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The development of bifunctional electrochemically-active micro-/nanomaterials with heterostructures for both supercapacitors and hydrogen evolution reaction (HER) enables the possibility to integrate energy storage and conversion into one single system. Herein, heterostructural NiCo2S4@MoS2 materials have been successfully prepared using zeolitic imidazolate frameworks as templates, including transformation to bimetallic layered double hydroxide, and sequential sulfuration. The smart process entails an assembly of MoS2 nanosheets on NiCo2S4 nanobuilding blocks with hollow core–shell nanoarchitectures. Specifically, when tested as an electrode in a supercapacitor, it can deliver an increased specific capacitance of 860 F g−1 at a current density of 1 A g−1, superior rate capability and cyclic stability. Furthermore, the NiCo2S4@MoS2 heterostructure also efficiently electrocatalyzes the HER in an alkaline electrolyte with a low overpotential of 194 mV, a favorable HER kinetics and better long-term stability. Results of both scenarios attest to the enhanced electrochemical performance of the NiCo2S4@MoS2 heterostructure compared to its NiCo2S4 counterpart, which is attributed to the hollow porous core–shell structures, nanointerface engineering and the synergistic effect between NiCo2S4 and MoS2. This work will broaden our horizons in designing and fabricating multifunctional active materials for next generation energy storage and conversion applications. [ABSTRACT FROM AUTHOR]

The online detection of n‐propanol concentration is required for health and safety issues in industry. Herein, through a morphology‐inherited annealing treatment of Ni/Fe bimetallic metal‐organic framework as the template, this paper reported the synthesis of porous javelin‐like NiFe2O4 nanorods. As gas sensing material, the ferrite showed n‐type gas‐sensing behavior as its resistance decreased in reducing gas atmospheres, and exhibited excellent n‐propanol sensing performance (the sensing response is 6.4 to 5 ppm) with ultralow detection limits (0.41 ppm) and ultrahigh gas sensitivity (1.13 ppm−1) toward n‐propanol at relatively low working temperature (120 °C). Meanwhile, the sensor showed good selectivity to n‐propanol as well as excellent cyclic and long‐term stability. The unique morphology and porous structure of NiFe2O4 nanorods may be responsible for the excellent performance, which offer more reactive sites and accelerate the diffusion of n‐propanol gas. This facile method of preparing porous metal oxides could be extended to fabricate other gas sensing materials applied to detect other target gases. As a gas sensor, javelin‐like porous NiFe2O4 prepared by annealing Ni/Fe bimetallic MOFs exhibits excellent response to n‐propanol with low limit of detection (0.41 ppm). [ABSTRACT FROM AUTHOR]

Through annealing treatment of Ni/Fe-fumaric acid bimetallic MOF precursors, hollow NiFe2O4 hexagonal biyramids were synthesized. When evaluated as sensing materials, the n-type semiconductive sensor exhibited high performances including a high response value of 32.19 after exposure to 200 ppm n-propanol and good selectivity and cyclic stability when operating at a low temperature (120 °C). [ABSTRACT FROM AUTHOR]

Abstract: Two novel lanthanide metal‐organic frameworks (LnMOFs), {[Me2NH2]2[Eu4(L)5(SO4)2]⋅H2O}n (EuMOF‐1) and {[Me2NH2][Tb(L)(SO4)(H2O)]}n (TbMOF‐2), were successfully synthesized by using protonated pyridine‐3,5‐dicarboxylic acid sulfate ligand (H3L+⋅1/2SO42−) under identical solvthermal conditions. To our delight, structural analyses indicate that these two LnMOFs (Ln=Eu or Tb) exhibit two extremely different structures in terms of three‐dimensional open framework and two‐dimensional stacking layered network, which is entirely different from the usual isostructures of LnMOFs (Ln=Eu and Tb). The “Gadolinium break” effect was unprecedentedly observed, leading to phase transformation from EuMOF‐1 to TbMOF‐2 by gradual decrease of Eu content. A serious of bimetallic EuxTb1−x MOFs (x=0.8, 0.6, 0.4, 0.2) materials during phase transformation process were achieved. When evaluated as luminescent quenching sensors for Fe3+ ion, the KSV constant was increased by 36.6% from monometallic EuMOF‐1 to bimetallic Eu0.6Tb0.4 MOF. Additionally, the exclusive sensing and its enhancing mechanism towards Fe3+ are further discussed. This work would establish a new strategy for enhancing the sensing performance of luminescent lanthanide MOFs. [ABSTRACT FROM AUTHOR]

Mercury(II) ions have emerged as a widespread environmental hazard in recent decades. Despite different kinds of detection methods reported to sense Hg2+, it still remains a challenging task to develop new sensing molecules to replenish the fluorescence-based apparatus for Hg2+ detection. This communication demonstrates a novel fluorescent sensor using UiO-66-NH2 and a T-rich FAM-labeled ssDNA as a hybrid system to detect Hg2+ sensitively and selectively. To the best of our knowledge, it has rarely been reported that a MOF is utilized as the biosensing platform for Hg2+ assay. [ABSTRACT FROM AUTHOR]

A new anionic framework {[Me2NH2]0.125[In0.125(H2L)0.25] ⋅ xDMF} n ( 1) with one-dimensional (1D) channels along the c axis of about 13.06×13.06 Å2, was solvothermally synthesized and well characterized. Post-synthetic cation exchange of 1 with Eu3+, Tb3+, Dy3+, Sm3+ afforded lanthanide(III)-loaded materials, Ln3+@ 1, with different luminescent behavior, indicating that compound 1 could be used as a potential luminescent probe toward different lanthanide(III) ions. Additionally, compound 1 exhibits selective adsorption ability toward cationic dyes. Moreover, the RhB@ 1 realized the probing of different organic solvent molecules by tuning the energy transfer efficiency between two different emissions, especially for sensing DMF. This work highlights the practical application of luminescent guest@MOFs as sensors, and it paves the way toward other one/multi-color luminescent host-guest systems by rational selection of MOF hosts and guest chromophores with suitable emissive colors and energy levels. [ABSTRACT FROM AUTHOR]

Stimuli‐responsive structural transformations are emerging as a scaffold to develop a charming class of smart materials. A EuL metal‐organic framework (MOF) undergoes a reversible temperature‐stimulated single‐crystal to single‐crystal transformation, showing a specific behavior of fast capture/release of free Eu3+ in the channels at low and room temperatures. At room temperature, compound 1a is obtained with one free carboxylate group severing as further hook, featuring one‐dimensional square channels filled with intrinsic free europium ions. Trigged by lowering the ambient temperature, 1b is gained. In 1b, the intrinsic free europium ions can be fast captured by the carboxylate‐hooks anchored in the framework, resulting in the structural change and its channel distortion. To the best of our knowledge, this is the first report of such a rapid and reversible switch stemming from dynamic control between noncovalent and covalent Eu–ligand interactions. Utilizing EuL MOF to detect highly explosive 2,4,6‐trinitrophenol at room temperature and low temperature provides a glimpse into the potential of this material in fluorescence sensors. [ABSTRACT FROM AUTHOR]

In this work, we present a strategy to improve the gas-sensing performance of NiFe2O4 via a controllable annealing Ni/Fe precursor to fluffy NiFe2O4 nanosheet flowers. X-ray diffraction (XRD), a scanning electron microscope (SEM), nitrogen adsorption–desorption measurements and X-ray photoelectron spectroscopy (XPS) were used to characterize the crystal structure, morphology, specific surface area and surface structure. The gas-sensing performance was tested and the results demonstrate that the response was strongly influenced by the specific surface area and surface structure. The resultant NiFe2O4 nanosheet flowers with a heating rate of 8 °C min−1, which have a fluffier morphology and more oxygen vacancies in the surface, exhibited enhanced response and shortened response time toward ethanol. The easy approach facilitates the mass production of gas sensors based on bimetallic ferrites with high sensing performance via controlling the morphology and surface structure. [ABSTRACT FROM AUTHOR]

Rational design of electrode materials can often improve the energy density/power density and service life of supercapacitors. In this study, we have developed and synthesized CuWO 4 @NiCoWO 4 porous nanorod array supported on copper foam using a solution immersion method at room temperature, in combination with thermal dehydration and hydrothermal strategies. The distinctive porous and heterogeneous structure, along with the synergistic effects among multiple components, maximize the electrochemical properties of the active components, leading to excellent electrochemical properties of the electrode material. Consequently, high capacitance (4.048 F cm−2 at 5 mA cm−2), excellent rate performance (88.3% retention at 30 mA cm −2), and long-lasting cycling stability (83.5% retention after 20,000 cycles) can be acheived by the CuWO 4 @NiCoWO 4 binder-free electrode loaded on copper foam. In addition, CuWO 4 @NiCoWO 4 //AC button-type asymmetric supercapacitors were assembled and demonstrated good energy storage performance. It can achieve an energy density of 0.35 mW h cm−2 (20.19 Wh kg−1) and maintain an impressive capacitance retention of 96.79% after 10,000 cycles. Notably, this work introduces a new approach for preparing polymetallic tungstate composites for potential use in electrochemical energy storage devices. • Self-supported CuWO 4 @NiCoWO 4 porous core-shell nanorod arrays are obtained on Cu foam. • The electrode achieves high areal capacitance, enhanced rate performance and long durability. • ASC device delivers an excellent energy storage performance and cycling stability. • Heterojunction interface regulation effectively improves electrochemical performance. • A rational design of electrode material is a key to improve the energy storage performance. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) have been used as sacrificial templates to fabricate porous metallic oxides. However, its usage is limited in preparing rare earth perovskite-type oxides, which are usually synthesized by sol-gel method. Herein, sol-gel route was employed to construct the uniform La/Fe MOFs, completed in several seconds at room temperature. The fabricated LaFeO 3 /La 2 O 3 , LaFeO 3 and LaFeO 3 /Fe 2 O 3 have porous structure, and the LaFeO 3 possesses the largest specific surface area of 18.16 m2/g. Besides, abundant oxygen species exist on the surface of LaFeO 3 /La 2 O 3 and LaFeO 3 , with percentages of 68.13 % and 64.15 % in O 1 s spectra, respectively. Benefit from the morphology structure and elements states, the LaFeO 3 -based sensor exhibits an ultra-high response of 258.4–100 ppm n-propanol, and the LaFeO 3 /La 2 O 3 -based sensor possesses the detection limit of 0.16 ppm, at a quite low working temperature of 100 ℃. This work provided a facile, universal, and adjustable approach to design perovskite metal oxides for ultra-sensitive detection of various gases. • This synthesis of materials with porous is facile, universal, and timesaving. • The obtained LaFeO 3 /La 2 O 3 and LaFeO 3 possess large content of surface oxygen species. • The sensor based on LaFeO 3 displays a response of 258.4–100 ppm n-propanol. • The sensor exhibits low power consumption, with an operating temperature of 100 °C. [ABSTRACT FROM AUTHOR]

Real-time detection of acetone vapor at low concentration plays a decisive role in early noninvasive diagnosis of diabetes. In this work, porous NiFe 2 O 4 crystalline nanocubes have been scalably prepared via an as-developed cost-efficient and facile strategy, which involves a morphology-inherited annealing treatment of single-resource Prussian Blue analogue of Ni 3 [Fe(CN) 6 ] 2 · x H 2 O solid nanocubes as self-sacrificial templates. The porous NiFe 2 O 4 crystalline nanocubes are demonstrated to be composed of primary nano building blocks and interconnected pores. When utilized as sensing materials, the as-synthesized NiFe 2 O 4 exhibited p-type gas-sensing behavior that the resistance increases in a reducing gas atmosphere. Furthermore, the as-fabricated NiFe 2 O 4 sensor was sensitive and selective to acetone gas with an obvious response value of 1.9 at its low concentration (1 ppm) and low detection of limit (0.52 ppm) at a quite low working temperature (160 °C). In addition, the sensing mechanism is deeply investigated. More significantly, our prominent findings herein shed light on the fabrication of metal oxide based gas sensors in environmental and medicinal fields. [ABSTRACT FROM AUTHOR]

ZnCo bimetallic LDH is successfully grown on 3D Co 3 O 4 scaffolds on nickel foam as a stable hierarchical core–shell heterostructural electrode. Benefiting from the fine ion/electron transport within Co 3 O 4 @Zn 1 Co 2 -LDH electrode, the prepared Co 3 O 4 @Zn 1 Co 2 -LDH//ZiF-8 DC asymmetric supercapacitor exhibits a high energy density of 1.1 mWh cm−2 at a power density of 4.0 mW cm−2, which is superior to the values of previous reports. [Display omitted] • Three-dimensional binder-free electrodes are constructed with a core–shell heterostructure. • The electrode material can achieve a high quality loading of 13–15 mg cm−2. • The electrode achieves high areal capacitance of 10.5 F cm−2 at 5 mA cm−2 and high long durability. • The ASC device delivers a high energy density of 1.1 mWh cm−2 at a power density of 4.0 mW cm−2. • The ASC device shows 82.0 % of capacitance retention after 10,000 cycles at 30 mA cm−2. Rational design of electrode material structure is a key factor to improve high energy density/power density and long lifetime of supercapacitors. Here, a simple two-step hydrothermal strategy was used to synthesize Co 3 O 4 on nickel foam (NF), and a core–shell heterostructure was constructed by growing ZnCo bimetallic layered double hydroxides (LDH) on Co 3 O 4 scaffolds. Because of its unique heterogeneous structure and optimization of different components, the electrochemical performance of the active components was maximized because of the synergistic effect. The electrode material can achieve a high- quality loading of 13–15 mg cm−2. The binder-free electrode material Co 3 O 4 @Zn 1 Co 2 -OH grown directly on NF can achieve a high areal capacitance of 10.5 F cm−2 at 5 mA cm−2 and rate performance (82.9 % retention at 30 mA cm−2) and long durability (62.3 % capacitance retention at 30 mA cm−2). Additionally, a Co 3 O 4 @Zn 1 Co 2 -LDH//ZiF-8 DC (ZiF-8 Derived Carbon) asymmetric supercapacitor (ASC) is assembled with an operating voltage of 1.5 V. The ASC device delivers a maximum energy density of 1.1 mWh cm−2 (33.7 Wh kg−1) at a power density of 4.0 mW cm−2 (19.6 W kg−1) and exceptional cycling stability (82.0 % of capacitance retention after 10,000 cycles at 30 mA cm−2). This work demonstrates that hierarchical core–shell heterostructures show great potential in development of next-generation electrochemical energy storage devices. [ABSTRACT FROM AUTHOR]

Molecular hydrogen has been considered as ideal energy carrier due to its high calorific value and clean product, which also requires eco-friendly generation process. Electrocatalytic H 2 evolution from water splitting represents a compelling sustainable and green energy technology, but it is severely hindered by the large overpotential needed, especially for non-noble metal electrocatalysts. In this study, an interface engineering strategy is extended to improve the catalytic hydrogen evolution reaction (HER) performance of CoP by introducing CeO 2 component. The novel heterostructure of CoP/CeO 2 is successfully fabricated by a selective phosphidation treatment of pre-synthesized Co-PBA/CeO 2 hybrid precursor. The introduced CoP/CeO 2 hetero-interface would regulate the electronic structure, accelerate charge transfer and enhance the intrinsic activity of the active sites. By optimizing the content of functional CeO 2 entity, the CoP/CeO 2 -2.5 is the most active electrocatalyst with the lowest overpotential of 152 mV to reach 10 mA cm−2 current in 1.0 M KOH, as well as a Tafel slope of 83.5 mV dec−1. Besides, CoP/CeO 2 -2.5 can also continuously operate well for more than 16 h, demonstrating the good durability of this electrocatalyst. This work would broaden the advanced HER electrocatalysts by fabricating hetero-interface with different functional components. [Display omitted] • Heterostructural CoP/CeO 2 electrocatalysts were fabricated via phosphidation treatment of Co-PBA/CeO 2 templates. • The CeO 2 engaged interface can accelerate charge transfer, expose more active sites and enhance the intrinsic activity. • The CoP/CeO 2 -2.5 electrocatalyst exhibits only 152 mV overpotential to drive 10 mA cm−2 current towards HER. [ABSTRACT FROM AUTHOR]

Ultra-thin two-dimensional nanosheets have attracted increasing attention due to their great application prospects in nanomaterial science and biomedicine. Herein, we report the preparation of exfoliated raw and oxidized 4-layer Ti 7 O 13 (O-Ti 7 O 13) and their ability to produce reactive oxygen species (ROS). The results show that O-Ti 7 O 13 nanosheets can effectively produce ROS induced by X-ray irradiation. The 4-layer nanosheets can quickly load doxorubicin (DOX) within 5 min with a high loading rate to obtain a novel nanodrug system through their electrostatic adsorption capacity, and they exhibit a sustained release behavior. In this way, chemotherapy, radiation therapy and photodynamic therapy effectively combine for cancer synergistic treatment. We evaluated the cytotoxicity, cellular uptake and intracellular location of the O-Ti 7 O 13 nanosheet-based drug delivery system in A549 lung cancer cells. Our results show that the O-Ti 7 O 13 /DOX complex is more cytotoxic to A549 cells than free DOX since a low concentration of loaded DOX (10 μg/mL) with a low dose of X-rays can cause the complete apoptosis of tumor cells. This work reveals that the therapeutic effect of DOX-loaded O-Ti 7 O 13 nanosheets is strongly dependent on their loading mode, and the effects of chemotherapy and photodynamic therapy are enhanced under X-ray irradiation, which allows O-Ti 7 O 13 nanosheet use as a photo-activated drug carrier. This work provides a new strategy for preparing 2D metal oxide nanosheets toward biomedical applications. • High dispersed 4-layers O-Ti 7 O 13 nanosheets are synthesized. • O-Ti 7 O 13 nanosheets effectively produce ROS induced by X-ray irradiation. • O-Ti 7 O 13 nanosheets show pH-responsive behavior in DOX drug loading and release. • Killing rate of A549 cells is near 100% by O-Ti 7 O 13 -DOX under X-ray irradiation. • Tumor synergistic therapy is achieved by O-Ti 7 O 13 based drug delivery system. [ABSTRACT FROM AUTHOR]

Synthesis of SiO 2 coated magnetic Fe 3 O 4 nanoparticles as a DOX carrier and photosensitizer to enhance the synergistic effect of chemo-photothermal therapy for tumor treatment. • Size controllable magnetic Fe 3 O 4 @SiO 2 core-shell nanocomposites were synthesized by a modified Stǒber method. • Magnetic Fe 3 O 4 @SiO 2 have pH-responsive behavior in drug loading and release. • Fe 3 O 4 @SiO 2 can raise temperature to 55 °C for only 10 min irradiation by 808 nm light. • 81.3% of A549 cells are killed after incubated with Fe 3 O 4 @SiO 2 @DOX containing only 0.5 μg/mL of DOX and 15 min NIR irradiation • Tumor synergistic treatment is achieved by combination of chemotherapy and photothermal therapy. In this study, we integrated chemotherapy and photothermal therapy in a magnetically targeted doxorubicin-loaded Fe 3 O 4 @SiO 2 nanodrug system. Size-controllable magnetic Fe 3 O 4 @SiO 2 core-shell nanoparticles were synthesized via a solvothermal method and a modified Stǒber method. A molecular anticancer drug, namely, doxorubicin, was loaded onto Fe 3 O 4 @SiO 2 nanocomposites to form a magnetically targeted drug delivery system. This drug delivery system exhibits pH-sensitive effects on drug loading and release. The drug loading rate in a neutral environment is higher than that in an acidic environment; the opposite property is observed for the release rate. In addition, the magnetic Fe 3 O 4 @SiO 2 nanocomposites exhibit a satisfactory photothermal effect under NIR (808 nm) irradiation. The temperature can increase to 55 °C after only 10 min of irradiation, which effectively induces apoptosis of cancer cells in vitro. The cytotoxicity and cellular uptake of Fe 3 O 4 @SiO 2 @DOX nanodrugs were evaluated in A549 lung cancer cells. After treatment with Fe 3 O 4 @SiO 2 @DOX that contains only 10 μg/mL of DOX, 82.8% of A549 lung cancer cells can be killed. Furthermore, 81.3% of A549 lung cancer cells are killed after incubation with Fe 3 O 4 @SiO 2 @DOX that contains only 0.5 μg/mL of DOX and 15 min of NIR irradiation, thereby suggesting an excellent synergistic chemo-photothermal effect in tumour therapy. Our results suggest a new approach for the synthesis of a multifunctional, highly targeted, size-controlled nanodrug for tumour synergistic therapy. [ABSTRACT FROM AUTHOR]

High-/medium-entropy materials have been explored as promising electrocatalysts for water splitting due to their unique physical and chemical properties. Unfortunately, state-of-the-art materials face the dilemma of explaining the enhancement mechanism, which is now limited to theoretical models or an unclear cocktail effect. Herein, a medium-entropy NiCoFeMnP with an advanced hierarchical particle-nanosheet-tumbleweed nanostructure has been synthesized via simple precursor preparation and subsequent phosphorization. Evaluated as the electrocatalyst for oxygen evolution reaction (OER), the medium-entropy NiCoFeMnP displays a lower overpotential of 272 mV at a current density of 10 mA cm -2 , and more favorable kinetics than the binary NiFeP, ternary NiCoFeP, quaternary NiCoFeCuP and NiCoFeCrP counterparts, and other reported high-/medium-entropy electrocatalysts. Careful experimental analyses reveal that the incorporation of Mn can significantly regulate the electronic structure of Ni, Co, and Fe sites. More importantly, the Mn introduction and entropy stabilization effect in the reconstructed metal (oxy)hydroxide simultaneously promote the lattice oxygen mechanism, improving the activity. This work sheds new light on the design of high-/medium-entropy materials from an in-depth understanding of the underlying mechanism for improving energy conversion efficiency.

The pursuit of highly efficient electrocatalysts for the alkaline hydrogen evolution reaction (HER) is of paramount importance for water splitting. However, it is still a formidable task in Mo 2 C-based materials because of the agglomeration and strong Mo-H binding of Mo 2 C units. Herein, a novel CeOCl-CeO 2 /Mo 2 C heterostructure nesting within a three-dimensional porous nitrogen-doped carbon matrix has been designed and used for catalyzing HER via simultaneous morphology and heterointerface engineering. As expected, the optimal CeOCl-CeO 2 (0.2)/Mo 2 C@3DNC exhibits impressive HER activity, with a low overpotential of 156 mV at a current density of 10 mA cm -2 coupled with a slight Tafel slope of 62.20 mV dec -1 . Introducing a Ce promoter, that is CeOCl and CeO 2 , would endow the interface with an internal electric field and electron redistribution between CeOCl-CeO 2 and Mo 2 C induced by the heterogeneous work function difference. Moreover, experimental investigation and density functional calculations confirm that the CeOCl-CeO 2 /Mo 2 C heterointerface can downshift the d-band center of the active Mo center, weakening the strength of the Mo-H coupling. This proposed concept, engineering Ce-based promoters into active entities involved in the heterostructure to modulate intermediate adsorption, offers a great opportunity for the design of superior electrocatalysts for energy conversion.