A general solvent-free assembly approach via directly heating amino acid and mesoporous silica mixtures is developed for the synthesis of a family of highly nitrogen-doped mesoporous carbons. Amino acids have been used as the sole precursors for templating synthesis of a series of ordered mesoporous carbons. During heating, amino acids are melted and strongly interact with silica, leading to effective loading and improved carbon yields (up to ≈25 wt%), thus to successful structure replication and nitrogen-doping. Unique solvent-free structure assembly mechanisms are proposed and elucidated semi-quantitatively by using two affinity scales. Significantly high nitrogen-doping levels are achieved, up to 9.4 (16.0) wt% via carbonization at 900 (700) °C. The diverse types of amino acids, their variable interactions with silica and different pyrolytic behaviors lead to nitrogen-doped mesoporous carbons with tunable surface areas (700–1400 m g), pore volumes (0.9–2.5 cm g), pore sizes (4.3–10 nm), and particle sizes from a single template. As demonstrations, the typical nitrogen-doped carbons show good performance in CO capture with high CO/N selectivities up to ≈48. Moreover, they show attractive performance for oxygen reduction reaction, with an onset and a half-wave potential of ≈−0.06 and −0.14 V (vs Ag/AgCl).

Gao Xingmin    Chen Zhi    Yao Yan    Zhou Mengyuan    刘勇    Jinxiu Wang    Wu Winston Duo    陈晓东    吴张雄    赵东元    

Advanced Functional Materials

2016

Fang Yin    Yingying Lv    Gong Feng    Ahmed Elzatahry    郑耿峰    赵东元    

Advanced Materials

2016

Exploring facile and reproducible methods to prepare mesoporous TiO nanospheres is crucial for improving the performance of TiO materials for energy conversion and storage. Herein, we report a simple and reproducible double-surfactant assembly-directed method to prepare monodisperse mesoporous TiO nanospheres. A double-surfactant system of n-dodecylamine (DDA) and Pluronic F127 was adopted to control the hydrolysis and condensation rates of tetrabutyl titanate in a mixture of water and alcohol at room temperature. In this process, the diameter size of mesoporous TiO nanospheres can be simply tuned from ∼50 to 250 nm by varying the concentration of HO and surfactants. The double-surfactant system of DDA and F127 plays an effective role in determining the size, morphology, and monodispersity of mesoporous TiO nanospheres to reduce agglomeration during the sol-gel process. The resultant mesoporous anatase TiO nanospheres after solvothermal treatment at 160 °C are built of interpenetrating nanocrystals with a size of ∼10 nm, which are arranged to obtain a large number of connecting mesopores. Mesoporous TiO nanospheres with a small diameter size of around 50 nm possess a high surface area (∼160 m/g) and mesopores with sizes of 4-30 nm. The small diameter size, high crystallinity, and mesoporous structure of TiO nanospheres lead to excellent performance in cycling stability and rate capability for lithium-ion batteries. After 500 cycles, the monodisperse mesoporous TiO nanospheres exhibit a charge capacity as high as 156 mAhg without obvious fade, and the Coulombic efficiency can reach up to 100%.

Zhu Hongwei    Shang Yesheng    Jing Yunke    Liu Yang    Yupu Liu    El-Toni Ahmed Mohamed    张凡    赵东元    

ACS Applied Materials and Interfaces

2016

Wang Faxing    Wang Chun    Yujuan Zhao    Liu Zaichun    Zheng Chang    Fu Lijun    Yusong Zhu    吴宇平    赵东元    

Small

2016

A gradient pyrolysis approach has been adopted for synthesis of ordered mesoporous carbonaceous materials with different surface and textural properties for removal of hexachlorobenzene. The resultant ordered mesoporous carbonaceous materials possess high surface areas (364-888 m/g), large pore volumes (0.23-0.47 cm/g), uniform pore sizes (2.6-3.8 nm), and tunable hydrophobic properties. They show high-efficiency removal performances for hexachlorobenzene with high adsorption capacity of 594.2-992.1 μg/g. An enhanced removal rate (>99%) can be obtained with the increasing pyrolysis temperature (900 °C) as a result of the strong hydrophobic-hydrophobic interaction between the carbon framework and hexachlorobenzene molecules. Furthermore, the adsorption behaviors follow the Sips isotherm model and obey the pseudo-first-order kinetic model.

范建伟    Xianqiang Ran    Yuan Ren    Chun Wang    杨建平    Wei Teng    Zou Liyin    Sun Yu    Lu Bin    邓勇辉    赵东元    

Langmuir

2016

赵东元     Hiroshi Imahori    Schmidt Christine    Peter Skabara    McKenzie Fiona    Kelti Sam   

Journal of Materials Chemistry C

2015

赵东元     Hiroshi Imahori    Schmidt Christine    Peter Skabara    McKenzie Fiona    Keltie Sam   

Journal of Materials Chemistry A

2015

Highly branched TiO interpenetrating network architectures decorated with SnO nanocrystals were fabricated through a sacrificial-template approach for selective catalytic reduction of NO with ammonia. Such unique architectures demonstrate outstanding catalytic activity for NO conversion (∼90%), high N selectivity (∼100%), good stability and strong resistance to SO and HO poisoning over a broad temperature range (75-325 °C). This journal is

Chen Minjun    杨建平    刘勇    李炜    范建伟    Xianqiang Ran    Wei Teng    Sun Yu    张伟贤    李光明    窦士学    赵东元    

Journal of Materials Chemistry A

2015

Yue Qin    Yu Zhang    Wang Can    Xiqing Wang    Zhenkun Sun    Hou Xiu-Feng    赵东元     邓勇辉   

Journal of Materials Chemistry A

2015

Uniform oxide deposition on graphene to form a sandwich-like configuration is a well-known challenge mainly due to their large lattice mismatches and poor affinities. Herein, we report a general strategy to synthesize uniform mesoporous TiO/graphene/mesoporous TiO sandwich-like nanosheets (denoted as G@mTiO), which cannot be achieved by conventional one-pot synthetic methods. We show that by rational control of hydrolysis and condensation of Ti precursors in a slow way, GO sheets can be conformably coated by amorphous TiO shells, which then can be facilely transformed into the well-defined G@mTiO nanosheets by annealing. This amorphous-to-crystalline strategy conveniently allows bypassing strain fields that would inevitably arise if direct growth of mesoporous anatase shells on graphene. As distinct from the most common structures of graphene-based composites (mixed, wrapped, or anchored models), the resultant materials display a uniform sandwich-like configuration: few-layer graphene conformably encapsulated by mesoporous TiO shells. This new G@mTiO nanosheet exhibits ultrathin nature (∼34 nm), small size and high crystalline nanocrystals (∼6 nm), high surface areas (∼252 m/g) and uniform mesopores (∼3.4 nm). We further show that the thickness of mesoporous TiO shells can be facilely adjusted as desired by controlling the ammonia content, and this facile strategy can be easily extended to design other oxide/graphene/oxide sandwich-like materials. More importantly, we showcase the benefits of the resultant G@mTiO nanosheets as anodes in lithium ion batteries: they deliver an extra high capacity, an excellent high-rate capability, and long cycle life.

李炜    Fei Wang    Yupu Liu    Jinxiu Wang    杨建平    Zhang Lijuan    Ahmed Elzatahry    Al-Dahyan Daifallah    夏永姚    赵东元    

Nano Letters

2015