The synthesis of crystalline mesoporous CdS semiconductor nanoarrays through a SNA-15 silica template technique was reported. Cadmium thioglycolate was used as a precursor as its in-situ decomposition to form CdS nanocrystallites provides an effective solution to the channel-clogging problem. These mesoporous semiconductor nanoarrays will provide opportunities for new applications as advanced materials and systematic studies of the transport and optical properties of these wires are currently in progress.

Feng Gao;Qingyi Lu;东元 赵

Advanced Materials

2003-5-2

Iron-nitrogen-carbon (Fe-N-C) materials featuring Fe-N₄ moieties are promising candidates to replace commercial Pt/C catalysts for the oxygen reduction reaction (ORR). Here we report a novel Mn-Fe-N/S@mC catalyst comprising atomically dispersed Fe-N₄ sites and a trace amount of Mn-N₂S₂ sites, which are homogeneously anchored on an ordered mesoporous graphitic carbon framework. This dual-metal catalyst is realized based on the chemical conversion of self-assembled Mn_0.43Fe_2.57O₄ nanocrystal supracrystals, with the dual metal sites and the graphitic framework derived from nanocrystal cores and the associated capping ligands, respectively. When evaluated as electrocatalysts for the ORR, Mn-Fe-N/S@mC exhibits excellent catalytic activity in alkaline media, outperforming conventional Pt/C and most non-precious-metal catalysts reported previously. Notably, the synergistic effect of having Fe and Mn together improves the catalytic activity by a factor of ~ 5. To better understand the high efficiency of Mn doping in enhancing the activity of Fe-N₄ sites, density functional theory calculations were carried out, revealing that the synergistic interaction between the dual metal sites reduces the *OH reduction energy barrier during the oxygen reduction pathway.

Biwei Wang;Jinxiang Zou;Xiaochen Shen;Yuchi Yang;Guangzhi Hu;Wei Li;Zhenmeng Peng;Dustin Banham;Angang Dong;东元 赵

Nano Energy

2019-9

A facile synthesis method was developed to form a nanoporous metal oxide layer using poly(furfuryl alcohol) (PFA) as a thermosetting polymer template. A nanoporous Ce_0.8Sm_0.2O_1.9 (SDC) layer with high sinterability was prepared on an anode-supported electrolyte film at 900 °C, and used as a sinter-active layer in cell fabrication to improve the interface between the inert electrolyte surface and the cathode layer of a solid oxide fuel cell (SOFC). The resulting saw-like interface improved the maximum powder density of the cell by 51% at 600 °C and 162% at 500 °C compared with that of the unmodified cell. The cell with the saw-like electrolyte-cathode interface exhibited lower electrode polarization resistance than those reported in the literature, and such improvement was much more significant at reduced operating temperatures (400-500 °C). Our study shows that the operating temperature of solid oxide fuel cells can be substantially lowered by simply improving the electrode-electrolyte interfaces.

Dehua Dong;Dan Li;Xinyi Zhang;Zhanli Chai;Kun Wang;Chun Zhu Li;东元 赵;Huanting Wang

Journal of Materials Chemistry

2010

In the present work, mesoporous silica supported heteropolyacid salts were studied systematically for glycerol acetalization with formaldehyde. Attention was focused on finding an appropriate loading of Cs_2.5H_0.5PW₁₂O₄₀ (Cs_2.5) on mesoporous silica supports and studying the influence of the architecture of mesoporous silica on activity. Supported Cs_2.5H_0.5PW₁₂O₄₀ on 2D (SBA-15) and 3D (KIT-6 and SBA-16) pore lattice mesoporous silicas have been compared. The activity of all supported Cs_2.5 catalysts was found superior to that of bulk Cs_2.5 owing to the high surface area of the mesoporous supports. While the activity difference between 2D and 3D supports did not meet expectations, mesopore volume had a significant impact on activity, which is attributed to a good access to Cs_2.5H_0.5PW₁₂O₄₀ acid sites. The catalysts could be reused for three times (24 h each time), loosing only 10% glycerol conversion.

Lin Chen;Bendaoud Nohair;东元 赵;Serge Kaliaguine

Applied Catalysis A: General

2018-1-5

A facile ammonia-atmosphere pre-hydrolysis post-synthetic route that can uniformly and selectively deposit Fe ₂O ₃ nanoparticles in the predefined mesopores (5.6 nm) of a bimodal (2.3, 5.6 nm) mesoporous carbon matrix is demonstrated (see figure). The mesoporous magnetic Fe ₂O ₃@C encapsulates show excellent performance for arsenic capture with remarkable adsorption capacity, fast uptake rate, easy magnetic separation, and good cyclic stability.

Zhangxiong Wu;Wei Li;Paul A. Webley;东元 赵

Advanced Materials

2012-1-24

Well-ordered two-dimensional (2D) hexagonal periodic mesoporous organosilicas (PMOs) with a high content of disulfide groups have been prepared by a simple metal-ions-assisted amphiphilic surfactant templating process under a strong acidic condition. Long-chain organic bridge silane, bis(triethoxysilylpropyl)disulfide (BTSPDS) was used as a precursor which can be co-condensed with tetraethoxysilane (TEOS) to assemble with the triblock copolymer Pluronic P123 template and to construct the mesostructured organic-inorganic frameworks. The content of disulfide functional groups is up to 20% (BTSPDS molar content in the initial silane mixture) incorporated into the framework. The obtained ordered mesoporous DS-PMO materials have relatively high BET surface area (∼580 m ² /g), large uniform pore size (up to 6.3 nm) and thick pore walls (thickness up to 7.1 nm), because of the long-chain disulfide bridges. The metal ions such as Zn ²⁺ formed the four-coordination complex with two sulfides of BTSPDS and ethylene oxide moieties of P123 template, which could enhance the interaction between the "soft" long disulfide groups and P123 template, thus improving the mesostructural regularity correspondingly. The disulfide-bridged PMO materials exhibit excellent hydrothermal stability in boiling water for 5 days, probably due to the thick pore walls. SEM images show that after the hydrothermal treatment, the morphology of the ordered disulfide-bridged PMO materials is retained, as that of the wheat-like SBA-15. Excellent adsorption efficiency (∼716 mg/g) for Hg ²⁺ ions is observed, suggesting a potential application in removal of heavy metal ions in wastewater.

Na Hao;Lu Han;Yunxia Yang;Huanting Wang;Paul A. Webley;东元 赵

Applied Surface Science

2010-6-15

A new coordination polymer [Mn₂(NDC)₂(DMF) ₂(H₂O)]_n · nDMF (1) has been synthesized by the reaction of MnCl₂·4H₂O with 2, 6-naphthalenedicarboxylic acids (H₂NDC) under ambient conditions in DMF. A single crystal X-ray diffraction measurement reveals that 1 crystallized in the orthorhombic space group Pbca with a = 1.8334(2) nm, b = 1.6046(17) nm, c = 2.3706(3) nm, V = 6.974(13) nm³, Z = 8, D_c = 1.471 g/cm³, M_r = 772.50, μ = 0.790 mm^-1, F(000) = 3176, S = 0.951, (Δ/σ)_max = 0.001, Δρ _min = 0.539, Δρ_min = -0.351, R = 0.0335, wR = 0.0859. The combination of octahedral manganese (II) ions and NDC ligands leads to the formation of infinite three-dimensional (3D) networks, which have lozenge-shaped 1D channels (0.7 nm × 1.2 nm) along the crystallographic b-axis. The cavities are filled with coordinated solvent molecules (DMF) and non-coordinated ones.

Guo Qiang Zhou;Jin Xi Chen;Zhen Xia Chen;Yun Qi Tian;Ting Yu;Lin Hong Weng;东元 赵

Acta Chimica Sinica

2004

东元 赵;Mietek Jaroniec;Benjamin S. Hsiao

Journal of Materials Chemistry

2010-6-14

Ordered mesoporous TiO ₂ films with high surface area and narrow pore size distribution have been synthesized by using triblock copolymer as the structure - directing agent in nonaqueous media. Electrochemical properties of mesoporous anatase TiO ₂ films have been studied by using cyclic voltammogram and potential step techniques. Large Li ⁺ insertion capacitity was observed by cyclic voltammogram, and the double - layer capacitance has significant effect on cyclic voltammogram curves. The charge transfer coefficient is in the range of 0.15-0.4 for Li ⁺ extraction, and the diffusion coefficient is estimated to be in the range of (4.71-55.8) × 10 ^-12cm ²/s. These results show that the electrochemical properties of Li ⁺ ion insertion of mesoporous anatase TiO ₂ films with high surface area are different from those of normal TiO ₂ films prepared without surfactant.

Zheng Wen Fu;Qian Luo;Wei Zhang;东元 赵;Qi Zong Qin

Acta Chimica Sinica

2000

Uniform core-shell structured magnetic mesoporous TiO₂ (Fe₃O₄@SiO₂@mTiO₂) nanospheres were fabricated via a kinetically controlled Stöber method. A silica interlayer with a thickness of ∼25 nm was introduced as a passivation barrier to prevent photodissociation, as well as increase the thermal stability of the core-shell materials. After crystallizing at 600 °C under nitrogen, the resultant nanospheres (Fe₃O₄@SiO₂@mTiO₂-600) possessed well-defined core-shell structures with a high magnetic susceptibility (∼17.0 emu g^-1) and exhibited uniform mesopores (∼5.2 nm), large BET surface area (∼216 m² g^-1) and large pore volume (∼0.20 cm³ g^-1). More importantly, the magnetic mesoporous TiO₂ was demonstrated for the first time as a highly efficient and stable sonocatalyst for the degradation of bisphenol-A. The pseudo first-order-reaction constant of the magnetic mesoporous TiO₂ was measured to be 0.164 min^-1, which is 1.49 and 2.27 times higher than that of P25 and ultrasound alone, respectively. The remarkable performance is attributed to the fast mass diffusion, large adsorption rate and enhanced hydroxyl-radical-production rate of the nanospheres. More importantly, the catalyst can be easily recycled within 2 minutes using an external magnetic field, and a constant catalytic activity is retained even after eight cycles. This study paves a promising way for the design and synthesis of magnetically separable sonocatalysts for the degradation of organic pollutants, which is of significant importance for practical applications from both environmental and industrial points of view. This journal is

Pengpeng Qiu;Wei Li;Binota Thokchom;Beomguk Park;Mingcan Cui;东元 赵;Jeehyeong Khim

Journal of Materials Chemistry A

2015-3-28