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Due to the scarcity of the noble metals and their high price, the use of carbon-based materials to replace the noble metal catalysts has attracted extensive current research interest. Herein, we reported that carbon quantum dots (CQDs) can be used to replace Pd nanoparticles in hydrogenation reactions due to the presence of the frustrated Lewis acid-base pairs (FLPs), as demonstrated experimentally and supported theoretically. By coupling the hydrogenation of imines over CQDs with ZnIn2S4-based photocatalytic dehydrogenation of alcohols, N-alkylation of amines with alcohols have been successfully realized over CQDs/ZnIn2S4, with performance comparable to that observed over Pd/ZnIn2S4 nanocomposite, demonstrating the possibility of using CQDs to substitute Pd nanoparticles in hydrogenation of imines. This work shows enormous potential of employing the CQDs in chemical reactions to reduce the current dependence on noble metal-based catalysts.

We report charge recombination rates in lead iodide perovskites with alloys of formamidinium (FA) and methylammonium (MA) cations, FAxMA1–xPbI3, 0 ≤ x ≤ 0.9, prepared through ion exchange with mini...

The morphology and optoelectronic properties of perovskite films are the key to high-performance perovskite solar cells (PSCs). Here, a facile non-destructive interface ethanol/chlorobenzene (EtOH/CB) post treatment was established for the lateral grain growth of MAPbI3 perovskite films and fabrication of efficient solar cells. The alcoholic treatment leads to perovskite grain coarsening and a secondary growth in the average grain size from 38.88 μm to 89.59 μm. The enlargement of the perovskite crystals induced a notable defect passivation and attenuated charge recombination centers as confirmed by photoluminescence, electrochemical impedance spectroscopy, and photocharge extraction by a linearly-increasing voltage. Accordingly, inverted planar PSC devices showed an 18% enhancement in the overall power conversion efficiency using this alcoholic post-treatment under ambient fabrication conditions. Our results demonstrate a versatile strategy for the lateral growth of perovskite photovoltaics and beyond.

Carrier transport layers have been recognized as a key factor to determine the performance of perovskite solar cells (PSCs) by dominating the charge carrier extraction, transport and recombination process. Metal oxides have been widely used as electron transport layers (ETLs) in PSCs for high performance and stability, of which TiO2 and SnO2 are the most popular choices. However, the large-scale implementation of TiO2 and SnO2 ETLs is hindered by their own deficiencies, such as low electron mobility, poor stability against UV light and surface defects. Therefore, binary and ternary metal oxide alternatives have been widely investigated recently. Here, we review the recent advances of these metal oxide ETLs in PSCs with a special focus on the nanostructuring, elemental doping, surface modification, and multi-layer ETLs and large-scale fabrication of these ETLs. Furthermore, the state-of-the-art progress towards high-efficiency and stable PSCs using these novel ETLs is summarized and future perspectives are discussed.

Halide perovskite solar cells (PSCs) have been materialized as a hotspot in the next-generation photovoltaic technology due to their low-cost manufacturing process and high-efficiency characteristics. However, the defects within the bulk or in the grain boundaries and surface hinder ambipolar charge transport as non-radiative recombination centers. Efficacious defect passivation is therefore highly desired for high-efficiency and stable PSCs. Herein, a feasible Lewis acid/base passivation strategy and its effects on energy level alignment, recombination kinetics, hysteresis behavior and operational stability for efficient PSCs are comprehensively reviewed. These additives have been widely used to coordinate with unwanted defects and form Lewis adducts by dative bonds, where the Lewis acid contributes to passivate negatively charged defects (e.g., under-coordinated I− ions and Pb–I anti-sites) and the Lewis base plays a significant role in passivating positively charged defects (e.g., under-coordinated Pb2+ and Pb2+ interstitials), whereas zwitterions could passivate negatively and positively charged defects simultaneously. This highly executable Lewis adduct passivation would enable scalable deposition techniques for efficient and stable PSCs like inkjet printing, doctor-blade coating, screen printing, laser pattering and roll-to-roll deposition. Additionally, we also discuss the prospects of the maturity of this passivation strategy towards upscaling manufacture of perovskite photovoltaic and related optoelectronic devices.

MOF-253 (Al(OH)(dcbpy), dcbpy = 2,2'-bipyridine-5,5'-dicarboxylic acid) obtained via a microwave-assisted synthesis was used for the construction of a supported Ru complex containing dcbpy (MOF-253-Ru(dcbpy)2) by coordinating its open N,N'-chelating sites with Ru(II) in Ru(dcbpy)2Cl2. The as-obtained MOF-253-Ru(dcbpy)2 acts as a bifunctional photocatalyst for simultaneous CO2 reduction to produce formic acid and CO, as well as semidehydrogenation of 1,2,3,4-tetrahydroisoquinoline (THIQ) to obtain 3,4-dihydroisoquinoline (DHIQ). The performance over the surface-supported MOF-253-Ru(dcbpy)2 is superior to that over Ru-doped MOF-253 (Ru-MOF-253) obtained via a mix-and-match strategy, indicating that the use of open coordination sites in the MOFs for direct construction of a surface-supported complex is a superior strategy to obtain an MOF-supported homogeneous complex. This study shows the possibility of using an MOF as a platform for the construction of multifunctional heterogeneous photocatalytic systems. The coupling of photocatalytic CO2 reduction with the highly selective dehydrogenation of organics provides an economical and green strategy in photocatalytic CO2 reduction and production of valuable organics simultaneously.

MoS2/ZnIn2S4 nanocomposite was prepared via photoreduction of (NH4)2MoS4 in the presence of hexagonal ZnIn2S4. The as-obtained MoS2/ZnIn2S4 nanocomposite showed superior activity for acceptorless photocatalytic semi-dehydrogenation of 1,2,3,4-tetrahydroisoquinoline to produce 3,4-dihydroisoquinoline, with quantitative hydrogen evolved. In addition to MoS2/ZnIn2S4, a series of MS/ZnIn2S4 nanocomposites (MS = PtS and NiS) were also found to be active for this reaction, indicating that ZnIn2S4-based nanocomposites are effective photocatalysts for acceptorless semi-dehydrogenation of 1,2,3,4-tetrahydroisoquinoline to produce 3,4-dihydroisoquinoline. This study not only provides an efficient, green and cost effective strategy to produce 3,4-dihydroisoquinoline, but also highlights the great potential of semiconductor-based photocatalysis for light-driven organic syntheses.

A novel gas separation approach is proposed in this work by combining an amine-based solid adsorbent with a zeolitic imidazolate framework-8 (ZIF-8) membrane. This was achieved by incorporating the amine-based solid adsorbent during the fabrication of the ZIF-8 membrane on a macroporous substrate. An amine-based solid adsorbent was prepared using porous ZIF-8-3-isocyanatopropyltrimethoxysilane (IPTMS) and N-[(3-trimethoxysilyl)propyl]diethylenetriamine (3N-APS) amine compounds. The as-prepared porous amine-based solid adsorbent (denoted as ZIF-8-IPTMS-3N-APS) possessed excellent adsorptive CO2/N2 and CO2/CH4 separation performances. As the adsorbent needs to be regenerated, this could indicate that the CO2 adsorption separation process cannot be continuously operated. In this work, an amine-based solid adsorbent was applied during the preparation of the ZIF-8 membranes owing to the following reasons: (i) gas separation by the membrane can be operated continuously; (ii) the amino group provides a heterogeneous nucleation site for ZIF-8 to grow; and (iii) the reparation of surface defects on the macroporous substrate can be performed prior to the growth of the ZIF-8 membrane. Herein, the ZIF-8 membrane was successfully fabricated, and it possessed excellent CO2/CH4, CO2/N2, and H2/CH4 separation performances. The 0.6 μm ultrathin ZIF-8 membrane demonstrated a high CO2 permeance of 4.75 × 10−6 mol m−2 s−1 Pa−1 at 35 °C and 0.1 MPa, and ideal CO2/N2 and CO2/CH4 selectivities of 4.67 and 6.02, respectively. Furthermore, at 35 °C and 0.1 MPa, the ideal H2/CH4 selectivity of the ZIF-8 membrane reached 31.2, and a significantly high H2 permeance of 2.45 × 10−5 mol m−2 s−1 Pa−1.

Brucella are serious intracellular pathogens that parasitize macrophages and cause persistent infection in humans and animals. Although macrophages are an important bridge between natural and acquired immunity, their role in Brucella infection is not completely clear. Recently, studies have reported that Brucella can induce macrophage polarization, although the specific molecular mechanism involved is not known. Therefore, in the current study the replication ability of Brucella melitensis strain M5 (Brucella M5) was examined as well as its macrophage polarization and cytokine production, in a host. The role of Signal transducers and activators of transcription 6 (STAT6) in macrophage polarization induced by Brucella infection was also investigated. The results showed that Brucella M5 survived in vivo for a prolonged period of time and caused damage to the spleen and uterus tissues. The expression of type M2 cytokines was induced after Brucella M5 infection. Immunohistochemistry showed that STAT6 was upregulated in spleen and uterus tissues. At the cellular level, Brucella M5 induced macrophagetransformation from M1 to M2-type during the later stage of infection. When STAT6 was silenced, the polarization of M2-type was inhibited, and the intracellular survival rate of Brucella decreased significantly. In conclusion, these findings demonstrate that STAT6 is the key factor regulates M2 polarization of macrophages and promotes the intracellular survival of Brucella in the late stage of infection and provides an explanation of the mechanism responsible for persistent Brucella infection.

The enzootic and zoonotic nature of H9N2 avian influenza viruses pose a persistent threat to global poultry industry and human health. This particular subtype influenza virus raises public concerns because it possesses human receptor specificity. In this study, four H9N2 virus strains clustered into the G57-like viruses preferentially bound to SAα2,6 receptors as demonstrated in the results from the receptor-binding assay. The molecular dynamic simulation showed that HAQ226L substitution of H9N2 viruses may alter the conformation of the 220-loop of hemagglutinin (HA) and thus optimize the contacts between HA and human receptors, thereby increasing the preference for α2,6-linkages. The acquisition of an additional N-glycosylation site at position 264 close to the enzyme active sites of neuraminidase of H9N2 viruses induced the loss of hydrogen bonding between 276E at the enzyme active sites and Zanamivir and further led to occurrence of Zanamivir-resistant of viruses. This study shows the relationship between the conformational changes due to amino acid variations and viral biological phenotypes, which emphasizes the necessity for monitoring the continual evolution of H9N2 viruses and comprehensively assessing their potential zoonotic threat.

A two-stage anoxic/oxic (A/O)-moving bed biofilm reactor (MBBR) system with multiple chambers was established for municipal wastewater treatment. At the total hydraulic retention time (HRT) of 11.2 h and nitrate recycling ratio of 1, the removal efficiencies reached 83.8%, 82.5%, and 77.8% for soluble chemical oxygen demand (SCOD), 98.0%, 97.5%, and 94.9% for ammonia nitrogen (NH

As one of the most sensitive areas to global environmental change, especially global climate change, the Qinghai–Tibet Plateau is an ideal area for studying global climate change and ecosystems. There are few studies on the analysis of the vegetation’s driving factors on the Qinghai–Tibet Plateau based on large-scale and high-resolution data due to the incompetence of satellite sensors. In order to study the long-term vegetation spatiotemporal pattern and its driving factors, this study used the enhanced spatial and temporal adaptive reflectance fusion model (ESTARFM) to improve the spatial resolution of the GIMMS NDVI3g (8 km) data of the Qinghai–Tibet Plateau in 1990 and 1995 based on the MODIS NDVI (500 m) data. The research on the spatiotemporal pattern and driving factors of vegetation on the Qinghai–Tibet Plateau from 1990 to 2015 was carried out afterward, with combined data including topographic factors, annual average temperature, and annual precipitation. The results showed that there was a strong correlation between the actual MODIS NDVI image and the fused GIMMS NDVI3g image, which means that the accuracy of the fused GIMMS NDVI3g image is reliable and can provide basic data for the accurate evaluation of the spatial and temporal patterns of vegetation on the Qinghai–Tibet Plateau. From 1990 to 2015, the overall vegetation coverage of the Qinghai–Tibet Plateau showed a degrading trend at a rate of −0.41%, and the degradation trend of vegetation coverage was the weakest when the slope was ≥25°. Due to the influence of the policy of returning farmland to forests, the overall degradation trend has gradually weakened. The significant changes in vegetation in 2010 can be attributed to the difference in the spatial distribution of climatic factors such as temperature and precipitation. The area with reduced vegetation in the west was larger than the area with increased vegetation in the east. The effects of temperature and precipitation on the distribution, direction, and degradation level of vegetation coverage were varied by the areal differentiation in different zones.

This is a reply to A. A. Katanin's comment [A. A. Katanin, Nat. Commun. 12, 1433 (2021); arXiv:2103.02966] on our paper [X. Deng et al., Nat. Commun. 10, 2721 (2019); arXiv:1708.05752].

Additional file 1: Table S1. Clinical and laboratory data of the patient with Brucella endocarditis and spondylitis.

Brucella is a genus of Gram-negative intracellular pathogens that cause animal and human diseases. Brucella survival and replication inside immune cells is critical for the establishment of chronic infections. Protein modifications by small ubiquitin-related modifier proteins and the NF-κB pathway are involved in many cellular activities, playing major roles in regulating protein function that is essential for pathogenic bacteria during infection. However, the relationship between them in the intracellular survival of Brucella is still largely unknown. We demonstrated that Brucella abortus 2308 infection can activate the expression of small ubiquitin-related modifier-2 proteins in a time-dependent manner. We found the production of Th1 cytokines (IFN-γ and TNF-α) and the transcription of NF-κB/p65 were promoted by overexpression and inhibited by interference of small ubiquitin-related modifier-2. In addition, we showed that small ubiquitin-related modifier-2 can inhibit intracellular survival of Brucella abortus 2308 by regulating activation of the NF-κB pathway. Taken together, this work shows that small ubiquitin-related modifier-2 modification of NF-κB2/p65 is essential for the survival of Brucella abortus 2308 inside macrophages. This work may help to unravel the pathogenic mechanisms of Brucella infections.

Naturally occurring cyclic antimicrobial peptides (AMPs) such as tyrocidine A (Tyrc A) and gramicidin S (GS) are appealing targets for the development of novel antibiotics. However, their therapeutic potentials are limited by undesired hemolytic activity and relatively poor activity against Gram-negative bacteria. Inspired by polycationic lipopeptide polymyxin B (PMB), the so called ‘last-resort’ antibiotic for the treatment of infections caused by multidrug-resistant Gram-negative bacteria, we synthesized and biologically evaluated a series of polycationic analogues derived from Tyrc A. We were able to obtain peptide 8 that possesses 5 positive charges exhibiting potent activities against both Gram-negative and Gram-positive bacteria along with totally diminished hemolytic activity. Intriguingly, antibacterial mechanism studies revealed that, rather than the ‘pore forming’ model that possessed by Tyrc A, peptide 8 likely diffuses membrane in a ‘detergent-like’ manner. Furthermore, when treating mice with peritonitis–sepsis, peptide 8 showed excellent antibacterial and anti-inflammatory activities in vivo.

The H1N1 subtype influenza viruses (H1N1) have been causing persistent epidemics in human, swine and poultry populations since 1918. This subtype has evolved into four relatively stable genetic lineages, including classical swine influenza virus lineage, seasonal human influenza virus lineage, avian influenza virus lineage and Eurasian avian-like swine influenza virus lineage. In this study, four pairs of primers, based on the relatively conserved HA nucleotide regions of each H1N1 genetic lineage, were designed to establish an SYBR Green-based real-time quantitative RT-PCR (qPCR) assay to differentiate between the H1N1 genetic lineages. The results of qPCR assay showed that the lineage-specific primers designed for each H1N1 lineage were intra-lineage-specific, without mismatch of inter-lineage or inter-subtype and there appeared specific amplification curves when the concentrations of H1N1 plasmids were greater than or equal to 1.0 × 101 copies/reaction. Thus, this qPCR assay can specifically differentiate between the four lineages of H1N1 with a good specificity and sensitivity, which would assist in recognizing the infection and epidemic status of different H1N1 genetic lineages.

The FMDV VP1 protein has different structures which could decrease or increase the immune response. We undertook a meta-analysis to evaluate the protective effect of VP1 on the FMDV. A systematic search of the PubMed, Embase, CNKI and Wan fang DATA was conducted up to April 2020. Experimental studies involving the VP1 protection effect on FMDV were included. Extracted data were analyzed using Rev-Man 5.3 software. Chi-square tests were used to analyze the heterogeneity among the documents. The fixed-effect model was used for meta-analysis to find the combined effect value and 95% confidence interval. Sensitivity analysis was performed on the differences in the combined values of model effects, and the inverted funnel chart method was used to assess the publication bias of the included literature. A total of 12 articles were included for meta-analysis. The results of showed that VP1 had a protective effect on FMDV [MH = -0.66, 95% CI = (−0.75, -0.56), P < 0.00001]. Sensitivity analysis showed that the results were robust. The funnel graph method showed that the published literature had a small publication bias and met the requirements of this study. It is necessary to study the epitopes of VP1 to produce new vaccines. VP1 could protect animals from FMDV attacks. It is necessary to study the VP1 protein and its epitopes and use it as a new vaccine and diagnostic product.

Utilization of non-lithium-ion batteries in next-generation renewable energy storage is hindered by the lack of appropriate electrode materials with desired electrochemical performance. Motivated by low peeling-off energy (Jing et al. Nano Lett. 2017, 17(3), 1833−1838), an experimentally available two-dimensional material, nominated as GeP3, is investigated as the anode for non-lithium-ion batteries (Na+, K+, Ca2+, Mg2+, Al3+) based on density functional theory calculations. The electrochemical properties, i.e., ion intercalation mechanism, diffusion behavior, and theoretical capacities of different metal ions in GeP3, are systematically investigated. A semiconductor-to-metal transition and improved conductivity are observed due to ions intercalation in the GeP3 electrode. Even though the charge storage mechanism of Na and Ca ions is quite different, the GeP3 monolayer has exhibited a high theoretical capacity of 1295.42 mAh g–1 for both Na+ and Ca2+ ions. Furthermore, collective Na ions transport at the ...

Metal halide perovskites have demonstrated strong potential for optoelectronic applications. Particularly, two-dimensional (2D) perovskites have emerged to be promising materials due to their tunable properties and superior stability compared to their three-dimensional counterparts. For high device performance, 2D perovskites need a vertical crystallographic orientation with respect to the electrodes to achieve efficient charge transport. However, the vertical orientation is difficult to achieve with various compositions due to a lack of understanding of the thin film nucleation and growth processes. Here we report a general crystallization mechanism for 2D perovskites, where solvent evaporation and crystal growth compete to influence the level of supersaturation and a low supersaturation is necessary to crystallize vertically oriented thin films starting from nucleation at the liquid–air interface. Factors influencing the supersaturation and crystallization dynamics, such as choices of organic spacers, s...

Most of the electron transport layers (ETLs) used in inverted perovskite solar cells (PSCs) are fullerene derivatives, which are relatively expensive due to the complex synthesis process. Here we report coenzyme Q10, composed of quinone as the acceptor group and an alkyl chain as the donor group, which can be used as a low cost ETL alternative in inverted PSCs. The energy level alignments, carrier transport and recombination dynamics were systematically studied in comparison with the benchmark PC61BM. By optimizing the device structure and thickness of the ETL, the device with Q10 exhibits a comparable power conversion efficiency to the PC61BM device under the standard irradiation conditions. The carrier transport and recombination processes were further evaluated through steady state and time-resolved photoluminescence spectroscopy, space-charge-limited current, and Mott–Schottky measurements. An accelerated carrier injection ability and a passivated interface defect density between the perovskite and Q10 ETL were observed. Charge density difference from DFT calculations also determined that the band alignment of Q10 promoted easier charge transport from the perovskite. Moreover, the long alkyl chain of the Q10 molecule endows it with excellent hydrophobic properties, which largely improves the water-resistance capability of the Q10 ETL. This work highlights the great potential of Q10 as a cheap alternative for the most popular PC61BM ETL for inverted PSCs.

Metal halide perovskite materials have drawn worldwide attention for application in a variety of optoelectronic devices, especially in the emerging photovoltaic devices. In recent years, remarkable progress has been achieved in the device performance and stability. The optoelectronic properties of metal halide perovskites can be further tuned by ion doping. Herein, a comprehensive review of the incorporation of alkali metal ions (Li+, Na+, K+ and Rb+) in emerging perovskite solar cells for a longer carrier lifetime, lower interfacial defect density, faster charge transfer, no hysteresis, higher stability and higher power conversion efficiency is presented. The detailed mechanism behind these beneficial effects has been discussed in terms of electronic properties, film morphology, energy level alignment, carrier recombination dynamics and stability. On the basis of these latest advances and breakthroughs in alkali ion doped perovskite thin films, future research directions and prospects are also discussed, which include further understanding of the underlying photophysical mechanism and extension to other optoelectronic devices where a longer carrier lifetime and lower trap density are needed.

We studied livestock abortion and various associated risk factors in the Ili region of northwest China. Livestock abortion prevalence was estimated and correlated with infections (Brucellosis, Salmonellosis, Mycoplasma and Chlamydia seropositivity) and management (farming type and contact with other herds/flocks) risk factors. The prevalence of cow and sheep abortion induced by Brucella was 76.8% (PPMycoplasma caused an estimated 15.5% (P=0.025) and 17.6% (PP=0.001, sheep PP=0.007, sheep P=0.003), brucellosis positivity (cow PPMycoplasma positivity (cow P=0.031, sheep PMycoplasma in X county was cow 3.4%, sheep 7.9%; in H county was cow 5.3%, sheep 9.9%; and in Q county was cow 2.1%, sheep 4.3%. A total of 54 samples, including aborted cow (22), sheep (30) fetuses and milk samples (2), were identified as Brucella melitensis (B. melitensis) positive. A total of 38 Brucella were isolated from 16 aborted cow, 20 sheep fetuses and 2 milk samples. All of these isolates were identified, and confirmed, as B. melitensis. A phylogenetic tree showed that the Brucella isolates closely matched the B. melitensis biovar 3 isolated in Inner Mongolia, China, and B. melitensis isolated from Norway and India. These results suggest that B. melitensis biovar 3 is the main pathogen responsible for cow and sheep abortion and also pose a human health risk. Additionally, livestock reproduction can also be influenced by Mycoplasma infection and managerial factors (farming type and contact with other herds/flocks), especially in remote areas.

Aerofloats, such as aniline aerofloat ((C

Solution-processed TiO2 and other metal-oxide electron-transporting layers (ETLs) for perovskite solar cells commonly require high-temperature annealing (>450 °C), causing the underlying indium-tin...

Photoreduction of [PtCl6]2− over hexagonal ZnIn2S4 led to the formation of surface deposited small PtS nanoparticles with a size of ca. 3 nm. The resultant PtS/ZnIn2S4 nanocomposites were fully characterized and their performance for photocatalytic splitting of thiols to produce disulfides and hydrogen was investigated. It was found that PtS significantly promoted the photocatalytic performance for thiols splitting to produce disulfides and quantitative hydrogen over ZnIn2S4 under visible light and no over-oxidized products of thiols were produced. An optimum performance was observed over 0.5 wt% PtS/ZnIn2S4, with a complete transformation of thiols to disulfides in 6 h. PtS/ZnIn2S4 nanocomposite is stable during the photocatalytic reaction and can be easily separated for recycling. The photocatalytic thiols splitting over PtS/ZnIn2S4 is an efficient and cost effective strategy to produce disulfides, which exhibits 100% atom economy since hydrogen is generated concomitantly. This study demonstrates that the coupling of water reduction with organics oxidation over semiconductor-based photocatalysts may find great potentials in organic syntheses.

[EN] Using the open N,N'-chelating sites of MOF-253 (Al(OH)(dcbpy), dcbpy = 2,2'-bipyridine-5,5'-dicarboxylic acid) to coordinate with Re(I), a linker anchored Re complex MOF-253-Re(CO)(3)Cl active for photocatalytic CO2 reduction was obtained. Unlike the homogeneous bipyridine containing Re complexes which produce CO during photocatalytic CO2 reduction, formate was obtained as the main CO, reduction product over the as-obtained MOF-253-Re(CO)(3)Cl. The linker anchored MOF-253-Re(CO)(3)Cl showed superior photocatalytic performance compared to its homogeneous counterpart since the usual formation of the bimolecular Re intermediate leading to the deactivation of the homogeneous Re complex was significantly inhibited in the MOF supported Re complex. To enhance its light absorption, a linker anchored Ru sensitizer was simultaneously constructed in MOF-253-Re(CO)(3)Cl (Ru-MOF-253-Re). The total TON (TON is defined as mole of the evolved H-2, CO, and HCOO- over per amount of Rhenium) for CO2 reduction (28.8 in 4 h) over the as-obtained Ru-MOF-253-Re system is comparable or even superior to most already reported Re carbonyl complexes featuring bpy ligands and the Ru-Re bimetallic supramolecular systems constructed via the covalent bond under similar reaction conditions. The enhanced photocatalytic CO2 reduction over the Ru-MOF-253-Re can be ascribed to the improved visible light absorption and the existence of an efficient photoinduced charge transfer from Ru sensitizer to Re catalytic center, as evidenced from the transient absorption studies. The use of MOF-253 as a metalloligand and support to assemble the Ru-Re system as well as a mediator to promote the charge transfer from Ru sensitizer to Re catalytic center resembles the construction of Ru-Re supramolecular structures using covalent bonds, but is more facile in preparation and provides more flexibility. This study demonstrates the possibility of using MOFs with open coordination sites as a platform for the construction of a stable multifunctional hybrid system for artificial photosynthesis., This work was supported by 973 Program (2014CB239303) and NSFC (U1705251). Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa and CTQ2015-69153-CO2-1-R) is also gratefully acknowledged. Z.L. and J.A. also acknowledge the Award Program for Minjiang Scholar Professorship and the Universitat Politecnica de Valencia, respectively, for financial support.

Polycrystalline samples of CoAsSb were prepared by annealing a stoichiometric mixture of the elements at 1073 K for 2 weeks. Synchrotron powder X-ray diffraction refinement indicated that CoAsSb adopts arsenopyrite-type structure with space group P21/c. Sb vacancies were observed by both elemental and structural analysis, which indicate CoAsSb0.883 composition. CoAsSb was thermally stable up to 1073 K without structure change but decomposed at 1168 K. Thermoelectric properties were measured from 300 to 1000 K on a dense pellet. Electrical resistivity measurements revealed that CoAsSb is a narrow-band-gap semiconductor. The negative Seebeck coefficient indicated that CoAsSb is an n-type semiconductor, with the maximum value of −132 μV/K at 450 K. The overall thermal conductivity is between 2.9 and 6.0 W/(m K) in the temperature range 300–1000 K, and the maximum value of figure of merit, zT, reaches 0.13 at 750 K. First-principles calculations of the electrical resistivity and Seebeck coefficient confirmed ...

In light of low atomic mass, three types of experimentally synthetized borophene including β12, χ3 and striped t-sheet have been predicted to be promising anode materials for lithium-ion batteries (LIBs) with extremely high capacity. However, the rate performances of β12 and χ3 are quite poor with high diffusion barrier of 0.66–0.81 eV on β12 and 0.60–0.85 eV on χ3 in contrast with that in t-sheet (typically

Co9S8 can catalyze polysulfides conversion in Lithium sulfur batteries (LSBs) owing to its metallic nature and rich catalytic sites. However, its catalytic activity and chemical adsorption is not strong enough to suppress the shuttle effect of Lithium polysulfides (LiPS) under high sulfur loading. Herein, Phosphorous (P)-doped Co9S8 nanoparticle was synthesized and embedded into 3D Spongy carbon (SC) sheets as electrochemical catalyst for LSBs. Our Density functional theory (DFT) calculations and experimental results revealed that moderate P doping can modulate the electronic structure of Co9S8 and simultaneously improve its interaction with LiPS and promote LiPS conversion. When P-doped Co9S8 nanoparticles are in situ formed and homogeneously distributed on 3D spongy carbon sheet matrix, the resulting P-Co9S8@SC can ensure good exposure of their adsorption and catalytic sites. As a result, the LSB based on an optimized P-Co9S8@SC modified polypropylene separator exhibited excellent cycling stability (capacity decay of 0.05% per cycle over 900 cycles at 1 C) and high areal capacity (4.38 mAh cm−2 at 5.6 mg cm−2 sulfur loading at 0.1 C). Our work demonstrates that moderate heteroatom doping is a promising strategy to develop effective polysulfides catalysis.

With the aim of developing renewable energy based processes, researchers are paying increasing interest to light induced organic transformations. Metal-organic frameworks (MOFs), a class of micro-/mesoporous hybrid materials, are recently emerging as a new type of photoactive materials for organic syntheses due to their unique structural characteristics. In this Review, we summarized the recent applications of MOFs as photocatalysts for light induced organic transformations, including (1) oxidation of alcohols, amines, alkene, alkanes and sulfides; (2) hydroxylation of aromatic compounds like benzene; (3) activation of the C-H bonds to construct new C-C or C-X bonds; (4) atom-transfer radical polymerization (ATRP). This Review starts with general background information of using MOFs in photocatalysis, followed by a description of light induced organic transformations promoted by photoactive inorganic nodes and photocatalytic active ligands in MOFs, respectively. Thereafter, the use of MOFs as multifunctional catalysts for light induced organic transformations via an efficient merge of the metal/ligand/guest based catalysis where the photocatalytic activity of MOFs plays a key role are discussed. Finally, the limitations, challenges and the future perspective of the application of MOFs for light induced organic transformations were addressed. The objective of this Review is to serve as a starting point for other researchers to get into this largely unexplored field. It is also our goal to stimulate intensive research in this field for rational designing of MOF materials to overcome their current limitations in photocatalysis, which can lead to more creative visible-light-induced organic transformations.

In order to realize high-throughput roll-to-roll manufacturing of flexible perovskite solar cells, low-temperature processing of all device components must be realized. However, the most commonly used electron transporting layer in high-performance perovskite solar cells is based on TiO2 thin films processed at high temperature (>450 °C). Here, we demonstrate room temperature solution processing of the TiOx layer that performs as well as the high temperature TiO2 layer in perovskite solar cells, as evidenced by a champion solar cell efficiency of 16.3%. Using optical spectroscopy, electrical measurements, and X-ray diffraction, we show that the room-temperature processed TiOx is amorphous with organic residues, and yet its optical and electrical properties are on par with the high-temperature TiO2. Flexible perovskite solar cells that employ a room-temperature TiOx layer with a power conversion efficiency of 14.3% are demonstrated.

Iron is a fundamental element required by most organisms, including

Most existing face key point detection algorithms only consider improving the generalization performance of the model, while ignoring the model efficiency. However, models with good generalization performance usually contain a large number of parameters, which hinders the deployment of face key point detection algorithms on devices with limited resources. In order to overcome this problem, a Fast and Accurate Face Alignment Algorithm is proposed in this paper. First, a teacher network that stacks multiple hourglass modules is designed. Its model structure is robust to meet the positioning accuracy requirements in actual use. Then, a lightweight student network is designed, which has fewer model parameters and faster feature extraction speed, which meets the speed requirements in practical use. Finally, through the knowledge distillation strategy, the knowledge of the teacher network is transferred to the student network, which makes the student network take into account both the model inference speed and the key point positioning accuracy.

MOF-253 (Al(OH)(dcbpy), dcbpy = 2,2'-bipyridine-5,5'-dicarboxylic acid) obtained via a microwave-assisted synthesis was used for the construction of a supported Ru complex containing dcbpy (MOF-253-Ru(dcbpy)

With the successful launch of China’s GF series satellites, it is more important to study the image data quality, the adaptability of processing method and information extraction method. The panchromatic and multi-spectral data which is based on the GF-2 images data of Chinese sub-meter high-resolution remote sensing satellite is fused by PCA, Pansharp, Gram-Schmidt and NNDiffuse fusion. Then, the quality of the fusion images were evaluated subjectively and objectively. In order to evaluate the applicability of different classification algorithms to the classification, the object-oriented classification algorithm which is based on machine learning algorithm, such as KNN, SVM and Random Trees were used to classify the different GF-2 fusion images. The results showed that: (1) The best visual effect of GF-2 fusion image was the Pansharp fusion image; The quantitative evaluation results showed that the brightness and information retention of Gram-Schmidt fusion image was the best, while the Pansharp fusion image had the highest correlation with the original multi-spectral image; the NNDiffuse fusion image had the highest clarity, and the PCA fusion image quantitative evaluation effect was the worst; (2) According to the applicability analysis of the fusion images based on different classification algorithms with features information extraction, it could be seen that the NNDiffuse fusion method was used for the fusion of GF-2 image data, and the classification of the fusion images was more suitable by using KNN or Random Trees classification algorithm. RESUMEN Con el lanzamiento exitoso de los satélites de la serie GF de China es más importante estudiar la calidad de los datos de imagen, la adaptabilidad del método de procesamiento y el método de extracción de información. Los datos pancromáticos y multiespectrales que se basan en los datos de imágenes GF-2 del satélite de teleobservación de alta resolución en el submetro chino, se fusionaron mediante PCA, Pansharp, Gram-Schmidt y NNDiffuse. Luego, la calidad de las imágenes de fusión se evaluó de manera subjetiva y objetiva. Para evaluar la aplicabilidad de diferentes algoritmos de clasificación, se utilizó el algoritmo de clasificación orientado a objetos basado en el aprendizaje automático, como KNN, SVM y árboles aleatorios para clasificar las diferentes imágenes de fusión de GF-2. Los resultados mostraron que: (1) El mejor efecto visual de la imagen de fusión GF-2 fue la imagen de fusión Pansharp; los resultados de la evaluación cuantitativa mostraron que el brillo y la retención de información de la imagen de fusión Gram-Schmidt fueron los mejores, mientras que la imagen de fusión Pansharp tuvo la mayor correlación con la imagen multiespectral original; la imagen de fusión NNDiffuse tuvo la mayor claridad, y el efecto de evaluación cuantitativa de la imagen de fusión PCA fue el peor; (2) De acuerdo con el análisis de aplicabilidad de las imágenes de fusión basadas en diferentes algoritmos de clasificación con características de extracción de información, se pudo ver que se usó el método de fusión NNDiffuse para la fusión de datos de imágenes GF-2, y la clasificación de las imágenes de fusión fue más apropiada utilizando el algoritmo de clasificación KNN o Random Trees.

The commercialization process of metal hybrid perovskite solar cells (PSCs) is hindered by the poor quality of perovskite films, imperfect carrier extraction, and inferior stability. Organic or inorganic molecules have been widely used to overcome these limitations. Herein, 5-(ethylthio)-1H-tetrazole (ETT) is applied for the deposition of perovskite films with high crystallinity and smooth surface. Due to the interaction between the lone pair electrons of tetrazole and Pb2+, the surface defects of perovskite films were passivated, thus leading to facilitated charge transport and inhibited carrier recombination. The improved crystallinity and defect passivation enabled a power conversion efficiency over 20% in the ETT-modified inverted MAPbI3 PSC device, along with notably enhanced moisture stability. Our work provides a feasible strategy for the crystallization modulation and humidity stability enhancement of PSCs.

In highly efficient halide perovskite solar cells (PSCs), nickel oxide (NiOx) have been widely used as an inorganic hole transport layer (HTL). However, the solution-processed NiOx films always have pinholes, along with inferior contact with perovskite layer. Herein, a surfactant of hexadecylbenzene (HAB) was applied to improve the hole extraction from perovskite to NiOx HTL. With the modification of HAB, a high quality perovskite layer was obtained. Due to the enhanced hole extraction, the HAB modified device showed a higher short-circuit current density (JSc ) and a power conversion efficiency of 17.11%. Therefore, this work offers a novel strategy in interfacial engineering for high-efficiency PSCs.

Lithium-sulfur batteries (LSBs) have gained intense research enthusiasm due to their high energy density. Nevertheless, the ‘shuttle effect’ of soluble polysulfide (a discharge product) reduces their cycling stability and capacity, thus restricting their practical application. To tackle this challenging issue, we herein report a sulfonated covalent organic framework modified separator (SCOF-Celgard) that alleviates the shuttling of polysulfide anions and accelerates the migration of Li+ ions. Specifically, the negatively charged sulfonate can inhibit the same charged polysulfide anion through electrostatic repulsion, thereby improving the cycle stability of the battery and preventing the Li-anode from being corroded. Meanwhile, the sulfonate groups may facilitate the positively charged lithium ions to pass through the separator. Consequently, the battery assembled with the SCOF-Celgard separator exhibits an 81.1% capacity retention after 120 cycles at 0.5 C, which is far superior to that (55.7%) of the battery with a Celgard separator. It has a low capacity degradation of 0.067% per cycle after 600 cycles at 1 C, and a high discharge capacity (576 mAh g−1) even at 2 C. Our work proves that the modification of a separator with a SCOF is a viable and effective route for enhancing the electrochemical performance of a LSB.

Anion exchange membranes (AEMs) are an important component in anion exchange membrane fuel cells, and their side chain structures have a significant impact on membrane performance. Here, we construct a series of poly(phenylene oxide) (PPO)-based AEMs with varied side chain structures and investigate the effects of alkyl or alkoxyl extenders (or “tail” of the cation) and spacers (or the link between backbone and cation head group) on AEM performance. Our investigations demonstrate that the simultaneous introduction of alkoxyl extender and spacer can significantly improve water absorption and ion conductivity of membrane; this is attributed to the good hydrophilicity of alkoxyl group and flexibility of spacer that benefit the formation hydrophilic domains. At an IEC (ion exchange capacity) of 1.13 mmol/g, the AEM containing both spacer and alkoxyl extender exhibits a hydroxide conductivity of 87.3 mS/cm (80 °C), which is much higher than that of other spacer-containing membranes at similar IECs. The H2/O2 single cell constructed with this membrane exhibits a good peak power density of 292 mW/cm2 at 60 °C. In addition, the steric hindrance of the extender gives rise to higher alkali stability of the AEM than that of the membrane which does not have the extender. Our work provides a meaningful direction of side chain design which can effectively improve conductivity and alkaline stability of AEMs.

The utilization of solar energy for CO2 conversion to produce valuable chemicals or fuels is extremely appealing since it can simultaneously reduce the greenhouse effect and relieve the energy shortage pressure. In addition to the commonly used semiconductor-based photocatalysts, metal–organic frameworks (MOFs), a class of micro-mesoporous hybrid materials, are recently emerging as new types of photoactive materials for CO2 reduction due to their excellent adsorption capability toward CO2 and unique structural characteristics. In this review, we summarized the recent applications of MOFs for photocatalytic CO2 reduction, in which MOFs either act directly as the photocatalysts for CO2 reduction or as components in a hybrid photocatalytic system to promote CO2 reduction. This review starts with a brief introduction of the background of photocatalytic CO2 reduction, followed by a summarization of CO2 reduction catalyzed by photoactive ligands and metal nodes in MOFs, respectively. Thereafter, the construction of hybrid photocatalytic systems in which MOFs play a role in promoting photocatalytic CO2 reduction is described. Finally, the limitations, challenges and future prospects of the application of MOFs to CO2 reduction are addressed. We hope that this review not only can serve as a starting point to get into this largely unexplored field but can also stimulate intensive research on the rational design and development of more creative MOF systems for light induced CO2 conversion, which is a green and sustainable strategy for CO2 utilization.

Development of inorganic metal halide perovskites solar cells (PSCs) has been hampered by the inherent phase instability of inorganic perovskites. Herein, an ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4) is proposed to stabilize the CsPbI2Br phase and reduce the surface defect density. From experimental analyzes and density functional theory calculations, the BMIMBF4 interlayer could reduce the energy loss and stabilize the cubic -phase of CsPbI2Br. The interaction between BMIMBF4 and CsPbI2Br could improve the perovskite film quality and the interfacial charge transport. Accordingly, the BMIMBF4-modified device enables a 37.18% and 18.89% improvement in the power conversion efficiency and open-circuit voltage compared to the control CsPbI2Br device, along with an 86.9% retaining of its initial performance over 1000 h storage in N2 atmosphere, while the control device drops to zero in 200 h. The work provides a novel cogitation for the defect passivation and energy loss reduction to improve both the stability and efficiency of inorganic perovskite solar cells.

Hybrid perovskite solar cells (PSCs) have come into prominence as a potential alternative to crystalline silicon solar cells due to their outstanding photovoltaic performance and the simple manufacturing process. Over the past few years, the performance has greatly benefited from the emergence of advanced fabrication technologies capable of producing high quality perovskite films. The transforming process from precursor to perovskite film directly influences the film quality by controlling the nucleation and crystal growth. In particular, the coordination of electron-rich atoms in solvent or additives with Pb ions in perovskite precursor has been widely used to modulate the crystal growth to obtain compact and dense perovskite film with fewer defects. Here, a systematic review is presented to describe the effect of coordination interaction on perovskite crystallization process, defects passivation, hysteresis behavior and long-term stability for efficient perovskite thin film and related photovoltaics. Functional additives with carbonyl-, acyl- and cyano- group bearing lone electron pairs have been widely adopted to coordinate with PbI2 to retard crystallization and obtain a high-quality perovskite film. Meanwhile, these additives can modify the surface or grain boundary of as-formed perovskite film to passivate defects, mitigate hysteresis and prevent the moisture permeation to prolong the device lifetime. The coordination interaction provides a feasible strategy to improve the perovskite film quality, which is crucial to increase the efficiency and longevity of PSCs and other related optoelectronic devices towards future upscaling and commercialization.

Perovskite solar cells (PSCs) have been widely investigated in the past decade with a certificated record efficiency up to 25.2%, which is comparable to the inorganic thin-film and crystalline silicon photovoltaics. Further improving the device photovoltaic performance and long-term stability has been pursued to impel commercial application. Ionic liquids, an old class of compounds that contain large asymmetric organic cations coupled with organic or inorganic anions, have been used in high-performance PSC devices with enhanced efficiency and stability due to their unique physicochemical properties. Herein, the recent progress of ionic liquids engineering in PSCs is comprehensively reviewed and the potential mechanisms on device performance and stability are illustrated. Specifically, the main beneficial effects of ionic liquids including crystallization process modulation, energy level alignment, independent charge extraction layer or dopant, enhancing the moisture and thermal stability are summarized. Future prospects towards the realization of ultra-stable and efficient PSCs with ionic liquid engineering are also discussed and presented.

Crystal orientation of perovskite film and interface modification plays an important role in the efficient operation and stability of perovskite solar cells (PSC). Herein, a high quality perovskite film with large grain size, high crystallinity and preferred crystal orientation on (100) plane is deposited on an aqueous solvent (H2O and DMF) pretreated nickel oxide (NiOx) substrate (HDP). The aqueous solvent treatment increases the wettability and conductivity of NiOx layer during perovskite growth. Steady-state and time-resolved photoluminescences reveals a significantly increased charge extraction efficiency in the HDP perovskite films. In addition, the HDP devices exhibit impressively improved photovoltaic performance as well as enhanced long-term stability under high moisture, UV irradiation and thermal stress. Therefore, our work provides a versatile strategy to introduce preferred orientation and interfacial modification to enhance the crystal quality and stability of halide perovskite thin films and related optoelectronic devices.