Two-dimensional (2D) mesoporous nanomaterials are required in catalysis, separation, adsorption, and energy storage fields due to their outstanding mass transfer performance. However, their fabrication via the 'bottom up' strategy has been rarely reported and is limited by the difficulties in obtaining a versatile and accessible structure-directing agent. Here, ultrathin mesoporous silica nanosheets (MSN) were successfully synthesized by employing acidified g-C3N4 as a structural directing agent owing to its natural layered structure, stoichiometric solubility, and amphiphilicity. The thickness of MSN is readily adjustable by tuning the dosage of acidified g-C3N4 during the fabrication process, and when the mass ratio of silica/acidified-g-CzN4 is 10, the thickness of the MSN is 6-9 nm. TEM, SAXRD, and BET analysis demonstrated the mesoporous characteristics of MSN with a long-range ordered hexagonal arrangement symmetry, a uniform pore size distribution around 2.9 nm, and high BET surface areas of 1000-1150 m2 g-1. The superior mass-transfer performance of MSN in catalysis applications, which was derived from its special structure, was confirmed by the outstanding methane combustion activity of MSN supported Co3O4 catalysts. This work provides a controllable and scalable 'bottom up' fabrication method for 2D porous material, and also opens up an alternative application for g-C3N4.

Introducing high-index facet into crystals is a promising way to provide additional catalytically active sites for boosting intrinsic activity. This work presents a simple one-pot annealing way to fabricate highly photoactive pristine polyhedral α-Fe2O3 single crystal, using melamine as solvent and coordination agent. The HR-TEM results realized that the as-prepared sample was enclosed by high-index {116} facet, which was always not presented in traditional hydrothermal method. The photoelectrochemical (PEC) measurements have been carried out and showed that the polyhedron samples exhibited significantly enhancement in the photocurrent density, which is nearly 28 times higher than that of the α-Fe2O3 prepared without melamine under the same conditions. Our work may guide future designs for high-index crystal facet exposed of metal oxides and suggest paths for further improvements to allow technological development and use.

Novel composites composed of graphitic carbon nitride (GCN) and p-type semiconductor of NiO nanosheet arrays were fabricated for the first time and demonstrated to be efficient photocathodes for enhancing charge separation and hole transfer.

We present a novel method to prepare mesoporous materials via in situ self-assembly of graphitic carbon nitride nanosheets and silica nanoparticles. Combining the advantages of g-C3N4 nanosheets and mesoporous structure, the as-prepared materials exhibit superior adsorption capabilities for heavy metal ions and organic pollutants.

AlPO4-5 aluminophosphate molecular sieve with AFI topology has been successfully synthesized by microwave irradiation under solvent-free conditions. The key influential factors controlling the crystallization of AFI structure were thoroughly investigated. The optimum synthetic conditions of this material are as follows: the initial composition is 1.0Al2O3: 3.0P2O5: 2.0HF: 8.0TEABr(tetraethylammonium bromide): 125C, aluminum isopropoxide is the best aluminum source, and activated carbon needs to be pretreated before used as the reaction medium and hard template. The resultant AlPO4-5 molecular sieves were characterized by X-ray diffraction (XRD), N2 physisorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results reveal that the obtained samples exhibit hierarchically porous characteristic.

Nitrogen-containing activated carbon fibers (N-ACFs) with ultra-high specific surface area and abundance micropores are synthesized from natural silk fibers. The N-ACFs exhibited the CO2 uptake of 7.0mmol/g and 4.8mmol/g at 0°C and 25°C, 101kPa. These outstanding features as a CO2 solid adsorbent were mostly attributed to the materials׳ physical properties (microporosity) in addition to its high content of basic nitrogen species.

Hierarchically structured SAPO-5 molecular sieve was synthesized by microwave-assisted ionothermal method in eutectic mixture solvent. Their porous texture and acid properties were characterized by nitrogen physisorption, SEM, TEM and NH 3 -TPD. The results show that the mesoporous volume of SAPO-5 can be tuned via simply varying the degree of supersaturation, the type of mineralizer or replacing partly succinic acid with sebacic acid. A lower degree of supersaturation and using ammonium fluoride as a mineralizer favor the synthesis of SAPO-5 with large mesoporous volume. Notably, the introduction of sebacic acid can lead to three-level micro-meso-macroporous structure (sample C1). Five typical samples were selected as catalysts and tested in the alkylation of benzene with benzyl alcohol. Among all catalysts, the sample C1, whose aspect ratio is the lowest, exhibited the best catalytic activity, giving a 91 % benzyl alcohol conversion. The diffraction peak intensity ratio of I 002 /I 100 was proposed to be a good indicator in fabricating a highly active SAPO-5 catalyst for this reaction.

In comparison to the conventional high temperature (≥1,300 °C) preparation conditions, a series of Ruddlesden–Popper (R–P) type layered perovskite LaxCa3−xMn2O7 (x = 0.8, 1.0, 1.2, 1.5, 2.0, 2.5, and 3.0) were synthesized at 700 °C by an improved method based on the strategy involving the “inductive effect of Cl”. XRD results revealed the unitary R–P type layered perovskite structure in the samples of x = 0.8, 1.0, 1.2, and 3.0. While in the samples of x = 1.5, 2.0, and 2.5, the layered perovskite phase and lanthanum oxide phase coexisted, which resulted in their poor redox properties. XPS and H2-TPR results demonstrated that the redox properties of LaxCa3−xMn2O7 were correlated with its structural integrity and purity and influenced by the x value. The sample of x = 1.2 gave the highest methane combustion activity with T 50 = 449 °C, and the sample of x = 2.0 showed the lowest activity with T 50 = 538 °C, which was in accordance with the XPS and H2-TPR results. The specific surface areas of LaxCa3−xMn2O7 depended on the x value monotonically, and the sample of x = 0.8 presented the highest surface area value (33.59 m2 g−1).

We propose an efficient method to synthesize large-scale soluble acidified graphitic carbon nitride (g-C3N4). The as-prepared material exhibits the characteristics of a poly-ammonium salt and is soluble in several solvents with good dissolution-recrystallization reversible equilibrium. The pH value-and temperature-dependent solubility of the acidified g-C3N4 facilitates its separation and purification. After dissolution, acidified g-C3N4 forms isolated ultrathin nanosheets, making it an ideal precursor for large quantities of g-C3N4 nanosheets. This study raises the possibility of liquid assembly for g-C3N4 nanosheets based composite materials, expanding the functionalization and application of g-C3N4.

CuO-ZnO-Al2O3 and graphene nanosheet (GNS) were synthesized by coprecipitation route and reduction of exfoliated graphite oxides method, respectively. GNS modified CuO-ZnO-Al2O3 nanocomposites were synthesized by high energy ball milling method. The structure, morphology, and character of the synthesized materials were studied by BET, XRD, TEM, and H-2-TPR. It was found that by high energy ball milling method the CuO-ZnO-Al2O3 nanoparticles were uniformly dispersed on GNS surfaces. The catalytic performance for the methanol synthesis from CO2 hydrogenation was also tested. It was shown experimentally that appropriate incorporation of GNS into the CuO-ZnO-Al2O3 could significantly increase the catalyst activity for methanol synthesis. The 10 wt.% GNS modified CuO-ZnO-Al2O3 catalyst gave a methanol space time yield (STY) of 92.5% higher than that on the CuO-ZnO-Al2O3 catalyst without GNS. The improved catalytic performance was attributed to the excellent promotion of GNS to dispersion of CuO and ZnO particles.

Correction for 'Oxygen-enriched activated carbons from pomelo peel in high energy density supercapacitors' by Chao Peng et al., RSC Adv., 2014, 4, 54662–54667.

Carbon dioxide reforming of methane to synthesis gas was investigated with a series of Ni catalysts supported on Hydroxyapatite ( HAp) prepared by chemical precipitation at low temperature. The structure and properties of the catalysts were characterized using BET, H2-TPR, XRD, SEM, FT-IR , TEM and TG-DTA techniques. The 13% NiO/HAp showed the highest activity for catalytic carbon dioxide reforming of methane to synthesis gas. Under the condition of an atmospheric pressure at 850℃ and a gas hour space velocity ( GHSV) of 3. 6 í104 mL/( h·gcat ), the conversion of CH4 and CO2 over 13% Ni/HAp catalyst remained almost constant, at about 72% and 83%, for 10 h, respectively, which was ascribed to strong metal-support interaction. Most of the carbonaceous deposits on the catalyst surface were in whisker form, which did not cover the active sites and then had limited influence on the catalyst activity and stability.

Pomelo peel as biomass-derived porous activated carbon is used for the preparation of a high energy density symmetric supercapacitor.

Oxidative coupling of methane (OCM) has been studied over a mixed catalyst constituted by Na2WO4-Mn/SiO2 (W) and BaCl2-TiO2-SnO2 (B). The effects of reaction temperature, gas hourly space velocity (GHSV) and CH4/O-2 ratio on catalytic performance were systematic investigated. Compared with the single component counterpart, the results indicated that ethylene yield was significantly enhanced over the mixed catalysts. When the BaCl2-TiO2-SnO2/Na2WO4-Mn/SiO2 (B/W) ratio was controlled at 1/5 (v/v), the ethylene yield reached 22.2 %, which was 7.1 %, 2.1 % higher than the single Na2WO4-Mn-SiO2, BaCl2-TiO2-SnO2 catalyst, respectively. Besides, the ethylene yield was higher than 20 % over the mixed catalyst in wide reaction condition range.

The performance of MCl2-TiO2-SnO2(M=Mg,Ca,Sr,Ba) catalysts in oxidative coupling of methane reaction has been investigated.The catalysts were prepared by grinding method,and characterized by BET,XRD,XPS and CO2-TPD,respectively.The distribution of surface basicity strength is varied with the changing of M2+ in the catalysts.The more weak basic sites on catalyst surface are crucial for the activation of methane;while the strong basic sites bring the loss of active sites on catalyst surface.In addition,although the basic site can prompt the conversion of methane,it can also bring the deep oxidative of ethylene.The lattice oxygen is selective to ethy-lene product generation,and the selectivity to ethylene increase with increasing relative concentration of surface lattice oxygen.

Carbon nanotubes (CNTs) supported Pd nanoparticle (NP) catalysts (Pd/CNTs) were prepared by a green and facile synthesis method based on hydrogen-bonding self-assembly. The size and loading of Pd NPs on catalysts were easily controlled by tuning both the relative amount of citrate to Pd salt in the solution and the relative amount of Pd NPs to CNTs. The size of Pd NPs on as-prepared catalysts can be tuned in the range of 3–6 nm, and Pd loading can be controlled in the range of 0–19 wt%. The catalysts were characterized by Brunauer–Emmett–Teller measurement, x-ray diffraction spectroscopy, and x-ray photoelectron spectroscopy. The performance of Pd/CNTs catalysts was evaluated in the hydrogenation of nitrobenzene. Compared with the catalysts prepared by the impregnation method or supported on conventional supports, Pd/CNTs catalysts show relatively higher activity and selectivity. The recyclability tests indicate that the Pd/CNTs catalysts can be used at least five times without significant loss in activity and selectivity.

At atmospheric pressure, FeAlPO-5 molecular sieve with hierarchical micro- and meso-porous structure has been ionothermally synthesized by microwave heating with eutectic mixture as the solvent. Among the synthesis parameters investigated, the ratio of P2O5/Al2O3, aluminum source, and heating methods significantly affected the mesoporosity of FeAlPO-5 molecular sieve. N-2 Physisorption, SEM and TEM characterizations showed that the resultant material possessed inter- and intra-crystalline mesopores simultaneously. The larger intercrystalline mesopores in size resulted from the intercrystalline void space between bar crystals and nanoparticles. The calcination removed the organic species embedded in the crystals of FeAlPO-5 molecular sieve, leading to the formation of smaller intracrystalline mesopores. The catalytic properties of hierarchical FeAlPO-5 molecular sieve were investigated in the hydroxylation of phenol with microporous FeAlPO-5 as a reference. The results showed that the catalytic performance of the former catalyst was superior to the latter. (C) 2013 Elsevier Inc. All rights reserved.

Various CuO-ZnO/Al2O3 catalysts have been synthesized by citric acid sol-gel auto-combustion method and their performances for methanol synthesis from CO2 hydrogenation have been investigated.The effects of citric acid /nitrate ratio on physicochemical,morphologies and catalytic properties were studied by BET,XRD,SEM,XPS and H2-TPR.Catalytic activities of the prepared catalysts for methanol synthesis were tested in fixed-bed flow reactor.The results indicated that when 100% of stoichiometric amount of citric acid was used,the CuO-ZnO/Al2O3 catalyst exhibited an optimum catalytic behavior.The catalyst showed relatively smaller particle size,higher surface area and more uniform Cu dispersion.

In comparison to the conventional high-temperature (>= 1300 degrees C) preparation methods, a novel strategy for the synthesis of a Ruddlesden-Popper (R-P) type layered perovskite La3Mn2O7+delta (LLM) at a relatively low temperature (700 degrees C) was proposed. The conventional perovskite LaMnO3 (LM) and the nominal La3Mn2O7+delta (NLM) synthesized by the citric acid sol-gel method were compared. Density functional theory calculations were performed to expound the synthesis strategy. The results of X-ray diffraction and high-resolution transmission electron microscopy demonstrated the formation of an R-P type layered perovskite crystal structure in the LLM samples. The results of X-ray photoelectron spectroscopy and hydrogen-temperature-programmed reduction showed that the LLM sample calcined at 700 degrees C possessed richer and more stable active lattice oxygen species than the other samples because of its two-dimensionally ordered loose intercalated structure. Thus, the LLM samples exhibited excellent thermal stability and higher activity for methane combustion than the LM and NLM samples. After calcination at 1000 degrees C, the LLM samples still had a relatively higher specific surface area (15.28 m(2) g(-1)) than the LM samples (6.64 m(2) g(-1)).