Showing papers on "Mesoporous material published in 2018"
TL;DR: In this paper, hexagonally-ordered mesoporous carbon (CMK-3) was applied to activate persulfate (PS) for the degradation of 2,4-dichlorophenol (2, 4-DCP) with superior removal rate of 90% in 20min.
Abstract: Metal-free catalysis for green degradation of aqueous organic pollutants has caused extensive concern in recent years. In this study, hexagonally-ordered mesoporous carbon (CMK-3) was applied to activate persulfate (PS) for the degradation of 2,4-dichlorophenol (2,4-DCP) with superior removal rate of 90% in 20 min. The high catalytic efficiency was probably ascribed to the accelerated electron transfer resulting from the large adsorption capacity of CMK-3. It was found that specific surface areas (SSA), defective sites and functional groups on the activator were highly related to its catalytic efficiency and passivation. Compared to other nanocarbons, CMK-3 had better reusability due to its ordered mesoporous structure with large SSA and high defective degrees. For the first time, a two-pathway mechanism was proposed for metal-free activation process of PS, indicating that radical and non-radical oxidation worked together in PS activation for complete 2,4-DCP decomposition, and non-radical pathway played a dominant role while radical pathway was critical in accelerating the reaction. OH, SO4 − and O2 − all took part in the radical oxidation process, in which the contribution of OH was dominant. Besides, high decomposition efficiency was also achieved in pharmaceutical wastewater treatment by the CMK-3/PS system. This research proposed a new electron transfer mechanism for metal-free activation process of PS, which can provide a theoretical support for further studies.
539 citations
TL;DR: The exciting progress in the development of MSNs-based effective delivery systems for poorly soluble drugs, anticancer agents, and therapeutic genes are highlighted.
433 citations
TL;DR: In this paper, a single-atomic Cu substitution in CeO2(110) surface can stably enrich up to three oxygen vacancies around each Cu site, yielding a highly effective catalytic center for CO2 adsorption and activation.
Abstract: The electrocatalytic reduction of CO2 into value-added chemicals such as hydrocarbons has the potential for supplying fuel energy and reducing environmental hazards, while the accurate tuning of electrocatalysts at the ultimate single-atomic level remains extremely challenging. In this work, we demonstrate an atomic design of multiple oxygen vacancy-bound, single-atomic Cu-substituted CeO2 to optimize the CO2 electrocatalytic reduction to CH4. We carried out theoretical calculations to predict that the single-atomic Cu substitution in CeO2(110) surface can stably enrich up to three oxygen vacancies around each Cu site, yielding a highly effective catalytic center for CO2 adsorption and activation. This theoretical prediction is consistent with our controlled synthesis of the Cu-doped, mesoporous CeO2 nanorods. Structural characterizations indicate that the low concentration (<5%) Cu species in CeO2 nanorods are highly dispersed at single-atomic level with an unconventionally low coordination number ∼5, su...
429 citations
TL;DR: In this article, a solar steam generation device is designed utilizing crossplane water transport in wood via nanoscale channels and the preferred thermal transport direction is decoupled to reduce the conductive heat loss.
Abstract: Solar steam generation is regarded as one of the most sustainable techniques for desalination and wastewater treatment. However, there has been a lack of scalable material systems with high efficiency under 1 Sun. A solar steam generation device is designed utilizing crossplane water transport in wood via nanoscale channels and the preferred thermal transport direction is decoupled to reduce the conductive heat loss. A high steam generation efficiency of 80% under 1 Sun and 89% under 10 Suns is achieved. Surprisingly, the crossplanes perpendicular to the mesoporous wood can provide rapid water transport via the pits and spirals. The cellulose nanofibers are circularly oriented around the pits and highly aligned along spirals to draw water across lumens. Meanwhile, the anisotropic thermal conduction of mesoporous wood is utilized, which can provide better insulation than widely used superthermal insulator Styrofoam (≈0.03 W m−1 K−1). The crossplane direction of wood exhibits a thermal conductivity of 0.11 W m−1 K−1. The anisotropic thermal conduction redirects the absorbed heat along the in-plane direction while impeding the conductive heat loss to the water. The solar steam generation device is promising for cost-effective and large-scale application under ambient solar irradiance.
388 citations
TL;DR: In this article, a facile one-pot soft-templating and one-step pyrolysis method was used to synthesize carbon spheres with mesoporous structure and nitrogen doping for high-performance supercapacitor applications.
326 citations
TL;DR: The battery based on these Co3 O4 /N-rGO nanosheets demonstrates enhanced and stable electrochemical performance, even under severe deformation, and can be successfully knitted into clothes without short circuits under external forces.
Abstract: Under development for next-generation wearable electronics are flexible, knittable, and wearable energy-storage devices with high energy density that can be integrated into textiles. Herein, knittable fiber-shaped zinc-air batteries with high volumetric energy density (36.1 mWh cm-3 ) are fabricated via a facile and continuous method with low-cost materials. Furthermore, a high-yield method is developed to prepare the key component of the fiber-shaped zinc-air battery, i.e., a bifunctional catalyst composed of atomically thin layer-by-layer mesoporous Co3 O4 /nitrogen-doped reduced graphene oxide (N-rGO) nanosheets. Benefiting from the high surface area, mesoporous structure, and strong synergetic effect between the Co3 O4 and N-rGO nanosheets, the bifunctional catalyst exhibits high activity and superior durability for oxygen reduction and evolution reactions. Compared to a fiber-shaped zinc-air battery using state-of-the-art Pt/C + RuO2 catalysts, the battery based on these Co3 O4 /N-rGO nanosheets demonstrates enhanced and stable electrochemical performance, even under severe deformation. Such batteries, for the first time, can be successfully knitted into clothes without short circuits under external forces and can power various electronic devices and even charge a cellphone.
309 citations
TL;DR: In this article, a new Z-scheme mes-Sn3O4/g-C3N4 heterostructure was obtained, compared with single g-C 3N4, which exhibits more superior photocatalytic performance for degrading and mineralizing tetracycline hydrochloride in water.
Abstract: Antibiotic drugs have become the important organic pollutants in the water resources, the high-efficient removal of which is one of the foremost works for protecting water environment. The new Z-scheme mes-Sn3O4/g-C3N4 heterostructure was obtained in present work, compared with single g-C3N4, which exhibits more superior photocatalytic performance for degrading and mineralizing tetracycline hydrochloride in water. The investigations of microstructure, physical properities and photoelectrochemical behaviors indicate that the modification effect mesoporous Sn3O4 on the surface of g-C3N4 nanosheets fabricates close heterostructure, which enlarges distinctly the specific surface area and improves dramatically the separation efficiency of charge carriers. Furthermore, the possible photocatalytic reaction mechanisms including transfer behaviors of charge carriers, generation of reactive species, degradation intermediate products of TC-HCl are also revealed in depth.
305 citations
TL;DR: This work creates a new pathway to fabricate 2D meso/microporous structured carbon architectures for bifunctional oxygen electrodes in rechargeable Zn-air battery as well as opens avenues to the scale-up production of rationally designed heteroatom-doped catalytic materials for a broad range of applications.
Abstract: Two types of templates, an active metal salt and silica nanoparticles, are used concurrently to achieve the facile synthesis of hierarchical meso/microporous FeCo-Nx -carbon nanosheets (meso/micro-FeCo-Nx -CN) with highly dispersed metal sites. The resulting meso/micro-FeCo-Nx -CN shows high and reversible oxygen electrocatalytic performances for both ORR and OER, thus having potential for applications in rechargeable Zn-air battery. Our approach creates a new pathway to fabricate 2D meso/microporous structured carbon architectures for bifunctional oxygen electrodes in rechargeable Zn-air battery as well as opens avenues to the scale-up production of rationally designed heteroatom-doped catalytic materials for a broad range of applications.
297 citations
TL;DR: This novel synthetic route opens a new dimension of control in the synthesis of 2D metals, enabling new kinds of mesoporous architectures with abundant catalytically active sites.
Abstract: Two-dimensional (2D) metals are an emerging class of nanostructures that have attracted enormous research interest due to their unusual electronic and thermal transport properties. Adding mesopores...
287 citations
TL;DR: Red blood cell like-mesoporous carbon hollow microspheres (RBC-PCHMs) have been synthesized by modified stober method with following pyrolysis and etching procedures.
273 citations
TL;DR: In this paper, a straightforward coassembly strategy is demonstrated to synthesize Pt sensitized mesoporous WO3 with crystalline framework through the simultaneous coassembly of amphiphilic poly(ethylene oxide)-b-polystyrene, hydrophobic platinum precursors, and hydrophilic tungsten precursor.
Abstract: In this study, a straightforward coassembly strategy is demonstrated to synthesize Pt sensitized mesoporous WO3 with crystalline framework through the simultaneous coassembly of amphiphilic poly(ethylene oxide)-b-polystyrene, hydrophobic platinum precursors, and hydrophilic tungsten precursors. The obtained WO3/Pt nanocomposites possess large pore size (≈13 nm), high surface area (128 m2 g−1), large pore volume (0.32 cm3 g−1), and Pt nanoparticles (≈4 nm) in situ homogeneously distributed in mesopores, and they exhibit excellent catalytic sensing response to CO of low concentration at low working temperature with good sensitivity, ultrashort response-recovery time (16 s/1 s), and high selectivity. In-depth study reveals that besides the contribution from the fast diffusion of gaseous molecules and rich interfaces in mesoporous WO3/Pt nanocomposites, the partially oxidized Pt nanoparticles that chemically and electronically sensitize the crystalline WO3 matrix, dramatically enhance the sensitivity and selectivity.
TL;DR: Based on eutectic reaction and dealloying inheritance effect, a novel Ni-Fe-O-based composite with a unique mesoporous nanowire network structure is designed and synthesized in this paper.
Abstract: The development of efficient and abundant water oxidation catalysts is essential for the large-scale storage of renewable energy in the form of hydrogen fuel via electrolytic water splitting, but still remains challenging. Based upon eutectic reaction and dealloying inheritance effect, herein, novel Ni-Fe-O-based composite with a unique mesoporous nanowire network structure is designed and synthesized. The composite exhibits exceptionally low overpotential (10 mA cm−2 at an overpotential of 244 mV), low Tafel slope (39 mV dec−1), and superior long-term stability (remains 10 mA cm−2 for over 60 h without degradation) toward oxygen evolution reaction (OER) in 1 m KOH. Moreover, an alkaline water electrolyzer is constructed with the Ni-Fe-O composite as catalyst for both anode and cathode. This electrolyzer displays superior electrolysis performance (affording 10 mA cm−2 at 1.64 V) and long-term durability. The remarkable features of the catalyst lie in its unique mesoporous nanowire network architecture and the synergistic effect of the metal core and the active metal oxide, giving rise to the strikingly enhanced active surface area, accelerated electron/ion transport, and further promoted reaction kinetics of OER.
TL;DR: In this paper, a mesoporous conjugate adsorbent (MCA) was fabricated by directly anchoring the organic ligand of 2-hydroxyacetophenone-4N-pyrrolidine thiosemicarbazones (HAPT) onto highly ordered ZSM-5 for efficient and selective mercury (Hg(II)) ions capturing from aqueous solution.
TL;DR: This work designs and synthesizes a novel nanostructure of Fe-doped CoP hollow triangle plate arrays (Fe-CoP HTPAs) with unique mesoporous shells that exhibit pronounced activity for water splitting owing to the advantages of abundant active reaction sites, short electron and ion pathways, and favorable hydrogen adsorption free energy.
Abstract: Hollow nanostructures with mesoporous shells are attractive for their advantageous structure-dependent high-efficiency electrochemical catalytic performances. In this work, a novel nanostructure of Fe-doped CoP hollow triangle plate arrays (Fe-CoP HTPAs) with unique mesoporous shells is designed and synthesized through a room-temperature postsynthetic ligand exchange reaction followed by a facile phosphorization treatment. The mild postsynthetic ligand exchange reaction of the presynthesized ZIF-67 TPAs with K4 [Fe(CN)6 ] in an aqueous solution at room temperature is of critical importance in achieving the final hollow nanostructure, which results in the production of CoFe(II)-PBA HTPAs that not only determine the formation of the interior voids in the nanostructure, but also provide the doping of Fe atoms to the CoP lattice. As expected, the as-prepared mesoporous Fe-CoP HTPAs exhibit pronounced activity for water splitting owing to the advantages of abundant active reaction sites, short electron and ion pathways, and favorable hydrogen adsorption free energy (ΔGH* ). For the hydrogen and oxygen evolution reactions with the Fe-CoP HTPAs in alkaline medium, the low overpotentials of 98 and 230 mV are observed, respectively, and the required cell voltage toward overall water splitting is only as low as 1.59 V for the driving current density of 10 mA cm-2 .
TL;DR: A cluster precursor approach, resulting in minimal side product formation in the solvothermal synthesis, was used to produce DUT-60, a new crystalline framework with the highest recorded accessible pore volume surpassing all known crystallines framework materials.
Abstract: A new mesoporous metal-organic framework (MOF; DUT-60) was conceptually designed in silico using Zn4 O6+ nodes, ditopic and tritopic linkers to explore the stability limits of framework architectures with ultrahigh porosity. The robust ith-d topology of DUT-60 provides an average bulk and shear modulus (4.97 GPa and 0.50 GPa, respectively) for this ultra-porous framework, a key prerequisite to suppress pore collapse during desolvation. Subsequently, a cluster precursor approach, resulting in minimal side product formation in the solvothermal synthesis, was used to produce DUT-60, a new crystalline framework with the highest recorded accessible pore volume (5.02 cm3 g-1 ) surpassing all known crystalline framework materials.
TL;DR: In this paper, the mesoporous ZSM-5 substrate was synthesized by the direct templating technique for decolorization and minerlization of methyl orange (MO) dye effluent.
Abstract: TiO2 photocatalyst hybridized with new multilamellar vesicles (MLVs) mesoporous ZSM-5 substrate (TiO2/ZSM-5) were prepared by the direct templating technique for decolorization and minerlization of methyl orange (MO) dye effluent. The synthesized materials were characterized by X-ray diffraction (XRD), Field-emission scanning electron microscopy (FE-SEM), Fourier-transformed infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET). It was found that the specific surface area (SBET) of the synthesized TiO2/ZSM-5 was 1151 m2 g−1. The results also indicated that the zeolite structure conserves mesoporous structure after the removal of surfactant templates. Several parameters were also investigated such as the effect of catalyst types, pH, adsorption/photocatalysis phenomenon and contact time. Under 180 min solar irradiation, MO dye was efficiently decolorized and mineralized to be 99.55% and 99%, respectively, at an initial MO concentration of 20 mg L−1. Furthermore, the photocatalysis kinetic fit the pseudo-second-order model well and a great potential for saving energy associated with its recyclability. Therefore, the synthesized TiO2/ZSM-5 could be used as a promosing photocatalysis for fast removal and treatment of coloured wastewater.
TL;DR: Monolayer-ordered mesoporous carbon nanosheets (OMCNS) were prepared through confinement assembly of resol and F127 in the interlayer of montmorillonite, enabling OMCNS as excellent electrode materials for electric double layer capacitors.
Abstract: Although two-dimensional (2D) carbon materials are widely investigated, a well-defined 2D carbon nanosheet with an ordered mesostructure has rarely been realized. Monolayer-ordered mesoporous carbon nanosheets (OMCNS) were prepared through confinement assembly of resol and F127 in the interlayer of montmorillonite (MONT). The nanoscale distance of the interlayer space of MONT only allow the assembly of resol and F127 in the same plane, leading to ordered mesopores perpendicular to carbon nanosheets, and favor the formation of sp2 carbon, resulting in a high degree of graphitization. The mesopores on the carbon nanosheets provide efficient ion diffusion, and the high degree of graphitization provides a fast electron-transport route, enabling OMCNS as excellent electrode materials for electric double layer capacitors.
TL;DR: In this article, the mesoporous structure of activated biomass carbons (ABCs) was optimized to achieve high specific surface areas and mesopore structures, and the specific surface area, total pore volume, and average pore size of the activated biomass carbon were controlled by adjusting the activation temperature from 700 to 1000°C.
TL;DR: In this article, Urchin-like Co3O4 microspheres have been obtained through a two-step hydrothermal method followed by a post-calcination process and show a unique hollow structure with mesoporous nanosheets on their surface.
Abstract: Urchin-like Co3O4 microspheres have been obtained through a two-step hydrothermal method followed by a post-calcination process and show a unique hollow structure with mesoporous nanosheets on their surface. Oxygen vacancies on the ultrathin nanosheets were introduced by annealing treatment, inducing a local built-in electric field to promote the migration of Li ions by Coulomb force during cycling and leading to a superior electrochemical performance for lithium-ion batteries. The electrodes containing urchin-like mesoporous hollow Co3O4 microspheres delivered a high discharge capacity of 2164.1 mA h g−1 at 0.05 A g−1 after 100 cycles. Even at a higher current density of 1.0 A g−1, a remarkable discharge capacity of 1307.9 mA h g−1 after 1000 cycles could still be achieved.
TL;DR: The pineapple leaves are an efficient precursor for preparation of ACFs, which were successful applied as adsorbent material for removal of caffeine from the aqueous solutions and revealed that adsorption process is spontaneous, exothermic and occurs preferably via physisorption.
TL;DR: These mesoporous TiO2 nanosheets have exhibited an excellent reversible capacity and can retain at 199 mAh g-1 after numerous cycles at different current densities, demonstrating a remarkable performance for energy storage.
Abstract: Two-dimensional (2D) nanomaterials have been the focus of substantial research interest recently owing to their fascinating and excellent properties. However, 2D porous materials have remained quite rare due to the difficulty of creating pores in 2D nanostructures. Here, we have synthesized a novel type of single-layered 2D mesoporous TiO2 nanosheets with very uniform size and thickness as well as ordered mesostructure from an unprecedented hydrothermal-induced solvent-confined assembly approach. The F127/TiO2 spherical monomicelles are first formed and redispersed in ethanol and glycerol, followed by a hydrothermal treatment to assemble these subunits into single-layered 2D mesostructure owing to the confinement effect of highly adhered glycerol solvent. The obtained 2D mesoporous TiO2 nanosheets have a relative mean size at around 500 × 500 nm and can be randomly stacked into a bulk. The TiO2 nanosheets possess only one layer of ordered mesopores with a pore size of 4.0 nm, a very high surface area of 2...
TL;DR: This work demonstrates an effective strategy of engineering the yolk@shell-architectured anodes and sheds light onto harnessing the complex multistep reactions in metal sulfides to enable high-performance lithium-ion batteries.
Abstract: High-performance lithium-ion batteries are commonly built with heterogeneous composite electrodes that combine multiple active components for serving various electrochemical and structural functions. Engineering these heterogeneous composite electrodes toward drastically improved battery performance is hinged on a fundamental understanding of the mechanisms of multiple active components and their synergy or trade-off effects. Herein, we report a rational design, fabrication, and understanding of yolk@shell Bi2S3@N-doped mesoporous carbon (C) composite anode, consisting of a Bi2S3 nanowire (NW) core within a hollow space surrounded by a thin shell of N-doped mesoporous C. This composite anode exhibits desirable rate performance and long cycle stability (700 cycles, 501 mAhg–1 at 1.0 Ag–1, 85% capacity retention). By in situ transmission electron microscopy (TEM), X-ray diffraction, and NMR experiments and computational modeling, we elucidate the dominant mechanisms of the phase transformation, structural e...
TL;DR: In this paper, mesoporous gamma-aluminas (γ-Al2O3) were synthesized starting from an unusual precursor of polyoxohydroxide aluminum (POHA), which was obtained from aluminum oxidation in alkaline water-ethanol solvent in the presence of d-glucose that induces the formation of a gel, which leads to the POAH powder after ethanolic treatment.
Abstract: Mesoporous gamma-aluminas (γ-Al2O3) were synthesized starting from an unusual precursor of polyoxohydroxide aluminum (POHA). This precursor was obtained from aluminum oxidation in alkaline water-ethanol solvent in the presence of d-glucose that induces the formation of a gel, which leads to the POAH powder after ethanolic treatment. Precipitated POHAs were calcined at different temperatures (300, 400, 700 and 900 °C) resulting in the metastable γ-Al2O3 phase. Whereas at 300 °C no γ-Al2O3 phase was formed, unexpectedly, mesoporous γ-Al2O3 was obtained at 400 oC having a high specific surface area (282 m2/g) and a narrow pore size distribution. At higher temperatures, the aluminas had the expected decrease in surface area: 166 m2/g (700 °C) and 129 m2/g (900 °C), respectively. The structural change from POHA to alumina calcined at 400 oC occurs directly without the need to isolate the hydroxide or oxyhydroxide aluminum precursors. Both POHA and transition aluminas were characterized by Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD), N2 sorption and Scanning Electron Microscopy (SEM). These findings show an alternative route to produce high standard aluminas.
TL;DR: In this paper, a supported cobalt catalyst with atomically dispersed Co-N x sites (3.5wt% Co) was synthesized by hydrolysis of tetramethyl orthosilicate (TMOS) in a Zn/Co bimetallic zeolitic imidazolate framework (BIMZIF(Co,Zn)), followed by high-temperature pyrolysis and SiO 2 leaching.
TL;DR: TiO2 mesoporous crystal has been prepared by one-step corroding process via an oriented attachment (OA) mechanism with SrTiO3 as precursor and performs high activity for electrocatalytic hydrogen evolution reaction (HER) in alkaline solution.
Abstract: TiO2 mesoporous crystal has been prepared by one-step corroding process via an oriented attachment (OA) mechanism with SrTiO3 as precursor. High resolution transmission electron microscopy (HRTEM) and nitrogen adsorption–desorption isotherms confirm its mesoporous crystal structure. Well-dispersed ruthenium (Ru) in the mesoporous nanocrystal TiO2 can be attained by the same process using Ru-doped precursor SrTi1–xRuxO3. Ru is doped into lattice of TiO2, which is identified by HRTEM and super energy dispersive spectrometer (super-EDS) elemental mapping. X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance spectroscopy (EPR) suggest the pentavalent Ru but not tetravalent, while partial Ti in TiO2 accept an electron from Ru and become Ti3+, which is observed for the first time. This Ru-doped TiO2 performs high activity for electrocatalytic hydrogen evolution reaction (HER) in alkaline solution. First-principles calculations simulate the HER process and prove TiO2:Ru with Ru5+ and Ti3+ h...
TL;DR: In this paper, it was demonstrated that the incorporation of alkali metal dopants in mesoporous TiO2 can effectively modulate electronic conductivity and improve the charge extraction process by counterbalancing oxygen vacancies acting as nonradiative recombination centers.
Abstract: Facile electron injection and extraction are two key attributes desired in electron transporting layers to enhance the efficiency of planar perovskite solar cells. Herein it is demonstrated that the incorporation of alkali metal dopants in mesoporous TiO2 can effectively modulate electronic conductivity and improve the charge extraction process by counterbalancing oxygen vacancies acting as nonradiative recombination centers. Moreover, sulfate bridges (SO42-) grafted on the surface of K-doped mesoporous titania provide a seamless integration of absorber and electron-transporting layers that accelerate overall transport kinetics. Potassium doping markedly influences the nucleation of the perovskite layer to produce highly dense films with facetted crystallites. Solar cells made from K:TiO2 electrodes exhibit power conversion efficiencies up to 21.1% with small hysteresis despite all solution coating processes conducted under ambient air conditions (controlled humidity: 25-35%). The higher device efficiencies are attributed to intrinsically tuned electronic conductivity and chemical modification of grain boundaries enabling uniform coverage of perovskite films with large grain size.
TL;DR: In this paper, a facial, one-step soft templating method to synthesize the hollow mesoporous g-C3N4 spheres with high surface area and high porosity was developed, which took advantage of both supramolecular assembly of cyanuric acid and melamine through hydrogen bonds and the structure-directing character of ionic liquid.
TL;DR: A review of recent literature on pristine and specifically functionalized mesoporous silica-based materials or "designer silicates" used as adsorbents for aqueous pollutants removal and water treatment is presented in this paper.
TL;DR: In this article, the Fe-doped NiO mesoporous nanosheets array on Ni foam with different Fe dopant content (Fex%-NiO/NF) was synthesized by a facile solvothermal synthesis in mixed solvents of deionized water and methanol and subsequent anneal in air.