In this article, an ordered two-dimensional (2D) hexagonal mesoporous anatase crystals–silica nanocomposite was first synthesized using synchronous-assembly of surfactant and inorganic precursors molecules, and then a three-dimensional (3D) interconnected mesoporous anatase TiO was prepared via an “extracting silica” approach. The results show that the mesopore channels in our titania are highly connected by plenty of 3D uniform intrawall mesopores while retaining mesostructural integrity and regularity. The TiO prepared is completely anatase crystalline with uniform nanocrystals (13.0 nm in size) and a high specific surface area (∼ 145 m/g). This method is mild, simple and can be easily repeatable. The photocatalytic degradation rates of Acid Red 1 (0.173 min) and microcystin−LR (2.57 min) on the interconnected mesoporous TiO are very high, which are 41.6 and 2.85 times higher than that of the parent sample; 29.2 and 7.20 times that of P25 photocatalyst, respectively. These results clearly demonstrated that the 3D interconnected mesostructure played a key role in the activity increments. In addition, our photocatalysts are considerably stable and reusable. To the best of our knowledge, such results have not been seen in the literature before. Furthermore, the fundamentals of this study would provide new insights for the rational design and preparation of 3D highly interlinked mesoporous metal-oxides with unique photocatalytic performances.

董维阳    Yao Youwei    Li Li    Yaojun Sun    华伟明    庄国顺    赵东元     Shuwen Yan    宋卫华   

Applied Catalysis B: Environmental

2017

Photon management has enabled a true revolution in the development of high-performance semiconductor materials and devices. Harnessing the highest amount of energy from photons relies on the ability to design and fashion structures to trap the light for a longer time inside the device for more electron excitation. The light harvesting efficiency in many thin-film optoelectronic devices is limited due to low photon absorbance. Here we demonstrate for the first time that slow photon circulation in sandwich-structured photonic crystals with two stopbands fine tuned is ideally suited to enhance and spectrally engineer light absorption. The sandwich-structured TiO inverse opal possesses two stopbands, whose blue or red edge is respectively tuned to overlap with the electronic excitation energy of TiO, thereby circulating the slow photons in the middle layer and enhancing light scattering at layer interfaces. This concept, together with the significantly increased control over photon management opens up tremendous opportunities for the realization of a wide range of high-performance, optoelectronic devices, and photochemical reactions.

Eftekhari Ehsan    Broisson Pierre    Aravindakshan Nikhil    Wu Zhiqing    Ivan Cole    Xiaomin Li    赵东元     Qin Li   

Journal of Materials Chemistry A

2017

Hollow TiO porous microspheres consisted of numerous well-crystalline nanocrystals with superior structural integrity and robust hollow interior were synthesized by a facile sol-gel template-assisted approach and two-step carbonprotected calcination method, together with hydrogenation treatment. They exhibit a uniform diameter of ~470 nm with a thin porous wall shell of ~50 nm in thickness. The Brunauer-Emmett-Teller (BET) surface area and pore volume are ~19 m/g and 0.07 cm/g, respectively. These hollow TiO porous microspheres demonstrated excellent lithium storage performance with stable capacity retention for over 300 cycles (a high capacity of 151 mAh/g can be obtained up to 300 cycles at 1 C, retaining 81.6% of the initial capacity of 185 mAh/g) and enhanced rate capability even up to 10 C (222, 192, 121, and 92.1 mAh/g at current rates of 0.5, 1, 5, and 10 C, respectively). The intrinsic increased conductivity of the hydrogenated TiO microspheres and their robust hollow structure beneficial for lithium ion-electron diffusion and mitigating the structural strain synergistically contribute to the remarkable improvements in their cycling stability and rate performance.

Chun Wang    Wang Faxing    Yujuan Zhao    Yuhui Li    Yue Qin    Yupu Liu    刘勇    Ahmed Elzatahry    Abdullah Al-Enizi    Wu Yuping    邓勇辉    赵东元    

Nano Research

2016

Ultrahigh surface area single-crystals of periodic mesoporous organosilica (PMOs) with uniform cubic or truncated-cubic morphology and organic/inorganic components homogeneously distributed over the whole frameworks have successfully been prepared by a sol-gel surfactantlating method. By tuning the porous feature and polymerization degree, the surface areas of the obtained PMO nanocubes can reach as high as 2370 m/g, which is the highest for silica-based mesoporous materials. The ultrahigh surface area of the obtained PMO single crystals is mainly resulted from abundant micropores in the mesoporous frameworks. Furthermore, the diameter of the nanocubes can also be well controlled from 150 to 600 nm. The materials show ultrahigh CO adsorption capacity (up to 1.42 mmol/g at 273 K) which is much higher than other porous silica materials and comparable to some carbonaceous materials. The adsorption of CO into the PMO nanocubes is mainly in physical interaction, therefore the adsorption-desorption process is highly reversible and the adsorption capacity is much dependent on the surface area of the materials. Moreover, the selectivity is also very high (∼11 times to N) towards CO adsorption.

Yong Wei    Xiaomin Li    Zhang Renyuan    刘勇    Wang Wenxing    Ling Yun    El-Toni Ahmed Mohamed    赵东元    

Scientific Reports

2016

Well ordered, uniform 3D open macro/mesoporous TiO hollow microspheres with highly crystalline anatase thin shells have been successfully synthesized by a simple solvent evaporation-driven confined self-assembly method. The 3D open macro/mesoporous TiO hollow microspheres show high energy-conversion efficiency (up to 9.5%) and remarkable photocatalytic activity (with photodegradation of 100% for methylene blue in 12 min under UV light irradiation).

刘勇    Lan Kun    Bagabas Abdulaziz    Zhang Pengfei    Gao Wenjun    Wang Jingxiu    Sun Zhenkun    Fan Jianwei    Ahmed Elzatahry    赵东元    

Small

2016

The electrochemical performance of nanocomposites could greatly be improved by rationally designing flexible core-shell heterostructures. Typically, the uniform coating of a thin mesoporous crystalline transition metal oxide shell on flexible graphitized carbon supports can provide both fast ion and electron transport pathways, which is an ideal material for high-performance lithium-ion batteries. Herein, we report a surfactant-templating assembly coating method to deposit an ultrathin mesoporous crystalline TiO shell on flexible graphitized carbon supports by using amphiphilic triblock copolymer Pluronic F127 as a template. Taking multi-wall carbon nanotubes (CNTs) as an example support, the obtained flexible CNTs@mTiO hybrid mesoporous nanocables exhibit an ultra-high surface area (~137 m/g), large internal pore volume (~0.26 cm/g), uniform accessible mesopores (~6.2 nm) and ultrathin highly-crystalline mesoporous anatase shells (~20 nm in thickness). As an anode material for lithium battery, the flexible CNTs@mTiO hybrid mesoporous nanocables show high-rate capacity (~210 mA h g at 20 C, 1 C=170 mA g), high Coulombic efficiency (nearly 100% during 1000 cycles at 20 C) and ultralong-cycling life (keeping ~210 mAh g after 1000 cycles at 20 C). The strong synergistic coupling effect between CNT cores and thin mesoporous TiO shells, high surface area, accessible large pores and highly crystalline thin mesoporous shells result in excellent performance in lithium batteries. This versatile surfactant-templating assembly coating method can be easily extended to deposit an ultrathin mesoporous TiO layer on flat graphene (GR) to form a uniform sandwich-like flexible GR@mTiO nanoflakes, which opens up a new opportunity for depositing thin mesoporous transition-metal oxides on graphitized carbon supports for advanced applications in energy conversion and storage, photocatalysis, sensors and drug delivery, etc.

刘勇    Ahmed Elzatahry    Wei Luo    Lan Kun    Zhang Pengfei    范建伟    Yong Wei    Chun Wang    邓勇辉    郑耿峰    张凡    Tang Yun    Liqiang Mai    赵东元    

Nano Energy

2016

Hydrogenated black TiO has been proven to tune the bandgap and utilize solar energy effectively. Herein, we report a facile strategy for controllably synthesizing stable mesoporous black TiO hollow spheres (MBTHSs) with a narrow bandgap via a template-free solvothermal approach combined with a small amine molecule reflux-encircling process and subsequent high-temperature hydrogenation, which are composed of highly crystalline pore-walls, Ti in frameworks and surface disorders. The encircled protectors especially ethylenediamine result in high thermostability of the TiO hollow structures, which not only facilitate hydrogenation (600 °C), but also inhibit grain growth and anatase-to-rutile phase transformation as well as retain a high structural integrity. The MBTHSs with a diameter of ∼700 nm possess a relatively high surface area of ∼80 m g, large pore size and pore volume of ∼12 nm and ∼0.20 cm g, respectively. The diameters and wall thicknesses are controllable from ∼500 nm to 1 μm and ∼35 to 115 nm, respectively. The high crystallinity, integrated hollow structure, Ti in frameworks and surface disorders of the MBTHSs give rise to an extending photoresponse from the ultraviolet to the visible light region and significant improvement in the solar-driven photocatalytic hydrogen evolution rate (241 μmol h 0.1 g), which is two times as high as that of black TiO nanoparticles (118 μmol h 0.1 g) and almost three times that of pristine mesoporous TiO hollow spheres (81 μmol h 0.1 g), respectively.

Hu Weiyao    Wei Zhou    Zhang Kaifu    Zhang Xiangcheng    Lei Wang    Baojiang Jiang    Guohui Tian    赵东元     Fu Honggang   

Journal of Materials Chemistry A

2016

Indoor organic gaseous pollution is a global health problem, which seriously threats the health and life of human all over the world. Hence, it is important to fabricate new sensing materials with high sensitivity and efficiency for indoor volatile organic compounds. In this study, a series of ordered mesoporous silica-based nanocomposites with uniform carbon coatings on the internal surface of silica mesopore channels were synthesized through a simple template-carbonization strategy. The obtained mesoporous silica-carbon nanocomposites not only possess ordered mesostructures, high surface areas (up to ~759 m g), large and tunable pore sizes (2.6-10.2 nm), but also have the improved hydrophobicity and anti-interference capability to environmental humidity. The sensing performances of the mesoporous silica-carbon nanocomposites to volatile organic compounds, such as ethylbenzene, methylbenzene, benzene, methanol, acetone, formaldehyde, dichloromethane and tetrahydrofuran, were systematically investigated. The relationships between the sensing performances and their properties, including mesostructures, surface areas, pore sizes, carbon contents and surface hydrophilic/hydrophobic interactions, have been achieved. The mesoporous silica-carbon nanocomposites with hexagonal mesostructure exhibit outstanding performance at room temperature to benzene and acetone with high responses, short response (2-3 s) and recovery (16-19 s) time, strong anti-interference to environmental humidity, and long-term stability (less than ~5% loss of the frequency shifts after 42 days). Therefore, the obtained mesoporous silica-carbon nanocomposites have a hopeful prospect in the field of environmental air quality monitoring.

Yupu Liu    Junchen Chen    李炜    Dengke Shen    Yujuan Zhao    Manas Pal    Yu Haijun    屠波    赵东元    

Journal of Colloid and Interface Science

2016

A seeded watermelon-like mesoporous nanostructure (mSiO@CdTe@SiO, mSQS) composed of a novel dendritic mesoporous silica core, fluorescent CdTe quantum dots (QDs), and a protective solid silica shell is successfully fabricated by loading QDs into dendritic mesoporous silica nanoparticles through electrostatic interaction, and then coating with a solid silica shell by the modified Stöber method. The shell thickness of mSQS can be tuned from 0 to 32 nm as desired by controlling the reaction parameters, including the amount of silica precursor, tetraethyl orthosilicate, that is introduced, the solvent ratio (HO:ethanol), and the amount of catalyst (NHHO). These fluorescent mSiO@QDs@SiO nanoparticles possess excellent stability and thickness-dependent cytotoxicity, and are successfully applied to bioimaging. A seeded watermelon-like fluorescent mesoporous nanostructure (mSiO@CdTe@SiO) composed of a novel dendritic mesoporous silica core, fluorescent CdTe quantum dots, and a protective solid silica shell is successfully fabricated and applied to in vitro and in vivo bioimaging.

Shaohua Zhang    Wen Ling    Jianping Yang    Zeng Jianfeng    Sun Qiao    Zhen Li    赵东元     窦士学   

Particle and Particle Systems Characterization

2016

The surface engineering on various functional nanomaterials has enabled the creation of diverse nanocomposites that possess pre-designed architectures with improved and complementary properties. Magnetic porous materials with core-shell structures have recently received great attentions due to the combination of the respective properties of cores and shells that achieves cooperatively boosted performance. Core-shell magnetic nanoparticles are well-known for their outstanding properties of enhanced stability, being able to protect the active species from harsh environments, improved physical, chemical and photoelectric properties, and easiness of surface functionalization, etc. All of their exciting synergistic properties are heavily depending on the controllable and ingenious design towards cores and shells, and precise regulation of the interaction between them. In this paper, different surface engineering strategies, based on sol-gel chemistry and confined interfacial coating, for the construction of iron oxide-mesoporous core-shell materials have been reviewed. Attentions are paid not only on the selection of promising candidates for cores or porous shells and the creation of different shapes, but also more importantly on the synthetic principles and mechanisms for interfacial control in achieving perfectly adjustment of porous shells with various compositions, different pore sizes, pore structures and functionalities. Following the methods and principles presented in the review, it is very easy even for new beginners to synthesize various magnetic porous materials with well-defined core-shell structure and integrated functionalities for various applications.

Zhenkun Sun    Zhou Xinran    Wei Luo    Qin Yue    Yu Zhang    程晓维    李炜    孔彪    邓勇辉    赵东元    

Nano Today

2016