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Tin-based materials are promising anode candidates profiting from their high theoretical capacities compared with that of commercial graphite to enhance energy efficiency and power capabilities for secondary batteries. Herein, Dictyophora-shaped hierarchically porous Mn2SnO4/C composite materials were facilely prepared by a sol–gel process accompanied by phase separation, followed by a controllable two-step heat treatment. The heat treatment temperature and atmosphere have an important effect on the phase composition, pore structure and electrochemical performances of tin-based materials. The crystalline Mn2SnO4/C composite can be obtained via a two-step heat-treatment (first in air and then in argon), whereas a mixture of Mn3O4 and SnO2 will be achieved through a one-step heat-treatment in air. The synthesized hierarchically porous Mn2SnO4/C composite has 3D bicontinuous skeletons and a hierarchical micro–meso–macropore structure with wide pore size distribution, and has high reversible capacity (939.9 mA h g−1 at 200 mA g−1), and great rate retention (36.5% capacity retention from 0.1 to 10 A g−1), as well as good cycle stability, delivering a high specific capacity of 784.1 mA h g−1 at 1 A g−1 after 500 cycles. The enhanced performances can be attributed to the hierarchical pore structure, which not only assists electron and Li-ion transportation but also creates more active sites. The hierarchically porous electrode design strategy has potential in high-capacity and fast-rate energy storage devices. [ABSTRACT FROM AUTHOR]

Macroporous europium-doped Ca12Al14O33 (C12A7:Eu3+) was prepared via a sol–gel method followed by heat-treatment, and the crystal structure, luminescence performance and metal ion luminescence sensing of C12A7:Eu3+ were investigated and evaluated in detail. The process of the sol–gel method and heat-treatment promotes the formation of a single mayenite phase C12A7:Eu3+, and the Eu3+ ions are incorporated into the crystal lattice and replace the position of the Ca2+ ions without destroying the lattice structure of C12A7. The interconnected macropores not only increase the lighting area but also reduce the concentration quenching effect, leading to a significant enhance of luminescence intensity. The resultant macroporous C12A7:Eu3+ can be used as a luminescence performance sensor and displays the potential practical application for metal ion detection. The macroporous C12A7:Eu3+ sensor has a good response to Pb2+ ions, whose linear equation between concentration (CPb) and luminescence intensity (F) of (F0−F)/F0 = 1.412 + 0.3428 log10(CPb) can be obtained. [ABSTRACT FROM AUTHOR]

Fe3O4@polydopamine@polyamidoamine (Fe3O4@PDA@PAMAM) core–shell nanocomposites were successfully fabricated through a monodispersed Fe3O4 nanoflower synthesis, PDA modification and PAMAM grafting. The as-prepared single Fe3O4@PDA@PAMAM nanocomposite possesses a high relevant saturation magnetization (Ms) (30.25 emu g−1), while the coercivity (Hc) (10.85 Oe) and retentivity (Mr) (0.9062 emu g−1) were extremely low. The obtained Fe3O4@PDA@PAMAM has an adsorption capacity as high as 97.18 mg g−1 for Cu(ii), and the adsorption process is in conformity with pseudo-second-order kinetics and the Langmuir isotherm model. Moreover, the effect of pH and thermodynamics of the adsorption process is also discussed briefly. [ABSTRACT FROM AUTHOR]

Herein, macroporous CuAl2O4 spinel monoliths derived from ionic precursors were successfully synthesized via a sol–gel route in the presence of propylene oxide (PO) and poly(ethylene oxide) (PEO). PO and PEO cooperatively control the sol–gel transition and phase separation of the system to form gels with a phase-separated macrostructure. The resultant xerogel exists in the form of a monolith and possesses interconnected macroporous channels and co-continuous dense skeletons composed of amorphous Al(OH)3 and Cu2(OH)3Cl. Heat-treatment allows the formation of the single crystalline phase CuAl2O4 spinel without the destruction of well-defined interconnected channels, and the CuAl2O4 spinel monoliths with a macropore size of 0.5–1 μm and porosity of 55–70% can be obtained after heat-treatment. In this study, three anionic dyes and two cationic dyes were selected as adsorbates to investigate the selective adsorption ability of the resultant monoliths. Results indicate that the as-prepared CuAl2O4 spinel heat-treated at 600 °C shows a high affinity and adsorption rate towards the anionic dyes congo red (∼100%) and methyl blue (∼81.8%) within 10 min except towards methyl orange (∼25.5%); thus, the abovementioned spinel can be used for the efficient and selective adsorption of certain anionic dyes from a binary cationic–anionic dye system or fast separation of methyl orange (MO) from a double anionic dye system. [ABSTRACT FROM AUTHOR]

Hierarchically porous AlPO4 monoliths with well-defined macropores are prepared via a sol–gel process accompanied by phase separation. Appropriate amounts of the precursors, poly(ethylene oxide) and propylene oxide, allow the formation of a mesoporous structure with uniform macropore size distribution in the gel. A crystalline phase of tridymite forms after heat-treatment at 1000 °C in air, while the meso- and macro-porous structure is preserved, maintaining a BET surface area of 120.8 m2 g−1. The resultant crystalline AlPO4 monolith is used as the host to immobilize silver nanoparticles (Ag NPs) by immersing it in silver colloid under an ambient condition. The result shows that Ag NPs were homogeneously embedded on the surface of skeletons without spoiling the appearance and macroporous structure of the initial AlPO4 monolith. Ag NPs embedded in monolithic AlPO4 show promise in a wide range of applications, including catalysis and separation. [ABSTRACT FROM AUTHOR]

Monolithic mayenite with well-defined macropores has been successfully synthesized from ionic precursors via a sol–gel process accompanied by phase separation. The addition of propylene oxide (PO) to the starting solution leads to homogenous gelation and modifies the gel skeleton, whereas the addition of poly(ethylene oxide) (PEO) induces phase separation. Glycol acts as a chelating agent to suppress the precipitation of Ca2+ ions, and formamide works as a drying control chemical additive to enhance the drying behavior. Appropriate amounts of solvents, PEO, and PO allow the formation of calcium aluminate gels with co-continuous macroporous structure. The reaction mechanism of the sol–gel process of the Ca–Al–O system is also investigated by TG-DSC, FT-IR and NMR. The dried gels are amorphous and the crystalline phase Ca12Al14O32Cl2 forms after heat-treatment at 1000 °C in air, while the macroporous structure is preserved. The resultant monoliths before and after heat-treatment possess both high porosity and smooth and dense skeletons. [ABSTRACT FROM AUTHOR]