A series of Al-SBA-15 materials with different Si/Al ratios have been prepared via a post-alumination procedure. The results show that Al species can be introduced into the SBA-15 framework. Only the medium acid sites can be observed on the Al-SBA-15 samples, and the number of acid sites decreases with the increase of the Si/Al ratio. The hydroisomerization activities of n-dodecane over 1% Pt/Al-SBA-15-n catalysts increase with the number of acid sites, and the largest isomers yield reaches to 51%. It suggests that the Al-SBA-15 material is a suitable acid component for bifunctional catalysts for hydroisomerization of long chain n-paraffins.

Cong Nie;Limin Huang;东元 赵;Quanzhi Li

Catalysis Letters

2001-1

Porous carbon nitride (CN) spheres with partially crystalline frameworks have been successfully synthesized via a nanocasting approach by using spherical mesoporous cellular silica foams (MCFs) as a hard template, and ethylenediamine and carbon tetrachloride as precursors. The resulting spherical CN materials have uniform diameters of ca. 4 μm, hierarchical three-dimensional (3-D) mesostructures with small and large mesopores with pore diameters centered at ca. 4.0 and 43 nm, respectively, a relatively high BET surface area of ~550 m²/g, and a pore volume of 0.90 cm³/g. High-resolution transmission electron microscope (HRTEM) images, wide-angle X-ray diffraction (XRD) patterns, and Raman spectra demonstrate that the porous CN material has a partly graphitized structure. In addition, elemental analyses, X-ray photoelectron spectra (XPS), Fourier transform infrared spectra (FT-IR), and CO₂ temperature-programmed desorption (CO₂-TPD) show that the material has a high nitrogen content (17.8 wt%) with nitrogen-containing groups and abundant basic sites. The hierarchical porous CN spheres have excellent CO₂ capture properties with a capacity of 2.90 mmol/g at 25 °C and 0.97 mmol/g at 75 °C, superior to those of the pure carbon materials with analogous mesostructures. This can be mainly attributed to the abundant nitrogen-containing basic groups, hierarchical mesostructure, relatively high BET surface area and stable framework. Furthermore, the presence of a large number of micropores and small mesopores also enhance the CO₂ capture performance, owing to the capillary condensation effect.

Qiang Li;Jianping Yang;Dan Feng;Zhangxiong Wu;Qingling Wu;Sung Soo Park;Chang Sik Ha;东元 赵

Nano Research

2010

Nanoporous niobium phosphate (Nb-P) electrolyte membranes were prepared by dry pressing Nb-P nanoparticles for low temperature fuel cells. Highly dispersible Nb-P nanoparticles were synthesized by dispersing Nb-P precursor in furfuryl alcohol, which was polymerized to poly(furyfuryl alcohol) as a space-confinement additive during calcination. SEM, TEM and a range of spectroscopies were used to characterize Nb-P particles and membranes (discs). Nanoporous Nb-P membrane exhibited high proton conductivity (17.4mScm^-1), low methanol permeability (1.1×10^-7cm²s^-1) whereas Nb-P membrane prepared from Nb-P particles synthesized without adding furfuryl alcohol had poor proton conductivity (0.341mScm^-1) and high methanol permeability (3.13×10^-5cm²s^-1). The cell prepared with nanoporous Nb-P membrane showed good cell performance when operated as both H₂-O₂ fuel cell at room temperature and as DMFC at 60°C; also this cell performs better than the cell with Nafion membrane at a current density of <72mAcm^-2, and its peak power density is comparable to the cell with Nafion membrane.

Zhanli Chai;Dehua Dong;Cheng Wang;Hongjie Zhang;Paul A. Webley;东元 赵;Huanting Wang

Journal of Membrane Science

2010-7

Porous silica, niobia, and titania with three-dimensional structures patterned over multiple length scales were prepared by combining micromolding, polystyrene sphere templating, and cooperative assembly of inorganic sol-gel species with amphiphilic triblock copolymers. The resulting materials show hierarchical ordering over several discrete and tunable length scales ranging from 10 nanometers to several micrometers. The respective ordered structures can be independently modified by choosing different mold patterns, latex spheres, and block copolymers. The examples presented demonstrate the compositional and structural diversities that are possible with this simple approach.

Peidong Yang;Tao Deng;东元 赵;Pingyun Feng;David Pine;Bradley F. Chmelka;George M. Whitesides;Galen D. Stucky

Science

1998-12-18

Titanium-containing mesoporous molecular sieves including periodic mesoporous silicas (SBA-15-type) and organosilicas (PMO-type) can be assembled by using mixed inorganic acid-base pairs (TiCl₄ and tetrabutyl titanate) or a single inorganic TiCl₃ as the titanium sources and tetraethoxysilane and/or 1,2-bis(triethoxysilyl)ethane as the silica sources and triblock copolymer as the structure-directing agent in acidic media through the hydrothermal method. Characterization using XRD, nitrogen sorption isotherms, UV-vis, FT-IR and NMR techniques reveals that the Ti-containing mesoporous materials possess ordered 2D hexagonal mesostructures, high surface areas (421-1070 m²/g), uniform pore sizes (5.1-8.0 nm), large pore volumes (0.5-1.3 cm³/g), and tetrahedrally incorporated titanium (IV) species in the silica network. The maximum incorporated Ti content is about 0.34 wt% for the ordered mesostructure regardless of the titania and silica sources and the initial Si/Ti ratio.

Huaqin Chu;Ying Wan;东元 赵

Catalysis Today

2010-10-30

Due to highly tunable metallic compositions and surface functional groups, MXenes have attracted significant interests for a wide range of applications, such as energy storage, electromagnetic interference shielding, sensors, and biomedicine. With the introduction of porous structures, which have unique advantages in tuning the conductivity and dielectric constant, adjusting the ion/guest and even electromagnetic wave transport, and also directing the loading and distribution of other functional materials, porous MXenes hold great potential in profoundly enhancing their properties. We have surveyed rapidly increasing efforts in the design and synthesis of porous MXenes with advantageous structures for diverse applications, especially in the last three years. Here we classify Porous MXenes into four categories according to their formation routes, including (i) assembly by MXenes, (ii) depositing or inserting MXenes into porous substrates, (iii) loading or coating functional porous materials on the surface of MXenes, and (iv) creating in-plane pores within MXenes. Then we summarize the primary synthetic methods for each kind of porous MXenes and discuss their applications for pseudo-capacitors, lithium/sodium batteries, lithium-sulfur batteries, electromagnetic interference shielding and adsorption, piezoresistive sensors, and cancer therapy. A particular emphasis is on the formation mechanisms of different porous structures and the detailed composition-structure-property relationships in related applications. We lastly conclude with a brief perspective on future opportunities and challenges.

Fanxing Bu;Moustafa M. Zagho;Yasseen Ibrahim;Bing Ma;Ahmed Elzatahry;东元 赵

Nano Today

2020-2

Potassium permanganate adsorbed on alumina selectively oxidizes arenes at the benzylic position. If the benzyl carbon is secondary, ketones are obtained in good yields; alcohols are produced if the benzylic position is tertiary. Benzopyranoid and benzofuranoid systems exhibit highly selective oxidation patterns. Decarboxylation occurs when phenylacetic acid is oxidized, but not when the corresponding ester, ethyl phenylacetate, is oxidized to ethyl benzoylformate.

东元 赵;D. G. Lee

Synthesis

1994

Large-pore periodic mesoporous organosilica (PMO) hollow spheres with controllable pore size and high pore volume (2.5 cm³ g^-1) were successfully synthesized at low-temperature (∼15 °C) by using the triblock copolymer Pluronic F127 as a template and 1,3,5-trimethylbenzene (TMB) as a swelling agent in the presence of inorganic salt (KCl). Transmission electron microscopy (TEM) measurements show that the PMO hollow spheres are uniform and well dispersed, and the composites have a large wall thickness. The influence of TMB, KCl, CTAB contents and media acidity on the mesostructure was systematically studied. The pore size (9.8-15.1 nm) of the hollow spheres can be gradually expanded by increasing TMB content together with a relatively high acidity. By controlling the content of CTAB, successive structural transformation from hollow sphere to wormlike mesostructure and eventually to ordered body-centered cubic (space group of Im-3m) mesostructure is observed. Our results reveal that the hydrophobicity of bis(triethoxysilyl)ethane (BTSE) and low-temperature approach contribute to the slow hydrolysis rate of silica precursors, which leads to weak interaction between individual TMB/F127 micelles and silicate oligomers. Furthermore, the salting-out effect of KCl may influence the swelling capacity of individual micelles as well as decrease the critical micelle concentration and critical micelle temperature, resulting in the formation of PMO hollow spheres from the assembly of individual TMB/F127 micelles with silicate oligomers. The composites exhibit efficient adsorption capacity (703 mg g^-1) for toluene, suggesting they are a potentially useful adsorbent for removal of volatile organic compounds. The PMO hollow spheres allow biomolecules with large molecular weight to diffuse in, and show superior encapsulation capacity of bovine serum albumin (BSA) molecules (∼585 mg g^-1) over other porous materials.

Na Hao;Huanting Wang;Paul A. Webley;东元 赵

Microporous and Mesoporous Materials

2010-8

Multimodal combinatorial therapy merges different modes of therapies in one platform, which can overcome several clinical challenges such as premature drug loss during blood circulation and significantly improve treatment efficiency. Here we report a combinatorial therapy nanoplatform that enables dual photothermal therapy and pH-stimulus-responsive chemotherapy. By super-assembly of mesoporous silica nanoparticles (MSN) with metal-phenolic networks (MPN), anti-cancer drugs can be loaded in the MSN matrix, while the outer MPN coating allows dual photothermal and pH-responsive properties. Upon near-infrared light irradiation, the MSN@MPN nanoplatform exhibits excellent photothermal effect, and demonstrates outstanding pH-triggered drug release property. In vitro cell experiments suggest the MSN@MPN system exhibits superior biocompatibility and can effectively kill tumor cells after loading anti-cancer drugs. Consequently, the MSN@MPN system shows promising prospects in clinical application for tumor therapy. [Figure not available: see fulltext.].

Bo Yang;Shan Zhou;Jie Zeng;Liping Zhang;Runhao Zhang;Kang Liang;Lei Xie;Bing Shao;Shaoli Song;Gang Huang;东元 赵;Pu Chen;Biao Kong

Nano Research

2020-4-1

N,N′-diureylenepiperazine-bridged periodic mesoporous organosilicas (PDPMOs) have been successfully synthesized through co-condensation of bissilylated N,N′-diureylenepiperazine (BPDU) and tetraethyl orthosilicate (TEOS), using a triblock copolymer (Pluronic P123) as a structure-directing agent in acidic conditions with various BPDU to TEOS ratios. These PMOs were characterized by small angle X-ray scattering (SAXS), N₂ adsorption-desorption measurements, Fourier-transform infrared (FT-IR), solid-state ²⁹Si MAS and ¹³C CP-MAS NMR spectroscopy, transmission electron (TEM) and scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). It was found that the organic functionalities could be introduced at a maximum of 30 mol% in the wall structure of the diureylenepiperazine-bridged periodic mesoporous organosilica (PDPMO-30) with respect to the total silicon content. The PDPMO-30 was thermally stable up to 230 °C. The PDPMOs have an ordered mesostructure, a high surface area (ranging from 663 to 316 m² g ^-1), a medium pore volume (1.26-0.66 cm³ g^-1), and uniform pore sizes (7.7-5.4 nm). To test a potential application of the PDPMO, in vitro assays of captopril or 5-flurouracil adsorption and delivery were carried out at pH 7.4. Due to the presence of hydrophilic urea moieties within the wall structure, the materials were shown to be particularly suitable for adsorption and desorption of drugs and could be utilized for controlled drug delivery.

Surendran Parambadath;Vijay Kumar Rana;东元 赵;Chang Sik Ha

Microporous and Mesoporous Materials

2011-5