches in the electrocatalytic performance and reaction mechanisms of OER are expected to be provided.

CTAB-Assisted Fabrication of Bi2WO6 Thin Nanoplates with High Adsorption and Enhanced Visible Light-Driven Photocatalytic Performance.

Two-dimensional thin Bi2WO6 nanoplates have been fabricated using a cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal method. We investigated the proposed formation mechanism based on the crystalline structures of the thin Bi2WO6 nanoplates. The high adsorption ability and excellent visible-light driven photocatalytic activities of the Bi2WO6 nanoplates were illustrated, in view of exposed (001) facets of nanoplates possessing faster separation of photo-generated charge carriers and increased catalytically active sites. Such a cost-effective way to obtain Bi2WO6 nanoplates offers new possibilities for the design of adsorptive semiconductor photocatalysts with strengthened photocatalytic activities.

Nanoparticle siRNA against BMI-1 with a Polyethylenimine-Laminarin Conjugate for Gene Therapy in Human Breast Cancer.

The B-cell-specific Moloney leukemia virus inset site 1 gene (BMI-1) has attracted considerable attention in recent years because of its key role in breast cancer development and metastasis. The downregulation of BMI-1 expression via small interfering RNA (siRNA) effectively inhibits tumor growth. However, the successful application of this therapy is limited by the unavailability of an appropriate vector for siRNA transfer. Therefore, this study aimed to construct a novel laminarin-based nonviral gene transfer vector to carry a constructed BMI-1-targeting siRNA and to investigate the in vitro and in vivo antitumor effects of this siRNA on breast cancer cells. To enhance the siRNA-carrying capacity, we introduced polyethylenimine (PEI) to laminarin's surface via N,N'-carbonyldiimidazole, which produced the cationic PEI-modified laminarin conjugate nLP. Subsequent in vitro experiments indicated that nLP not only formed a nanoparticle with a diameter of 200 nm through electrostatic interactions with siRNA but also showed high efficiency (95.0%) in the delivery siRNA to MCF-7 cells. The nanoparticle targeting BMI-1 (nLP/siBMI-2) reduced BMI-1 expression in breast MCF-7 cells by 90.9% reduction. An in vivo tumor suppression experiment demonstrated that the nLP/siBMI-2 nanoparticle had relatively low toxicity and good gene-therapeutic efficacy, with a tumor inhibition rate of 46.6%.

Fe3O4@Bi2WO6 Core-Shell Structured Microspheres: Facile Construction and Magnetically Recyclable Photocatalytic Activity Under Visible-Light.

Core-shell structured Fe3O4@Bi2WO6 composite microspheres (Fe3O4 microspheres as core and Bi2WO6 nanoplates as shell) have been fabricated in a facile and cost effective reflux way. Such fabricated Fe3O4@Bi2WO6 composites show good visible-light driven photocatalytic performance on degradation of rhodamine B (RhB) from solution in presence of H2O2. More importantly, they can be easily harvested from aqueous system for recycle with small loss of their photocatalytic activity upon applying an external magnet. However, this combination of Bi2WO6 photocatalytic activity and Fe3O4 magnetic property endows such composite with a bright perspective in low cost waste water treatment by taking full advantage of solar energy.

Photogenerated carriers transfer in dye-graphene-SnO2 composites for highly efficient visible-light photocatalysis.

The visible-light-driven photocatalytic activities of graphene-semiconductor catalysts have recently been demonstrated, however, the transfer pathway of photogenerated carriers especially where the role of graphene still remains controversial. Here we report graphene-SnO2 aerosol nanocomposites that exhibit more superior dye adsorption capacity and photocatalytic efficiency compared with pure SnO2 quantum dots, P25 TiO2, and pure graphene aerosol under the visible light. This study examines the origin of the visible-light-driven photocatalysis, which for the first time links to the synergistic effect of the cophotosensitization of the dye and graphene to SnO2. We hope this concept and corresponding mechanism of cophotosensitization could provide an original understanding for the photocatalytic reaction process at the level of carrier transfer pathway as well as a brand new approach to design novel and versatile graphene-based composites for solar energy conversion.

Sacrificial templating synthesis of hematite nanochains from [Fe18S25](TETAH)14 nanoribbons: their magnetic, electrochemical, and photocatalytic properties.

Unique hematite nanochains self-assembled from α-Fe(2)O(3) nanoparticles can be synthesized by thermal decomposition of [Fe(18)S(25)](TETAH)(14) as an appropriate nanoribbon precursor (TETAH = protonated triethylenetetramine). Magnetic studies have revealed greatly enhanced coercivity of the 1D hematite nanochains compared with that of dispersed α-Fe(2)O(3) nanoparticles at low temperature, which may be attributed to their increased shape anisotropy and magnetocrystalline anisotropy. The photocatalytic properties of the hematite nanochains have been studied, as well as their electrochemical properties as cathode materials of lithium-ion batteries. The results have shown that both properties are dependent on the BET specific surface areas of the 1D hematite nanochains.

Hierarchical hollow Co9S8 microspheres: solvothermal synthesis, magnetic, electrochemical, and electrocatalytic properties.

A simple solvothermal route in a binary solution of triethylenetetramine (TETA) and deionized water (DIW) has been used to synthesize hierarchical hollow Co(9)S(8) microspheres with high surface area (80.38 m(2) g(-1)). An appropriate volume ratio of TETA:DIW has been found to be essential for the formation of hollow Co(9)S(8) microspheres. The magnetic study indicated that the Co(9)S(8) hollow microspheres are paramagnetic at high temperature and antiferromagnetic at low temperature. The oxygen reduction reaction experiments demonstrated that the onset potential of the Co(9)S(8) sample is 0.88 V, which is comparable to the value predicted for Co(9)S(8) (0.74 V) from the theoretical simulation. The discharge capability of Co(9)S(8) hollow microspheres as cathode materials for lithium ion batteries and their electrocatalytic activity for the oxygen reduction reaction (ORR) have been studied.

Hierarchical FeWO4 microcrystals: solvothermal synthesis and their photocatalytic and magnetic properties.

Highly hierarchical platelike FeWO(4) microcrystals have been synthesized by a simple solvothermal route using FeCl(3) x 6 H(2)O and Na(2)WO(4) x 2 H(2)O as precursors, where ethylene glycol (EG) plays an important role as a capping agent in directing growth and self-assembly of such unique structures. In addition, a certain amount of CH(3)COONa (NaAc) was necessary for the formation of such unique FeWO(4) microstructures. The photocatalytic property of as-synthesized hierarchical FeWO(4) microcrystals has been first studied, which shows excellent photocatalytic activity for the degradation of rhodamine B (RhB) under UV and visible light irradiation (modeling sunlight). Moreover, magnetic measurement indicates that hexangular FeWO(4) platelike microcrystals show a small ferromagnetic ordering at low temperature because of spin-canting of antiferromagnetic materials and surface spins of FeWO(4) nanoparticles.