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Despite the fact that electrocatalysis has made great achievement, it is a challenge to design/fabricate efficient and low-cost electrocatalysts for the generation of hydrogen and oxygen through overall water splitting. Here, flocculent VS nanoparticle aggregate-modified NiCo2S4 nanograss arrays grown on a nickel foam (denoted as VS/NiCo2S4/NF) were fabricated via a hydrothermal method, and were applied as electrodes for overall water splitting. Clearly, the introduction of VS nanoparticle aggregates could modify the electronic structure and offer rich active sites. Moreover, strong electronic interactions between the interfaces of the flocculent VS nanoparticle aggregates and NiCo2S4 nanograss arrays could improve the conductivity and charge transfer capability. Thus, the as-prepared VS/NiCo2S4/NF exhibits outstanding electrocatalytic activity with overpotentials of 332 mV for OER at the current density of 50 mA cm−2 and 187 mV for HER at the current density of 10 mA cm−2 in a 1 M KOH electrolyte, being superior to most of the previously reported Ni/Co-based sulfide electrocatalysts. Besides, the two-electrode system consists of VS/NiCo2S4/NF for overall water splitting under alkaline conditions, and it requires 1.87 V to attain 50 mA cm−2, and maintains this activity for at least 24 h. Our findings could provide an opportunity for the rational design of highly efficient bifunctional composite electrocatalysts towards water splitting.

Controlled synthesis of rare-earth metal-organic frameworks (RE-MOFs) is of great significance to match their emerging multifunctional luminescence applications. Herein, we propose a green and general solvent-free synthetic strategy for the adjustment of morphology and dimension of various RE-MOFs (RE = Eu, Tb, Er, Dy, Y, Tm) by using a tetraethylammonium bromide-assisted thermal-heating method. These self-assembled RE-MOF materials possess controllable morphologies and hierarchical structures while retaining the structural topology of MIL-78, proving that the strategy is a feasible and effective way in opening up large-scale synthesis of RE-MOFs. It is further found that the tetraethylammonium could be carbonized into carbon dots and encapsulated in Eu/Tb-MIL-78 to enhance the fluorescence emission intensities significantly, making the hierarchical Eu/Tb-MIL-78 MOF materials good candidates for the latent fingerprints recognition application. This work provides a novel strategy for effectively controlling the morphology and dimension of RE-MOFs materials with enhanced photoluminescence and has great potential in their scaling-up syntheses and exploring the new luminescence applications.

MXene is a rising star of two-dimensional (2D) materials for energy relative applications, however, the traditional synthesis of MXene etched by hazard HF acid or LiF+HCl mixed solution is highly dangerous with the risk of splashing or pouring liquid solutions. In this work, we developed a water-free ionothermal synthesis of 2D Ti3C2 MXene via etching pristine Ti3AlC2 MAX in low-cost choline chloride and oxalic acid based deep eutectic solvents (DES) with the presence of NH4F, thus it was highly safe and convenient to operate solid precursor and product materials at room temperature. Benefited from the low vapor pressure and solvating properties of DES, the prepared Ti3C2 (denoted as DES-Ti3C2) possessed a high purity up to 98% compared with 95% for HF etched Ti3C2 (denoted as HF-Ti3C2). Notably, an expanded interlayer spacing of 1.35 nm could be achieved due to the intercalation of choline cations in DES-Ti3C2, larger than that of HF-Ti3C2 (0.98 nm). As a result, the DES-Ti3C2 anodes exhibited enhanced lithium storage performance, such as high reversible capacity of 208 mAh g−1 at 0.5 A g−1, and long cycle life over 400 times, outperforming most reported pure MXene anodes. The ionothermal synthesis of MXene developed here may pave a new way to safely prepare other MXene for various energy relating applications.

Multicomponent spinel ferrites are essential to be used in high-performance gas-sensing materials. Herein, multinary (Cu,Zn)Fe2O4 spinel nano-microspheres with tunable internal structures, including solid, core–shell, and yolk–shell, were successfully synthesized by a simple self-templated solvothermal method combined with a subsequent annealing strategy. The internal structures of the (Cu,Zn)Fe2O4 nano-microspheres significantly rely on the heating rates of the precursors, which show promising selective response towards trimethylamine gas. Among them, the as-formed yolk–shell (Cu,Zn)Fe2O4 nano-microspheres exhibited high response to triethylamine with excellent selectivity of STEA/SX = 1.86 at 160 °C, fast response–recovery rate (58 s/136 s), and long-term repeatability and stability of more than one month. The corresponding triethylamine gas-sensing mechanism with the special microstructures is discussed. This work provides new insights into the rational design of interior structure and the modulation of high gas response and selectivity of multinary spinel ferrites in gas-sensing applications.

Growing interest in photochromic materials has largely stimulated researchers in this field to synthesize inorganic–organic materials that are composed of photochromic molecules such as viologen derivatives, naphthalene diimide (NDI) derivatives, and diarylethene derivatives. However, the requirement of an elaborate structural design, complicated synthesis, and high cost remain the issues that need to be addressed before the photochromic materials can be accepted by the market. Their synthesis using low-cost deep-eutectic solvents (DESs) may offer new opportunities to provide cost-effective reaction routes for large-scale synthesis of photochromic materials. We present a multifunctional photochromic inorganic–organic complex |C10H10N2|[GaF(C2O4)2], which is constructed from a nonphotochromic 4,4′-bipyridine ligand and oxalate derived from low-cost DES components. The complex exhibits intriguing photochromic behavior with a wide range of photo-response from UV to visible light and an ultralong-lived charge-separated state. Moreover, it possesses unprecedented tunable photocurrent responses and photocatalytic properties.

The catalytic hydrogenation of CO2 to methane as a promising solution for the utilization of CO2 has aroused intensive attention based on the viewpoints of sustainable use of energy and environment...

A novel three-dimensional open-framework titanophosphite Ti(HPO3)2 (denoted as JIS-15) has been ionothermally synthesized. JIS-15 possesses photovoltaic properties as an n-type semiconductor and exhibits remarkable photocatalytic activity for the degradation of rhodamine B (RhB) under visible light irradiation.

Template-controlled syntheses via metal–organic frameworks (MOFs) have emerged as a general strategy to fabricate metal oxides with tailored porous structures. Here, novel hierarchical SnO2/α-Fe2O3 hollow microcubes have been obtained by post-loading of Sn2+ ions on the surface of Fe4(Fe(CN)6)3 microcubes and a subsequent thermolysis route. The as-formed hierarchical SnO2/α-Fe2O3 composites exhibit remarkable selective acetone-sensing properties, in which the optimum composition of SnO2/α-Fe2O3 with Sn : Fe = 1.5 exhibits the best response towards 200 ppm acetone gas under the operating temperature of 270 °C (with gas response Ra/Rg = 9.3), with a fast response/recovery speed (6 s/7 s), as well as excellent reproducibility for at least 15 days without a significant change in response. The applied strategy provides a general and controllable method to access other hierarchically structured multi-metal oxide architectures with intriguing morphologies and adjustable sensing properties.

Extended exposure to sunlight or artificial UV sources (particularly UVA and UVB) is a major cause of serious skin cancers and ocular diseases. A photochromic inorganic–organic complex was ionothermally synthesized via a decomposition-reassembly strategy, generated from a low-cost deep-eutectic solvent and a 4,4′-bipyridine system. Benefiting from the intrinsic synergy of the hydrogen bonding and π–π stacking interactions, the complex exhibited insensitivity towards visible light, outstanding color contrast from colorless to purple, rapid response time up to seconds, excellent reversibility and high thermal stability. UV index and UVB detection procedures indicated that the coloration performances of the complex exhibited a linear response towards UV index and UVB dose. Besides, the complex can be made to a portable test tablet, a freestanding mixed film with a cellulose paper and a mixed-matrix membrane with PVDF, which make it highly promising for portable and efficient visual UV index and detecting UVB dose.

Hierarchically spinel Ni x Co 1- x Fe 2 O 4 (0.0 ≤ x ≤ 0.5) microcubes were successfully prepared through a combined solvent evaporation strategy and morphology-inherited annealing treatment. By using the Fe-based metal-organic frameworks (MOFs), Fe 4 (Fe(CN) 6 ) 3 , and inorganic Ni 2+ and Co 2+ acetate salts as co-templated precursors, hierarchical Ni-doped spinel CoFe 2 O 4 architecture can be obtained, and the Ni/Co substitution ratios can be controlled systematically. The obtained cubic hierarchical Ni x Co 1- x Fe 2 O 4 , (0.0 ≤ x ≤ 0.5) composites presented highly acetone sensing properties, among which the Ni 0.1 Co 0.9 Fe 2 O 4 composite showed the strongest response performance (with gas response ( R g / R a ) of 1.67 at 240 °C) and excellent reproducibility (for at least 14 cycles), and the proposed acetone sensing mechanism was also discussed. The presented solvent evaporation and co-templated strategy may allow precisely access to fabricating other heteroatom doped inorganic materials with intriguing morphologies, architectures, chemical compositions and tunable sensing properties.

Microwave absorbing materials are usually designed to solve electromagnetic impedance matching by compositing the magnetic and dielectric loss materials. Herein we demonstrated that the Mo@2D-MoS2 nanocomposites synthesized by arc-discharge method exhibit excellent microwave absorbility at gigahertz. Based on the transmission line theory, we prove quantitatively that more than 90% of the electromagnetic power can be attenuated at 5.6–18 GHz. The experimental results and theoretical analyses evidence that the heterogeneous interfaces and the few layers of the two-dimension graphene-like structures of Molybdenum disulfide (MoS2) contribute to the enhancement of the microwave absorption properties. The present study has important implications in understanding the microwave absorbing properties of the 2D materials and provides a new strategy for the design of variety microwave absorbers.

Facile fabrication of new hybrids by post-modification approach is considered to be a straight forward strategy to develop new generation of chemosensor with high sensitivity and selectivity. In this work, a hybrid chemosensor prepared through surface modification of Zn2GeO4:Mn2+ nanorods by zeolitic imidazolate framework-8 (ZIF-8) is reported. Luminescent investigations revealed that the as-prepared Zn2GeO4:Mn2+@ZIF-8 heterostructure featured excellent sensing function with respect to temperature change from 298 K to 423 K, and Cu2+ ions concentration from 1 × 10−4 mol·L−1 to 1 × 10−1 mol·L−1. These results make Zn2GeO4:Mn2+@ZIF-8 composite superb candidate for luminescent applications in thermometers and metal ions detection.

Herein, we present a facile strategy for the preparation of uniform ZnO/ZnFe2O4 hierarchical heterostructures using a Zn–Fe mixed metal–organic framework (Zn(Fe)-MOF) as a precursor via a calcination process. The phase structures, morphologies, and magnetic properties of the as-obtained ZnO/ZnFe2O4 heterostructures were characterized in detail by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM). The ZnO/ZnFe2O4 heterostructures obtained after calcination retained the special microsphere morphology of the Zn(Fe)-MOF, which was assembled from numerous flake-like nanosheets. When served as a photocatalyst for the degradation of rhodamine B (RhB) and methylene blue (MB) dyes in an aqueous solution, the ZnO/ZnFe2O4 heterostructures exhibited a relatively high catalytic performance and excellent resuability upon Xe lamp irradiation. Moreover, they can easily be seperated from the reaction system by an extra magnet; this suggests their potential application in water treatment. This study provides an effective route for the construction of novel multi-component photocatalysts with intriguing microstructures.

ZSM-5 catalysts with different morphologies were synthesized and evaluated for the catalytic conversion of furan in a fixed bed reactor to provide insights into the rational design of zeolite catalysts for catalytic fast pyrolysis (CFP). The effects of mesoporosity and morphology of ZSM-5 catalysts on the production of aromatics and olefins as well as catalyst deactivation were investigated. The results suggest that increasing mesoporosity and decreasing crystallite size can increase furan conversion and affect selectivity to products. Improved selectivities to benzene, toluene, xylene and olefins were achieved with mesoporous ZSM-5 and 100 nm ZSM-5 compared to 800 nm ZSM-5. Coke formation on zeolite catalysts during the reaction of furan was also largely reduced (up to 65%) by introducing mesoporosity. It was observed that coke is mainly formed and accumulated inside the micropores of ZSM-5 catalysts rather than on the external surface or within the mesopores. Characterization of mass transport in the coked zeolite samples using cyclohexane as a probe molecule suggested that coke blocks micropores, leading to a decrease in micropore volume during the catalyst deactivation process. However, due to the three-dimensional pore structure of ZSM-5, the mass transport properties of mesoporous ZSM-5 do not exhibit an apparent change. Catalyst deactivation was mainly due to the coverage of active sites by coke, rather than the blockage of the transport pathways by coke.

The catalytic performance of three-dimensionally ordered mesoporous imprinted (3DOm-i) zeolite catalysts with different frameworks (3DOm-i MFI, 3DOm-i BEA, and 3DOm-i LTA) were investigated by the liquid-phase catalytic conversion of benzyl alcohol in mesitylene and compared to that of other microporous and mesoporous catalysts with a high external surface area, which included MCM-22, 300 nm MFI, ITQ-2, and Al-MCM-41. The mesoporosity in MFI and BEA zeolites can effectively enhance the catalytic performance of the zeolite catalysts for benzyl alcohol self-etherification catalyzed by both the acid sites on the external and internal surface and the alkylation of mesitylene with benzyl alcohol catalyzed exclusively by the acid sites on the external surface. For 3DOm-i LTA, MCM-22, and Al-MCM-41, only the acid sites on the external surface can be utilized in the catalytic reactions. A distinct difference in the product selectivity was also observed for the microporous and mesoporous catalysts.

Sn containing molecular sieves with BEA topology (Sn-BEA) are active Lewis catalysts for a large variety of redox reactions. However, the synthesis of Sn-BEA often requires the use of toxic chemicals (e.g. hydrofluoric acid). In this study, we demonstrated that an active Sn-BEA catalyst can be directly synthesized in a non-fluoride medium via a dry gel conversion method with the aid of seed crystals. It was shown that seeding of zeolite BEA crystals can facilitate crystal growth and lead to BEA topology with framework Sn. Furthermore, it was found that ion-exchange with ammonium ions is indispensable to retain the crystal structure during calcination. The catalytic activity of the Sn-BEA catalyst was evaluated by the isomerization of glucose and reaction of pyruvaldehyde in the aqueous phase, and compared with the conventional hydrophobic Sn-BEA synthesized in a fluoride medium. The catalytic activity of the Sn-BEA synthesized in the absence of fluoride was found to be lower than that of the conventional Sn-BEA for catalyzing the isomerization of glucose in the aqueous phase, which could be attributed to its hydrophilic surface. For the reaction of pyruvaldehyde in the aqueous phase, the Sn-BEA synthesized in this study showed similar activity to the conventional hydrophobic Sn-BEA, indicating that the catalytic activity of Sn-BEA catalysts largely depends on the type of reactions. The current work provides the first example of direct preparation of a Sn-BEA catalyst in a caustic medium.

Process design and techno-economic evaluation of glucose isomerization on Sn-Beta require reliable catalytic reaction rate expressions and kinetic constants. Here, the isomerization of sugars (glucose, fructose and mannose) in water using Sn-Beta is investigated at various temperatures ranging from 70 to 130 °C. It is shown that the catalyst deactivates during the course of the reaction. A phenomenological model that describes the isomerization reaction in the presence of deactivation is developed and the corresponding kinetic constants are estimated from experimental data.

Hierarchical ZnxCd1-xS (x = 1, 0.85, 0.74, 0.64, 0.46 and 0.36) microclusters were successfully prepared by a secondary growth strategy using ethanol as solvent under solvothermal condition. Cluster-like ZIF-8 crystals derived from crystalline hierarchical zinc carbonate, CdCl2 inorganic salt and thiourea were used as the starting materials at stoichiometric ratios. The as-prepared hierarchical hierarchical Zn0.64Cd0.36S material exhibits excellent water splitting performance with a maximum H2 generation rate of 815 μmol g−1 h−1 under visible-light irradiation in the presence of sacrificial agent of 0.25 M Na2S and 0.35 M Na2SO3. This hydrogen generation efficiency is about 23 times higher than that of pure CdS (34.7 μmol g−1 h−1) and 14 times higher than Zn0.64Cd0.36S reference material (56.4 μmol g−1 h−1) prepared by one-pot hydrothermal method. The hierarchical Zn0.64Cd0.36S material exhibits a synergetic effect as a photocatalyst to enhance hydrogen generation and the corresponding photocatalytic mechanism is discussed in detail. This work demonstrates a feasible morphology preservation strategy to prepare novel hierarchical composites with specific chemical composition, high surface area, and abundant active sites, characterized by a rapid diffusion and separation of photogenerated charge carriers proving a visible-light driven photocatalytic hydrogen generation.

Seven new metal–organic frameworks (MOFs) have been synthesized using different organic amines as templates: [Cd(HBTC)2]·2(HDETA)·4(H2O) (1) (BTC = 1,3,5-benzenetricarboxylate and DETA = diethylenetriamine), [Cd2(BTC)2(H2O)2]·2(HCHA)·2(EtOH)·2(H2O) (CHA = cyclohexylamine) (2), [Cd5(BTC)4Cl4]·4(HTEA)·2(H3O) (TEA = triethylamine) (3), [Cd3(BTC)3(H2O)]·(HTEA)·2(H3O) (4), [Zn(BTC)(H2O)]·(HTPA)·(H2O) (TPA = tri-n-propylamine) (5), [Cd(BTC)]·(HTPA)·(H2O) (6), and [Cd2(BTC)(HBTC)]·(HTBA)·(H2O) (TBA = tri-n-butylamine) (7). Topologically, the polymer 1 exhibits a two-dimensional (2D) Cd-HBTC network with (44) topology, which is a sql structure; the polymer 2 possesses a three-dimensional (3D) porous Cd-BTC framework with (4·62)2(42·610·83) topology, which is a contorted rutile structure; polymer 3 exhibits a 3D open Cd-BTC architecture with (62·82·102)2(62·84)(63)4 topology; polymer 4 is a 3D porous Cd-BTC network with new (4·62)2(42·64·86·103)(6·82)2(62·84)(62·84)2(62·8)2 topology; similar to 1, polymer 5 is a 2...

Pores for thought: Chemical liquid deposition of silica onto ZSM-5 catalysts led to smaller pore openings that resulted in >90% selectivity for p-xylene over the other xylenes in the catalytic fast pyrolysis of furan and 2-methylfuran (see scheme). The p-xylene selectivity increased from 51% with gallium spray-dried ZSM-5 to 72% with a pore-mouth-modified catalyst in the pyrolysis of pine wood.