Synthesis-on-substrate of quantum dot solids.

Perovskite light-emitting diodes (PeLEDs) with an external quantum efficiency exceeding 20% have been achieved in both green and red wavelengths1-5; however, the performance of blue-emitting PeLEDs lags behind6,7. Ultrasmall CsPbBr3 quantum dots are promising candidates with which to realize efficient and stable blue PeLEDs, although it has proven challenging to synthesize a monodispersed population of ultrasmall CsPbBr3 quantum dots, and difficult to retain their solution-phase properties when casting into solid films8. Here we report the direct synthesis-on-substrate of films of suitably coupled, monodispersed, ultrasmall perovskite QDs. We develop ligand structures that enable control over the quantum dots' size, monodispersity and coupling during film-based synthesis. A head group (the side with higher electrostatic potential) on the ligand provides steric hindrance that suppresses the formation of layered perovskites. The tail (the side with lower electrostatic potential) is modified using halide substitution to increase the surface binding affinity, constraining resulting grains to sizes within the quantum confinement regime. The approach achieves high monodispersity (full-width at half-maximum = 23 nm with emission centred at 478 nm) united with strong coupling. We report as a result blue PeLEDs with an external quantum efficiency of 18% at 480 nm and 10% at 465 nm, to our knowledge the highest reported among perovskite blue LEDs by a factor of 1.5 and 2, respectively6,7.

Single-Atom Zinc Sites with Synergetic Multiple Coordination Shells for Electrochemical H2 O2 Production.

Precise manipulation of the coordination environment of single-atom catalysts (SACs), particularly the simultaneous engineering of multiple coordination shells, is crucial to maximize their catalytic performance but remains challenging. Herein, we present a general two-step strategy to fabricate a series of hollow carbon-based SACs featuring asymmetric Zn-N2 O2 moieties simultaneously modulated with S atoms in higher coordination shells of Zn centers (n≥2; designated as Zn-N2 O2 -S). Systematic analyses demonstrate that the synergetic effects between the N2 O2 species in the first coordination shell and the S atoms in higher coordination shells lead to robust discrete Zn sites with the optimal electronic structure for selective O2 reduction to H2 O2 . Remarkably, the Zn-N2 O2 moiety with S atoms in the second coordination shell possesses a nearly ideal Gibbs free energy for the key OOH* intermediate, which favors the formation and desorption of OOH* on Zn sites for H2 O2 generation. Consequently, the Zn-N2 O2 -S SAC exhibits impressive electrochemical H2 O2 production performance with high selectivity of 96 %. Even at a high current density of 80 mA cm-2 in the flow cell, it shows a high H2 O2 production rate of 6.924 mol gcat -1 h-1 with an average Faradaic efficiency of 93.1 %, and excellent durability over 65 h.

Ambient Ammonia Synthesis via Electrochemical Reduction of Nitrate Enabled by NiCo2 O4 Nanowire Array.

NiCo2 O4 nanowire array on carbon cloth (NiCo2 O4 /CC) is proposed as a highly active electrocatalyst for ambient nitrate (NO3 - ) reduction to ammonia (NH3 ). In 0.1 m NaOH solution with 0.1 m NaNO3 , such NiCo2 O4 /CC achieves a high Faradic efficiency of 99.0% and a large NH3 yield up to 973.2 µmol h-1  cm-2 . The superior catalytic activity of NiCo2 O4 comes from its half-metal feature and optimized adsorption energy due to the existence of Ni in the crystal structure. A Zn-NO3 - battery with NiCo2 O4 /CC cathode also shows a record-high battery performance.

Mesoporous N-rich Carbon with Single-Ni Atoms as a Multifunctional Sulfur Host for Li-S Batteries.

Physicochemical confinement and catalytic conversion of lithium polysulfides (LiPSs) are crucial to suppress the shuttle effect and enhance the redox kinetics of lithium-sulfur (Li-S) batteries. In this study, a NH4 Cl-assisted pyrolysis strategy is developed to fabricate highly mesoporous N-rich carbon (designed as NC(p)) featuring thin outer shells and porous inner networks, on which single-Ni atoms are anchored to form an excellent sulfur host (designed as Ni-NC(p)) for Li-S batteries. During pyrolysis, the pyrolytic HCl from confined NH4 Cl within ZIF-8 will in situ etch ZIF-8 to produce rich mesoporous in the carbonized product NC(p). The mesoporous Ni-NC(p) enables favorable electron/ion transfer, high sulfur loading, and effective confinement of LiPSs, while the catalytic effect of single-Ni species enhances the redox kinetics of LiPSs. As a result, the sulfur cathode based on the Ni-NC(p) host delivers obviously improved Li-S battery performance with high specific capacity, good rate capability, and cycling stability.

Rational Design and Engineering of One-Dimensional Hollow Nanostructures for Efficient Electrochemical Energy Storage.

The unique structural characteristics of one-dimensional (1D) hollow nanostructures result in intriguing physicochemical properties and wide applications, especially for electrochemical energy storage applications. In this Minireview, we give an overview of recent developments in the rational design and engineering of various kinds of 1D hollow nanostructures with well-designed architectures, structural/compositional complexity, controllable morphologies, and enhanced electrochemical properties for different kinds of electrochemical energy storage applications (i.e. lithium-ion batteries, sodium-ion batteries, lithium-sulfur batteries, lithium-selenium sulfur batteries, lithium metal anodes, metal-air batteries, supercapacitors). We conclude with prospects on some critical challenges and possible future research directions in this field. It is anticipated that further innovative studies on the structural and compositional design of functional 1D nanostructured electrodes for energy storage applications will be stimulated.

Phosphorized CoNi2 S4 Yolk-Shell Spheres for Highly Efficient Hydrogen Production via Water and Urea Electrolysis.

Exploring earth-abundant electrocatalysts with excellent activity, robust stability, and multiple functions is crucial for electrolytic hydrogen generation. Porous phosphorized CoNi2 S4 yolk-shell spheres (P-CoNi2 S4 YSSs) were rationally designed and synthesized by a combined hydrothermal sulfidation and gas-phase phosphorization strategy. Benefiting from the strengthened Ni3+ /Ni2+ couple, enhanced electronic conductivity, and hollow structure, the P-CoNi2 S4 YSSs exhibit excellent activity and durability towards hydrogen/oxygen evolution and urea oxidation reactions in alkaline solution, affording low potentials of -0.135 V, 1.512 V, and 1.306 V (versus reversible hydrogen electrode) at 10 mA cm-2 , respectively. Remarkably, when used as the anode and cathode simultaneously, the P-CoNi2 S4 catalyst merely requires a cell voltage of 1.544 V in water splitting and 1.402 V in urea electrolysis to attain 10 mA cm-2 with excellent durability for 100 h, outperforming most of the reported nickel-based sulfides and even noble-metal-based electrocatalysts. This work promotes the application of sulfides in electrochemical hydrogen production and provides a feasible approach for urea-rich wastewater treatment.

High-Performance Electrochemical NO Reduction into NH3 by MoS2 Nanosheet.

Electrochemical reduction of NO not only offers an attractive alternative to the Haber-Bosch process for ambient NH3 production but mitigates the human-caused unbalance of nitrogen cycle. Herein, we report that MoS2 nanosheet on graphite felt (MoS2 /GF) acts as an efficient and robust 3D electrocatalyst for NO-to-NH3 conversion. In acidic electrolyte, such MoS2 /GF attains a maximal Faradaic efficiency of 76.6 % and a large NH3 yield of up to 99.6 µmol cm-2 h-1 . Using MoS2 nanosheet-loaded carbon paper as the cathode, a proof-of-concept device of Zn-NO battery was assembled to deliver a discharge power density of 1.04 mW cm-2 and an NH3 yield of 411.8 µg h-1 mgcat. -1 . Calculations reveal that the positively charged Mo-edge sites facilitate NO adsorption/activation via an acceptance-donation mechanism and disfavor the binding of protons and the coupling of N-N bond.

Synergistic effect of uniform lattice cation/anion doping to improve structural and electrochemical performance stability for Li-rich cathode materials.

There has been extensive research into lithium-rich layered oxide materials as candidates for the nextgeneration of cathode materials in lithium-ion batteries, due to their high energy density and low cost; however, their poor cycle life and fast voltage fade hinder their large-scale commercial application. Here, we propose a novel cation/anion (Na+/PO4 3-) co-doping approach to mitigate the discharge capacity and voltage fade of a Co-free Li1.2Ni0.2Mn0.6O2 cathode. Our results show that the synergistic effect of cation/anion doping can promote long cycle stability and rate performance by inhibiting the phase transformation of the layered structure to a spinel or rock-salt structure and stabilizing the well-ordered crystal structure during long cycles. The co-doped sample exhibits an outstanding cycle stability (capacity retention of 86.7% after 150 cycles at 1 C) and excellent rate performance (153 mAh g-1 at 5 C). The large ionic radius of Na+ can expand the Li slab to accelerate Li diffusion and the large tetrahedral PO4 3- polyanions with high electronegativity stabilize the local structure to improve the electrochemical performance.

Rationally Designed Three-Layered Cu2 S@Carbon@MoS2 Hierarchical Nanoboxes for Efficient Sodium Storage.

Hybrid materials, integrating the merits of individual components, are ideal structures for efficient sodium storage. However, the construction of hybrid structures with decent physical/electrochemical properties is still challenging. Now, the elaborate design and synthesis of hierarchical nanoboxes composed of three-layered Cu2 S@carbon@MoS2 as anode materials for sodium-ion batteries is reported. Through a facile multistep template-engaged strategy, ultrathin MoS2 nanosheets are grown on nitrogen-doped carbon-coated Cu2 S nanoboxes to realize the Cu2 S@carbon@MoS2 configuration. The design shortens the diffusion path of electrons/Na+ ions, accommodates the volume change of electrodes during cycling, enhances the electric conductivity of the hybrids, and offers abundant active sites for sodium uptake. By virtue of these advantages, these three-layered Cu2 S@carbon@MoS2 hierarchical nanoboxes show excellent electrochemical properties in terms of decent rate capability and stable cycle life.

Synthesis of Copper-Substituted CoS2 @Cux S Double-Shelled Nanoboxes by Sequential Ion Exchange for Efficient Sodium Storage.

The construction of hybrid architectures for electrode materials has been demonstrated as an efficient strategy to boost sodium-storage properties because of the synergetic effect of each component. However, the fabrication of hybrid nanostructures with a rational structure and desired composition for effective sodium storage is still challenging. In this study, an integrated nanostructure composed of copper-substituted CoS2 @Cux S double-shelled nanoboxes (denoted as Cu-CoS2 @Cux S DSNBs) was synthesized through a rational metal-organic framework (MOF)-based templating strategy. The unique shell configuration and complex composition endow the Cu-CoS2 @Cux S DSNBs with enhanced electrochemical performance in terms of superior rate capability and stable cyclability.

Synthesis of Cobalt Sulfide Multi-shelled Nanoboxes with Precisely Controlled Two to Five Shells for Sodium-Ion Batteries.

We report the synthesis of cobalt sulfide multi-shelled nanoboxes through metal-organic framework (MOF)-based complex anion conversion and exchange processes. The polyvanadate ions react with cobalt-based zeolitic imidazolate framework-67 (ZIF-67) nanocubes to form ZIF-67/cobalt polyvanadate yolk-shelled particles. The as-formed yolk-shelled particles are gradually converted into cobalt divanadate multi-shelled nanoboxes by solvothermal treatment. The number of shells can be easily controlled from 2 to 5 by varying the temperature. Finally, cobalt sulfide multi-shelled nanoboxes are produced through ion-exchange with S2- ions and subsequent annealing. The as-obtained cobalt sulfide multi-shelled nanoboxes exhibit enhanced sodium-storage properties when evaluated as anodes for sodium-ion batteries. For example, a high specific capacity of 438 mAh g-1 can be retained after 100 cycles at the current density of 500 mA g-1 .

Nickel-Iron Layered Double Hydroxide Hollow Polyhedrons as a Superior Sulfur Host for Lithium-Sulfur Batteries.

We have designed and synthesized novel hollow Ni/Fe layered double hydroxide (LDH) polyhedrons as an advanced sulfur host for enhancing the performance of lithium-sulfur (Li-S) batteries. The Ni/Fe LDH host shows multiple advantages. First, the Ni/Fe LDH shells can provide sufficient sulfiphilic sites for chemically bonding with polysulfides. Second, the hollow architecture can provide sufficient inner space for both loading a large amount of sulfur and accommodating its large volumetric expansion. Moreover, once the active material is confined within the host, the shells could easily restrict the outward diffusion of polysulfides, guaranteeing prolonged cycle life even with high sulfur loading. As a result, the S@Ni/Fe LDH cathode has successfully solved the main issues related to sulfur electrodes, and it exhibits significantly improved electrochemical performances with prolonged life over 1000 cycles and excellent rate properties.

Sulindac has strong antifibrotic effects by suppressing STAT3-related miR-21.

Pulmonary fibrosis (PF) is a disease with an unknown cause and a poor prognosis. In this study, we aimed to explore the pathogenesis of PF and the mechanism of sulindac in attenuating bleomycin (BLM)-induced PF. The rat PF model was induced by BLM and verified through histological studies and hydroxyproline assay. The severity of BLM-induced PF in rats and other effects, such as the extent of the wet lung to bw ratios, thickening of alveolar interval or collagen deposition, was obviously ameliorated in sulindac-treated rat lungs compared with BLM-induced lungs. Sulindac also reversed the epithelial mesenchymal transition (EMT) and inhibited the PF process by restoring the levels of E-cadherin and α-smooth muscle actin (SMA) in A549 cells. Our results further demonstrated that the above effects of sulindac might be related to regulating of interferon gamma (IFN-γ) expression, which further affects signal transducers and activators of transcription 3 (STAT3) and phosphorylated STAT3 (p-STAT3) levels. Moreover, higher miR-21 levels with the decreased E-cadherin and increased α-SMA expressions were found in transforming growth factor-ß1-treated A549 cells, which can be reversed by sulindac. Collectively, our results demonstrate that by decreasing IFN-γ-induced STAT3/p-STAT3 expression to down-regulate miR-21, sulindac could significantly reverse EMT in A549 cells and prevent BLM-induced PF.

Theoretical and experimental study of organic nano-material for acetate anion based on 1, 10-phenanthroline.

New phenanthroline derivatives (1, 2, 3, 4) containing phenol groups have been synthesized and optimized. The nano-material of compound 2 was also developed. Their binding properties were evaluated for various biological anions (F(-), Cl(-), Br(-), I(-), AcO(-) and H(2)PO(4)(-)) by theoretical investigation, UV-vis, fluorescence, (1)HNMR titration experiments and these compounds all showed strong binding ability for AcO(-) without the interference of other anions tested. The anion binding ability could be regularized by electron push-pull properties of the ortho- or para- substituent on benzene. Theoretical investigation analysis revealed the effect of intramolecular hydrogen bond existed between -OH and other atoms in the structure of these compounds.

Evaluation of the hepatotoxicity of Psoralea corylifolia L. based on a zebrafish model.

Objective: Psoralea corylifolia L. (FP) has received increasing attention due to its potential hepatotoxicity. Methods: In this study, zebrafish were treated with different concentrations of an aqueous extract of FP (AEFP; 40, 50, or 60 µg/mL), and the hepatotoxic effects of tonicity were determined by the mortality rate, liver morphology, fluorescence area and intensity of the liver, biochemical indices, and pathological tissue staining. The mRNA expression of target genes in the bile acid metabolic signaling pathway and lipid metabolic pathway was detected by qPCR, and the mechanism of toxicity was initially investigated. AEFP (50 µg/mL) was administered in combination with FXR or a peroxisome proliferator-activated receptor α (PPARα) agonist/inhibitor to further define the target of toxicity. Results: Experiments on toxic effects showed that, compared with no treatment, AEFP administration resulted in liver atrophy, a smaller fluorescence area in the liver, and a lower fluorescence intensity (p < 0.05); alanine transaminase (ALT), aspartate transaminase (AST), and γ-GT levels were significantly elevated in zebrafish (p < 0.01), and TBA, TBIL, total cholesterol (TC), TG, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) levels were elevated to different degrees (p < 0.05); and increased lipid droplets in the liver appeared as fatty deposits. Molecular biological validation revealed that AEFP inhibited the expression of the FXR gene, causing an increase in the expression of the downstream genes SHP, CYP7A1, CYP8B1, BSEP, MRP2, NTCP, peroxisome proliferator-activated receptor γ (PPARγ), ME-1, SCD-1, lipoprotein lipase (LPL), CPT-1, and CPT-2 and a decrease in the expression of PPARα (p < 0.05). Conclusion: This study demonstrated that tonic acid extracts are hepatotoxic to zebrafish through the inhibition of FXR and PPARα expression, thereby causing bile acid and lipid metabolism disorders.

Tuberculosis infection following immune checkpoint inhibitor treatment for advanced cancer: a case report and literature review.

Objective: To investigate the clinical features of active tuberculosis (TB) infection due to immune checkpoint inhibitors (ICIs) treatment in patients with advanced cancer. Methods: We report the diagnosis and treatment of a case of pulmonary malignancy (squamous cell carcinoma, cT4N3M0 IIIC), secondary to active TB infection following ICIs therapy. Moreover, we summarize and analyze other related cases collected from the China National Knowledge Infrastructure (CNKI), Wanfang Database, PubMed, the Web of Science, and EMBASE (up to October 2021). Results: A total of 23 patients, including 20 males and 3 females who were aged 49-87 years with a median age of 65 years, were included in the study. Twenty-two patients were diagnosed by Mycobacterium tuberculosis culture or DNA polymerase chain reaction (PCR), while the remaining patient was diagnosed by tuberculin purified protein derivative and pleural biopsy. One case had an interferon-gamma release assay (IGRA) to rule out latent TB infection prior to the application of ICI. Fifteen patients received an anti-tuberculosis regimen. Among the 20 patients with a description of clinical regression, 13 improved and 7 died. Seven of the patients who improved were treated with ICI again and four of them did not experience a recurrence or worsening of TB. The case diagnosed in our hospital also improved after receiving anti-TB treatment after stopping ICI therapy, and continued chemotherapy on the basis of anti-TB treatment, and his condition is relatively stable at present. Conclusion: Due to the lack of specificity of TB infection following ICIs therapy, patients should be followed for fever and respiratory symptoms for 6.3 months after drug administration. It is recommended that IGRA should be performed before ICIs therapy and the development of TB during immunotherapy in patients who are positive in IGRA should be closely monitored. The symptoms of TB in most patients can be improved with ICIs withdrawal and anti-TB treatment, but there is still a need to be alert to the potentially fatal risk of TB.

Structural design of FeCo alloy implanted into N,S co-doped carbon nanotubes via self-catalyzed growth for advanced liquid and flexible all-state-state Zn-air battery.

The introduction of transition bimetallic alloys can effectively improve oxygen reduction reaction (ORR) activity. However, the alloy particles are inclined to dissolve under harsher conditions, resulting in a serious decrease in catalytic activity and stability. Herein, an efficient ORR catalyst, FeCo alloy nanoparticles (NPs) encapsulated in N,S co-doped carbon nanotubes (FeCo10-NSCNTs), was developed through a self-catalyzed growth strategy. Due to the delicate structural design, the N,S co-doped structure can effectively improve the ORR performance by modulating the electronic properties and surface polarity of the carbon substrate, and the randomly connected carbon nanotube structure with large specific surface area can further enhance the adsorption and dissociation of gas molecules, accelerating the kinetics of gas participation in the reaction. Carbon-encapsulated FeCo alloys are beneficial for improving catalytic activity and durability. The FeCo10-NSCNTs displayed excellent ORR activity with a half-wave potential of E1/2 = 0.84 V and robust stability of 13 k cycles. More impressively, the assembled liquid-state Zn-air battery (ZAB) with FeCo10-NSCNTs as the air-electrode delivers an output power density of 146.68 mW cm-2 along with excellent operation durability. The assembled all-solid ZAB has good cyclic stability under 0-180° bending conditions. The synthesized N,S co-doping, carbon nanotubes and FeCo alloys provide important guidance for the construction of cheap non-noble metal-carbon hybrid nanomaterials.

Plasmonic antenna effects on photochemical reactions.

Efficient solar energy conversion has been vigorously pursued since the 1970s, but its large-scale implementation hinges on the availability of high-efficiency modules. For maximum efficiency, it is important to absorb most of the incoming radiation, which necessitates both efficient photoexcitation and minimal electron-hole recombination. To date, researchers have primarily focused on the latter difficulty: finding a strategy to effectively separate photoinduced electrons and holes. Very few reports have been devoted to broadband sunlight absorption and photoexcitation. However, the currently available photovoltaic cells, such as amorphous silicon, and even single-crystal silicon and sensitized solar cells, cannot respond to the wide range of the solar spectrum. The photoelectric conversion characteristics of solar cells generally decrease in the infrared wavelength range. Thus, the fraction of the solar spectrum absorbed is relatively poor. In addition, the large mismatch between the diffraction limit of light and the absorption cross-section makes the probability of interactions between photons and cell materials quite low, which greatly limits photoexcitation efficiency. Therefore, there is a pressing need for research aimed at finding conditions that lead to highly efficient photoexcitation over a wide spectrum of sunlight, particularly in the visible to near-infrared wavelengths. As characterized in the emerging field of plasmonics, metallic nanostructures are endowed with optical antenna effects. These plasmonic antenna effects provide a promising platform for artificially sidestepping the diffraction limit of light and strongly enhancing absorption cross-sections. Moreover, they can efficiently excite photochemical reactions between photons and molecules close to an optical antenna through the local field enhancement. This technology has the potential to induce highly efficient photoexcitation between photons and molecules over a wide spectrum of sunlight, from visible to near-infrared wavelengths. In this Account, we describe our recent work in using metallic nanostructures to assist photochemical reactions for augmenting photoexcitation efficiency. These studies investigate the optical antenna effects of coupled plasmonic gold nanoblocks, which were fabricated with electron-beam lithography and a lift-off technique to afford high resolution and nanometric accuracy. The two-photon photoluminescence of gold and the resulting nonlinear photopolymerization on gold nanoblocks substantiate the existence of enhanced optical field domains. Local two-photon photochemical reactions due to weak incoherent light sources were identified. The optical antenna effects support the unprecedented realization of (i) direct photocarrier injection from the gold nanorods into TiO(2) and (ii) efficient and stable photocurrent generation in the absence of electron donors from visible (450 nm) to near-infrared (1300 nm) wavelengths.

Novel 3D Printed Vortex-like Flexible Roller-Compacted Triboelectric Nanogenerator for Self-Powered Electrochemical Degradation of Organic Contaminants.

It is an ideal way to use triboelectric nanogenerators (TENGs) to capture energy from the environment for the degradation of organic contaminants in water as a zero-carbon pathway. However, there is an urgent need to further develop TENGs with a simple structure and high output power. Herein, a novel TENG with a vortex-like flexible self-recovery blades of inner stator (denoted as VFR-TENG) is designed and manufactured with the assistance of a fused deposition modeling 3D printing technology. With the rotation of the outer rotor, a facile rotating contact-separation mode is achieved by the alternating arrangement of the flexible self-recovery blades. The contact tightness of the friction layer, a key factor for the transfer of charge density, can be easily adjusted by the thickness and arrangement style of the flexible self-recovery blades. The regulation of material elasticity and rotational frequency on the output characteristics is further investigated based on the special flexible structure. The VFR-TENG exhibits an instantaneous short-circuit current of 350 µA, an open-circuit voltage of 650 V, a transferred charge of 1.1 µC, and an optimum output power density of 4.4 W·m-2. This high-performance VFR-TENG is used for electrochemical degradation systems, which achieves excellent degradation efficiencies of 88.9, 91.7, and 94.1% for methylene blue, methyl orange, and malachite green within 150 min, respectively. This work provides a new idea for the design of flexible self-recovery contact-separation TENGs, which is of great inspiration for the exploitation of TENGs with both the high peak current and high-frequency characteristics for efficient water treatment.