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We propose a simple strategy to fabricate a composite material consisting of amino-functionalized carbon nanotubes (NCNTs) grafted with a covalently bonded Ni(II)-based covalent organic framework (COF) for electrocatalytic water splitting. The resulting electrocatalyst demonstrates remarkable catalytic efficiency in both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) under alkaline conditions. [ABSTRACT FROM AUTHOR]

Support materials such as activated carbon are essential for electrochemical heterogeneous reactions, providing a stable matrix for metal catalysts and actively influencing the catalyst's properties and effectiveness. Although various effective carbon supports have been commercially developed, corrosion and catalyst degradation are still inevitable under high current density catalysis, for instance, during the harsh alkaline water electrolysis process. Here, we report the synthesis of a new type of metallic glass (MG) support through the deployment of an amorphous alloy with tunable Pt loading mass (Fe70−xCo10Ni10Zr10Ptx, x = 1, 3, 5). In addition to the advantages of high specific surface areas and enhanced chemical stability, X-ray absorption spectroscopy and theoretical investigations suggest that the MG support could modulate the electronic structure of Pt active sites through strong metal–support interaction, leading to the enhanced water dissociation kinetics. When compared with those previously reported carbon-supported or pure Pt catalysts, the MG-supported catalysts exhibit remarkably high activities towards hydrogen evolution, which only requires an overpotential of 102 mV at the current density of 1000 mA cm−2 with a Faraday efficiency close to 100%. This allows the current density to be increased to 500 mA cm−2 during the stability test without corrosion and degradation. We argue that the earth-abundant elements-based MG support could be an alternative for metal catalysts that can withstand the physical and chemical corrosion encountered during harsh catalytic reactions. [ABSTRACT FROM AUTHOR]

The volume and composition of airway surface liquid (ASL) is regulated by liquid secretion and absorption across airway epithelia, controlling the pH, solute concentration, and biophysical properties of ASL in health and disease. Here, we developed a method integrating explanted tracheal tissue with a micro-machined device (referred to as "ex vivo trachea-chip") to study the dynamic properties of ASL volume regulation. The ex vivo trachea-chip allows real-time measurement of ASL transport (Jv) with intact airway anatomic structures, environmental control, high-resolution, and enhanced experimental throughput. Applying this technology to freshly excised tissue we observed ASL absorption under basal conditions. The apical application of amiloride, an inhibitor of airway epithelial sodium channels (ENaC), reduced airway liquid absorption. Furthermore, the basolateral addition of NPPB, a Cl-channel inhibitor, reduced the basal rate of ASL absorption, implicating a role for basolateral Cl- channels in ASL volume regulation. When tissues were treated with apical amiloride and basolateral methacholine, a cholinergic agonist that stimulates secretion from airway submucosal glands, the net airway surface liquid production shifted from absorption to secretion. This ex vivo trachea-chip provides a new tool to investigate ASL transport dynamics in pulmonary disease states and may aid the development of new therapies targeting ASL regulation. [ABSTRACT FROM AUTHOR]

The critical step of a dye-sensitized photoelectrochemical cell (DSPEC) is water oxidation. The photoanodes suffer rapid surface carrier recombination due to slow water oxidation kinetics and this results in low solar conversion efficiency and poor stability. Here, we design a novel sensitization–oxidation photo-anode, where the [Ru(4,4′-PO3H2-bpy)(bpy)2]2+ (RuP2+, bpy = 2,2′-bipyridine) chromophore and [Ru(bda)(pic)2] (pic = picoline, bda = 2,2′-bipyridine-6,6′-dicarboxylate) water oxidation catalyst (WOC) are immobilized separately on the surface of a mesoporous semiconductor thin film. The electrode creates a mobile and strong Br3− oxidant generated by the dye-sensitized electrode, which initiates water oxidation at a remote catalytic site. Under 100 mW cm−2 illumination in pH 4.65 in 0.1 M acetate buffer solution, the photoanode could perform a stable photoelectrochemical water oxidation for 6 hours with a photocurrent density of around 0.25 mA cm−2. This dual electrode could open a new door by utilizing an electron transfer mediator to design highly stable photoelectrochemical cells. [ABSTRACT FROM AUTHOR]

Upconversion (UC) nanoparticles (NPs) have gained significant attention in many fields, such as super resolution nanoscopy and background-free bioimaging. UC efficiency is one of the most important parameters in these practical applications. However, enhancing the UC efficiency of core-only NPs synthesized in a single step, without the need for additional post-processing, has remained a great challenge. In this study, we propose an effective strategy for significantly enhancing the UC intensity by constructing local energy clusters within the lanthanide-doped fluoride NPs. By introducing local energy clusters within the NaGdF4 crystal lattice, the optimal Er3+, Ho3+ and Tm3+ doping concentrations were increased to 8 mol%, 8 mol%, and 2 mol%, respectively. The UC intensity of the 20Yb/8Er/20Ca:NaGdF4 NPs is approximately 54.3 times higher than that of typical 20Yb/2Er:NaGdF4 NPs, which is attributed to the increased energy transfer efficiency from Yb3+ to Er3+ and the reduced energy loss caused by surface vibrations. Moreover, with the formation of energy clusters within the crystal lattice, the temperature-dependent UC intensity behavior shifted from a negative thermal quenching effect to a positive thermal quenching effect, which results in enhanced temperature sensing performance. The violet UC from Tm3+ activators was significantly enhanced through the energy clusters, which facilitates the noticeable inter-particle energy migration UC of Tb3+ ions. Overall, our study presents a novel approach to significantly enhance the optimal doping concentrations of lanthanide activators and the UC intensities of NPs. These findings open up exciting opportunities for the development of high-performance UCNPs with improved applications in various fields. [ABSTRACT FROM AUTHOR]

Compared with commercial bulk scintillators and halide perovskites, lanthanide-doped fluoride nanoscintillators (NSs) exhibit high photochemical stability, low bio-toxicity and tunable emissions. However, the widely employed hosts, such as NaGdF4, NaLuF4 and NaYF4, need many expensive rare earth salts and time-consuming reaction processes. In this work, lanthanide-doped NaBiF4 NSs were prepared by a facile rapid room-temperature reaction method. The obtained NSs present a hollow structure, strong scintillation intensity and ultra-weak afterglow. The scintillation intensity was enhanced by incorporating Gd3+ ions, but it was decreased after codoping with Ho3+ or Er3+ ions. By employing a NaBiF4:15Tb/10Gd NS integrated thin film as a nanoscintillator screen, a high spatial resolution of 12.5 lp mm−1 was achieved. Our results could promote the exploration of new kinds of NSs with low cost, high production and superior performances. [ABSTRACT FROM AUTHOR]

Tb3+-doped oxyfluoride glass scintillators have aroused significant attention due to their ability to absorb high energy radiation and convert the energy to visible light. Herein, a series of Tb3+-doped Gd-based oxyfluoride glasses (SiBNaBaGd–xTb) were synthesized and their superior optical and scintillation properties were investigated. These oxyfluoride glasses have high transmittance (higher than 88% @542 nm) and emit bright green light. The highest internal quantum efficiency reaches 75.3%. The integral intensity of X-ray excited luminescence of SiBNaBaGd–5.0Tb is 250% that of commercial scintillator Bi4Ge3O12. Response change during irradiation is relatively insignificant. The spatial resolution of SiBNaBaGd–5.0Tb for X-ray imaging is 20 lp mm−1. These results indicate that the SiBNaBaGd–5.0Tb glass might be a potential candidate scintillator for X-ray imaging. [ABSTRACT FROM AUTHOR]

Dental caries of permanent teeth is a common public health concern and has the second-highest incidence among global diseases. The exopolysaccharides (EPS) synthesized by Streptococcus mutans (S. mutans) are the principal virulence factor for cariogenic etiology. We previously discovered that an endogenous antisense vicR RNA (ASvicR) could significantly inhibit EPS synthesis in S. mutans and reduce its cariogenicity. However, ASvicR cannot be directly applied in the oral environment. An appropriate vector is of great need to protect ASvicR from being degraded by nucleases for effective gene delivery to S. mutans. Functionally modified starches shed light on this field because of their excellent biocompatibility and biodegradability. In this study, a biocompatible and biodegradable spermine-starch nanocomposite (SSN) was constructed for ASvicR delivery. Starch was cationically functionalized by grafting endogenous spermine to closely bind with the recombinant ASvicR plasmid. The SSN not only protected the recombinant ASvicR plasmid from DNase I but also achieved highly efficient gene transformation to S. mutans via the hydrolysis of α-amylase in the saliva. In addition, SSN-ASvicR was shown to endow ASvicR with an increasing transformation efficiency approximately four times that of the naked ASvicR plasmid, as well as allowing for targeting specificity to the transcription of the vicR gene and the suppression of biofilm organization via EPS digestion. In particular, SSN-ASvicR nanoparticles exhibited excellent biological safety and maintained oral microbiota homeostasis in vivo. The SSN can be prepared in a ready-to-use formulation for targeting cariogenic bacteria, thus demonstrating important prospects in the prevention of dental caries. [ABSTRACT FROM AUTHOR]

Considering the two limitations of the biocompatibility of metal–organic-frameworks (MOFs) and the low utilization of lignin biomass, herein, we review the interaction between lignin macromolecules and MOFs to promote their high-end applications and sustainability. Firstly, lignin and lignin derivatives can coordinate with metal ions to form bio-based MOFs due to their biocompatibility and surface-rich functional groups, which solves the difficulty of applying the original MOFs in biomedicine and other fields. We introduce the structure, coordination process, and advantages of applying bio-based MOFs in detail and discuss the problem that powdered MOFs are easily blocked and difficult to be separated and recovered. Secondly, MOFs can be used as catalysts to facilitate the conversion of lignin to liquid fuels and fine chemicals, thereby alleviating the energy shortage. We discuss the mechanism and products from the redox depolymerization of lignin using MOFs and their derivatives. The opportunities and challenges encountered in bio-based MOFs and selective cleavage of lignin are discussed based on several perspectives. It is hoped that this study can provide good theoretical guidance for the synthesis of bio-based MOFs and the conversion of lignin. [ABSTRACT FROM AUTHOR]

Here, a "chemical unit co-substitution" method is used to improve the near-infrared (NIR) emission of phosphors, using [Zn2+–Ge4+] to co-substitute [Ga3+–Ga3+] sites to reduce crystal field splitting to affect the structure of gallium oxide. A series of broadband NIR phosphors are synthesized by a high-temperature solid-phase method, and their phase structures, crystal structures, morphologies, diffuse reflectance spectra, and luminescence lifetimes are investigated. The Ga1.68(Zn–Ge)0.3O3:0.02Cr3+ (GZGOC) phosphor exhibits NIR wide-band emission, with a peak wavelength of 766 nm and a half-width of 138 nm. Meanwhile, the quantum yield of photoluminescence can reach 81.2%. The phosphor has good thermal stability. When the temperature reaches 373 K, its emission intensity still remains at 73.4% of that at room temperature. A 460 nm LED chip and this phosphor are used to fabricate a phosphor-converted light emitting diode (pc-LED) device which can be used as a NIR light source. All these results show the application potential of the as-prepared phosphor in NIR imaging. [ABSTRACT FROM AUTHOR]

Photoreactive coordination polymers are particularly important media for the implementation of highly-selective photoreactions and creation of photoresponsive intelligent materials and devices. Herein, a two-dimensional (2D) photoreactive coordination polymer, formulated as [Cd(pha)(3,3′-bpe)]n (1) was prepared through the hydrothermal reaction between Cd(NO3)2·4H2O, phthalic acid (H2pha) and 1,2-bis(3-pyridyl)ethylene (3,3′-bpe). Upon exposure to 365 nm UV light, the 1H NMR spectroscopy and single crystal X-ray diffraction analysis results indicated that 1 can undergo a [2 + 2] photocycloaddition reaction and thus form a new coordination polymer [Cd(pha)(3,3′-tpcb)0.5]n (1a) through single-crystal to single-crystal (SCSC) transformation. Accompanied by the SCSC photoreaction, the 2D sql net of 1 converted into a 2D binodal network of 1a with the rare (324·627)(326272) topology. The SCSC transformation from 1 to 1a also exhibits an interesting photocontrolled fluorescence. The unique photoinduced structural change and fluorescence quenching of 1 makes it a potential intelligent material for optical anti-counterfeiting, fluorescence sensors and other fields. [ABSTRACT FROM AUTHOR]

An efficient and stable CdS@MoS2 core@shell heterostructure was prepared by using a facile solvothermal approach. The MoS2@CdS heterostructure reveals efficient charge separation, giving rise to excellent performance on H2 generation from photocatalytic lactic acid decomposition. Thanks to the MoS2 shell protection, CdS corrosion was significantly prohibited, thus resulting in the long-term photocatalytic stability of the CdS@MoS2 heterostructure. The corresponding charge transfer properties and catalytic mechanism have been analyzed and discussed in detail. The present study provides a novel insight into the design of high performance and cost-effective photocatalysts. [ABSTRACT FROM AUTHOR]

Real-time in situ temperature sensing is of significance in the bio-medical field; however, the low relative temperature sensitivity Sr is one of the major obstacles in the development of nanothermometers. Herein, we provide an effective route that engineers the interfacial layer in a core/shell/shell nanostructure to enlarge the temperature-dependent luminescence intensity ratio (LIR) variations followed by an improved Sr. The CaF2 interlayer is employed to inhibit the interaction between the core and outer shell, and increase the interfacial phonon energy to enhance the negative thermal quenching effect (TQE) of Nd3+ ions in the outer shell and positive TQE of Er3+ ions in the core layer. Based on the temperature-dependent LIR variations of Er (650 nm) to Nd (800 nm), the maximum Sr of 10.01% K−1 and minimum Sr of % 2.56% K−1 are achieved. [ABSTRACT FROM AUTHOR]

Poly(ethylene glycol) (PEG)-based hydrogels as highly promising 3D cell scaffolds have been widely implemented in the field of tissue regrowth and regeneration, yet the functionalized PEG hydrogel providing dynamic, cell-instructive microenvironments is inherently difficult to obtain. Here, we have exploited the specificity of click reaction to develop a set of hydrogels based on 4-arm PEG tetraazide (4-arm-PEG-N3) and di-propargylated peptides (GRGDG and GRDGG) with tunable physicochemical properties applicable for 3D cell scaffolds. The azide groups of PEG were reacted with the alkynyl groups of peptides, catalyzed by copper to form triazole rings, thus generating a cross-linked hydrogel. The gelation time and mechanical strength of the hydrogels varied according to the PEG/peptide feed ratio. The resulting hydrogel exhibited a typical porous microstructure and suitable swelling behavior. The in vitro cytotoxicity test indicated that the resulting hydrogels did not cause apparent cytotoxicity against human corneal epithelial cells (HCECs). After co-incubation with HCECs, the density of RGD as well as peptide sequence in the hydrogels remarkably affected the cell attachment, spreadability, and proliferation. Additionally, the proposed hydrogel showed high ocular biocompatibility after being embedded subconjunctivally into rabbit eyes. Overall, these findings highlighted that the biofunctional hydrogels formed by PEG and RGD motifs via a controllable click reaction might be promising 3D cell scaffolds for corneal epithelial regeneration. [ABSTRACT FROM AUTHOR]

Alternative scintillating materials are of current interest for radiation detection in diverse high-energy applications, e.g., in X-ray imaging and high-energy physics. However, single crystals as the main material for scintillators hinder the preparation with large size, low cost, and diverse shape. Here, we offer an easy preparation procedure of Mn2+-activated aluminoborate glasses under air atmosphere by the traditional melt-quenching approach. These glass specimens exhibit broadband photoluminescence and radioluminescence under ultra-violet light and X-ray excitation, respectively. Moreover, the reduction of Mn3+ to Mn2+ leads to improved scintillating performance, favoring the preparation of Mn2+-doped scintillating glasses under air atmosphere. The energy transfer from Gd3+ to Mn2+ contributes to both photoluminescence and radioluminescence and the energy transfer efficiency reaches 96.4%. More notably, the integrated X-ray excited luminescence intensity from the optimal specimen is 42.2% that of the commercial Bi4Ge3O12 single crystal scintillator, offering great potential in X-ray detection and large area imaging. [ABSTRACT FROM AUTHOR]

Lead (Pb) is one of the most widespread and highly toxic heavy metals in the environment. The design and synthesis of adsorbent materials for the selective and efficient removal of Pb2+ from aqueous solution has received much attention. Herein, the ligand 4,4′-azoxydibenzoic acid with the O− group was elaborately selected to construct a novel Pr-based MOF for Pb2+ removal. The as-prepared MOF adsorbents with high stability exhibited ultra-high selectivity for Pb2+, even in the presence of various highly concentrated competitive ions (with the ratios from 1 : 5 to 1 : 50). Also, a high uptake capacity (560.26 mg g−1) can be achieved for the MOF material, due to the availability of sufficient adsorption sites. The strong electrostatic attraction and coordination interaction between the numerous active O− sites on MOF adsorbents and Pb2+ can account for the good adsorption performance for Pb2+, which was systematically verified by zeta potential, FT-IR and XPS studies. [ABSTRACT FROM AUTHOR]

A thermal quenching effect caused by the increased multi-phonon assisted non-radiative relaxation possibility greatly restricts the application of luminescent materials. Herein, a modified sol–gel method where the gels are achieved by an ultra-fast evaporation process is employed to prepare lanthanide doped Gd2Ti2O7 crystals, which leads to lattice contraction owing to the formation of vacancy defects. Upon increasing the temperature from 293 to 573 K, the red UC intensities of Er3+ and Ho3+ ions enhance about 5.6 and 9.6 times, respectively, which is attributed to the reduced energy migration from activators to vacancy defects at higher temperatures. These processes are fully reversible. Upon integrating the Gd2Ti2O7:Yb/Er crystals with a negative thermal quenching effect and the NaGdF4:Yb/Tm@NaYF4 nanocrystals with a positive thermal quenching effect, a high relative temperature sensitivity of 8.73% K−1 at 293 K is achieved. These crystals have potential applications not only in highly sensitive temperature sensing, but also in anti-counterfeiting with high security levels. [ABSTRACT FROM AUTHOR]

Al0.17V2O5(H2O)2·H2O (AlVO) and Ca0.23V2O5(H2O)·H2O (CaVO) are synthesized herein, and their Rietveld refinements reveal that they are composed of V–O–V layers, lamellar hydrated Al3+ or Ca2+ and dissociated water molecules. The preintercalation of metal ions into V2O5 leads to the elongation of V–O bonds, and all the V centers are unsaturated coordinated. The V–O–V bilayer in V2O5 is split into two discrete V–O–V monolayers with the (001) facet as the division plane. Meanwhile, the exposed V centers on the (001) surface are unsaturated with oxygen vacancies, which can facilitate the migration of Zn2+ along the (001) surface of AlVO with a lower energy barrier of 0.88 eV, as evidenced by density functional theory (DFT) simulations. AlVO shows a dominant pseudocapacitive behavior with excellent rate capability and outstanding cycling performance. It can deliver a high capacity of 441 mA h g−1 at 0.1 A g−1 with capacity retentions of 96.7% and 90.5% after 1000 and 2000 discharge/charge cycles at 5 A g−1, respectively, which are superior to that of CaVO. In addition, DFT calculations also reveal that the intercalation of Zn2+ on some sites in the interlayer channels of AlVO and CaVO is irreversible with very negative binding energies, leading to the accumulation of Zn2+ in AlVO and CaVO. Furthermore, ex situ characterization of AlVO and quasi-reversible change of the pH value during the 1st discharge/charge process indicate a co-(de)intercalation mechanism of H+ and Zn2+. The pH-induced V species and the accumulation of Zn2+ give rise to partial transformation of AlVO → Al3+-doped Zn3(OH)2V2O7·2H2O, which is also observed for CaVO. [ABSTRACT FROM AUTHOR]

Fluorescence intensity ratio-based temperature sensing with a self-referencing characteristic is highly demanded for reliable and accurate sensing. Lanthanide ions with thermally coupled levels have been widely used for ratiometric temperature sensing. However, these systems suffer from low relative temperature sensitivity and poor luminescence signal discriminability. Herein, the concept of indirectly thermally coupled levels is introduced and employed to actualize high performance temperature sensing. By means of the temperature-dependent phonon-assisted non-radiative relaxation, the 4I13/2 excited state (with infrared emission) of Er3+ can be indirectly thermally coupled with the 4S3/2 excited state (with visible emission) under 808 nm or 980 nm excitation. This is experimentally realized in specially designed NaErF4:10Yb@NaYF4 nanocrystals, and the corresponding ratiometric nanothermometer shows excellent luminescence thermal sensing performance with a maximum relative sensitivity value up to 3.76% K−1 at 295 K. [ABSTRACT FROM AUTHOR]

Herein, a brief structural design strategy is proposed to fabricate amorphous CoMo bimetallic oxyfluoride on graphite felt (CoMoOF/GF) for efficient hydrogen evolution reaction (HER). Porous and defective CoMoO/GF is employed as a structure-induced template to induce the formation of CoMoOF/GF with more rich defects and a larger pore structure via proper anodic treatment. Theoretical calculations reveal a synergistic catalytic effect stemming from the CoMo bimetallic components, endowing CoMoOF/GF with more favorable HER performance. The amorphous construction endows the catalyst with remarkable mass transfer ability and sufficient exposed atoms, enhancing the electrochemically active surface area (ECSA). CoMoOF/GF with structural advantages and the synergistic effect of bimetallic components displays a considerably low overpotential of 79 mV at η10 and a Tafel slope of 43.3 mV dec−1 for the HER in alkaline medium. Furthermore, excellent activity with an overpotential of 94 mV at η10 and a Tafel slope of 60.2 mV dec−1 is observed in acidic medium as well. Besides, long-term stability is achieved within CoMoOF/GF when operating at −200 mV for 100 h. [ABSTRACT FROM AUTHOR]

The exploration of ultra-wideband electromagnetic shielding materials is still a huge challenge in the elimination of electromagnetic interference from electronic devices of various frequencies in military and civil fields. Herein, a free-standing graphene oxide/silver nanowire (GO/Ag-7L) film with a dense sandwich-like structure is fabricated via vacuum-assisted self-assembly. Compared with the random distribution of physical mixed films, silver nanowires are woven into a 3D conductive network in the multilayer GO/Ag-7L film, which provides a superb electrical conductivity (2255.8 S cm−1). Benefitting from the multilayer structure with multiple absorptions of the GO layer and multiple reflections of the silver nanowire network, the electromagnetic interference shielding effectiveness (EMI SE) is up to 62 dB when the thickness is merely 8 μm in the ultra-wideband of 8–40 GHz (covering the X-band, Ku-band, K-band, and Ka-band). The corresponding specific SE (EMI SE/t) is as high as 77 500 dB cm−1. After inserting the GO layer, the GO/Ag-7L film exhibits outstanding flexibility and anti-corrosion properties. Considering practical application, it can be employed as a novel strain sensor with high sensitivity and a quick strain response in the robotics field, which satisfies the requirement for both electromagnetic interference protection and real-time motion monitoring. Thus, it has promising potential applications in sophisticated electronic equipment. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) nanomaterials with a high surface-to-volume ratio and unique electronic structure have now become one of the hottest topics in photocatalytic research. In parallel with the discovery of emerging photocatalytic materials, strenuous efforts are devoted to maneuvering these surface-related parameters in a predictable manner or to endowing materials with an engineered surface/interface to meet the requirements of photocatalytic reactions. This review endeavors to reveal the inherent functionality of the surface and interface in photocatalysis, with 2D Bi-based photocatalysts as the platform. Herein, we start with various parameters at the surface/interface molecular level, such as defects, surface terminations, facets, pore structures, band bending etc., to gain insight into the structural sensitivity of the surface/interface to the reactivity and selectivity of photocatalytic reactions. As a bridging section, advanced characterization techniques that can visualize the fine structure of the surface/interface at the atomic level are discussed. Special attention is placed on engineering protocols to design and tune 2D Bi-based photocatalysts to ameliorate the performance: surface engineering via heteroatom doping, defect tailoring, and surface state/facet/lateral size and thickness regulation, together with an equal focus on interface engineering including the basal interface and lateral interface. Moreover, the advancements of diversiform photocatalytic applications of 2D Bi-based photocatalysts in ambient molecule activation, including but not limited to CO2 reduction, O2 activation, H2O dissociation, N2 fixation and activation of other molecules, are discussed, with an emphasis on the surface/interface–activity relationship. Finally, the challenges and opportunities in this emerging field are featured based on its current development. The critical thinking on surface/interface chemistry facilitates consolidating and advancing the fundamental theory of heterogeneous photocatalysis and also broadening insights into the rational design of high-performance photocatalysts. [ABSTRACT FROM AUTHOR]

Achieving ultrathin two-dimensional (2D) metal–organic framework (MOF) nanosheets is an extremely meaningful topic and still remains a great challenge. Herein, for the first time, a single-layer 2D Zn-MOF nanosheet was obtained by a facile top-down strategy based on 3D layered Zn-MOF crystals. It involves two steps: firstly, weakening the van de Waals interactions between layers by the protonation of the Zn-MOF under acidic conditions; secondly, further destroying the weakened van der Waals interactions through electrostatic interactions using negatively charged tape molecules, congo red (CR) or methyl orange (MO). Transmission electron microscopy and atomic force microscopy studies demonstrated that ultrathin single-layer (3.4 nm) 2D Zn-MOF nanosheets were obtained, with an ultra-large lateral size (ca. 6 μm), and showed unprecedented adsorption performance toward CR. For CR, the 2D Zn-MOF nanosheets could not only achieve record high uptake capacity (6639.55 mg g−1), but also present efficient and rapid removal. It is worth noting that the adsorption of CR could prevent restacking of the exfoliated 2D Zn-MOF nanosheets and facilitate further exfoliation, which in turn provided more 2D Zn-MOF nanosheets for CR adsorption. Moreover, CR can be selectively and efficiently removed even from the mixed dye solution with different charges. It is anticipated that this methodology could provide a concept to integrate exfoliation and pollutant removal into one process, fulfilling the facile synthesis of ultrathin functionalized 2D nanosheets, with high performance for pollutant removal. [ABSTRACT FROM AUTHOR]

While there has been rapid progress made in the performance of organic photovoltaic (OPV) cells in recent years, the device stability remains a major bottleneck for commercialization. In this work, we blended a stable acceptor (O-IDTBR) with two photostable donors (PTB7-Th and PffBT4T-2OD) having different polymer crystallinity, and the resulting devices show a significant difference in the OPV degradation rate. The OPV devices employing a highly crystalline polymer PffBT4T-2OD as an active layer show a good resistance against light soaking, maintaining 80% of the initial power conversion efficiency (PCE) up to 100 hours, while the devices employing an amorphous polymer PTB7-Th as an active layer show a significant PCE loss in the initial 20 hours mainly due to a rapid loss of the fill factor. By carrying out a comprehensive analysis of the device degradation mechanisms, we conclude that the origin for the PTB7-Th:O-IDTBR device degradation is the formation of mid-gap states under continuous sunlight illumination, leading to a significant drop in electron mobility. Device simulation revealed that deep traps act as charge recombination centers and increase the trap-assisted recombination rate, lowering the FF and Jsc. [ABSTRACT FROM AUTHOR]

Global warming and energy shortage are two major stumbling blocks on the road of human social progress, and have gradually aroused a sense of crisis. Artificial photosynthesis is a two-pronged solution to both problems. However, due to the harsh reaction conditions and low efficiency, traditional semiconductors cannot achieve this. Two-dimensional (2D) materials with larger specific surface areas, lower carrier migration distances, more active surface atoms, and higher elastic strain tolerance play a critical role in the solar to chemical energy conversion scheme, and provide a novel methodology for the synthesis of fine chemicals. This review details the principles of photocatalytic reduction of CO2, and highlights the reduction pathways and product selectivity via experimental methods and theoretical calculations. The state-of-the-art achievements of 2D materials in the field of photocatalytic reduction of CO2 are summarized, mainly including material structure, characteristics, and modification strategies to improve the performance of CO2 reduction. And the research on the combination of 2D materials and single atoms is emphasized. Moreover, bottlenecks and challenges in the design and application of 2D materials, as well as prospects of the future development direction, will be highlighted in order to seek new breakthroughs by exploring new materials design solutions. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) possess large surface area, adjustable pore size and synthetic adaptability which make them promising candidates for diverse applications. However, the low stability and selectivity of pure MOFs are not the optimal configuration for practical applications. Studies have confirmed that the controllable integration of MOFs with graphitic carbon nitride (g-C3N4) not only improves the stability and conductivity of pure MOFs, but also unexpectedly yields new functionalities. These advantages allow the synthesized g-C3N4/MOF-based materials to be applicable to fields other than pure MOFs and have attracted widespread attention in recent years. Herein, the review aims to specifically group together the important reports focused on g-C3N4/MOF-based materials till now. The synthetic methods and applications of composite materials are studied and classified. Furthermore, the review also highlights the functionalities produced by the synergy of two interesting materials, and finally paints a picture of the future. [ABSTRACT FROM AUTHOR]

It is highly desirable and challenging to develop active, inexpensive and available catalysts for the oxygen evolution reaction (OER). Herein, we proposed a simple strategy to anchor MoS2 quantum dots (QDs) on the Mo facet in Mo2C@foam nickel to craft an atomic-level heterostructure (MoS2 QDs@Mo2C@NF). The MoS2 QDs confined in Mo2C established a significant link between the electronic manipulation and activities of Mo2C by combining experiments and first-principles calculations. The Mo facet in Mo2C acting as an electron catcher could accelerate the vertical transmission of electrons from MoS2 QDs to Mo2C and enrich electrons onto the Mo facet. Meanwhile, electrons on Mo2C by electro-excitation could quickly migrate to MoS2 QDs through the intimate Mo (Mo2C)–S bond interfaces, resulting in a highly effective interface with low edge contact resistance. The as-synthesized MoS2 QDs@Mo2C@NF exhibited considerable catalytic activity for the OER in 1 M KOH solution with an overpotential of 1.34 V at 10 mA cm−2 and Tafel slope of 57 mV dec−1 in comparison to RuO2@NF (1.35 V and 41 mV dec−1) owing to optimal adsorption energies of the OER intermediates on the MoS2 QDs@Mo2C@NF, which originated from a strong electronic coupling effect at the heterointerfaces. These results herald the interface modulation of the electrocatalysts in the presence of a support carrier providing a promising strategy for designing advanced electrocatalysts. [ABSTRACT FROM AUTHOR]

Based on a phosphine oxide ligand, HMPA (hexamethylphosphoric triamide), two mononuclear HoIII-pentagonal bipyramidal complexes were synthesized with the formulas [Ho(HMPA)2(H2O)5]2Cl6·2HMPA·2H2O (1) and [Ho(HMPA)2(H2O)5]Br3·2HMPA (2). Single-crystal X-ray diffraction results show that all HoIII ions in both the two complexes are hepta-coordinated and are located in pentagonal bipyramidal {HoO7} coordination polyhedrons constructed by two axial HMPA ligands and five equatorial water molecules. However, due to the employment of different halide ions as counterions, the second coordination sphere surrounding each [Ho(HMPA)2(H2O)5]3+ moiety is different in the two complexes: in 1, three Cl− ions, one water molecule and one HMPA ligand; in 2, three Br− ions and two HMPA ligands. Ac magnetic susceptibilities under zero dc field show that both the two complexes are single-ion magnets with effective energy barriers of 290 K and 320 K for 1 and 2, respectively. Compared with 1, the enhancement in the energy barrier of 2 is believed to be induced mainly by the change in the second coordination sphere rather than the minor differences in the {HoO7} polyhedrons. [ABSTRACT FROM AUTHOR]

A ruthenium-catalyzed allylic C(sp3)–H activation strategy has been employed to develop an intermolecular coupling of alkenyl sulfonamides with alkynes. This protocol features the diastereoselective construction of [3.3.0] and [4.3.0] bicyclic sultams in one step. [ABSTRACT FROM AUTHOR]

The status of photocatalytic (PC)/photoelectrochemical (PEC) water splitting as a promising approach to solar-to-chemical energy conversion has increased significantly over the past several decades for addressing the energy shortage. However, the overall energy conversion efficiency is still relatively poor due to the severe photocorrosion in photosensitive semiconductors. Herein, the review begins with the discussion of the photocorrosion mechanism with several typical semiconductors as examples. Then the feasible characterization methods used to evaluate the stability of semiconductors are summarized. Notably, most studies regarding water splitting focus on achieving high efficiency by improving the charge separation and transfer efficiency within the semiconductors. This review focuses on the recent advances in effective strategies for photocorrosion inhibition of semiconductor-based composites with respect to their intrinsic properties and interface charge transfer kinetics, including morphology/size control, heteroatom doping, heterojunction construction, surface modification, and reaction environment regulation. Furthermore, an in-depth investigation of photocorrosion pathways and mechanisms is critical to accurately and effectively address the photocorrosion of semiconductor-based composites to improve PC/PEC water splitting performance in the future. [ABSTRACT FROM AUTHOR]

A novel 3D coordination polymer {[Cu4.5 (BTZE)1.5 (μ3-OH)3(μ-OH)(SO4)(H2O)1.5·4H2O]}n (1) was synthesized by a solvothermal reaction of 1,2-bis(tetrazol-5-yl) ethane (BTZE) with copper sulfate. Compound (1) contained triangular [Cu3(μ3-OH)] cluster based magnetic Δ-chains linked with in situ generated μ2-BTZE ligands to form a 2D cyclic annular layer. This 2D layer structure was further modified with sulfate and symmetry-related μ3-OH groups, extending to a 3D coordination framework structure. The magnetic performance of (1) was characterized in the temperature range of 2–300 K in terms of direct-current and alternating-current magnetic susceptibilities, revealing that (1) was a canted ferromagnet with a critical temperature (Tc) of 9.5 K. Notably, (1) behaved as a hard magnet with a coercive field of 2.3 kOe at 2 K, showing significant unique characteristics compared to those of the reported spin canting systems based on pure Cu(II) ions. [ABSTRACT FROM AUTHOR]