Mesoporous thin films with various compositions are unique architectures for photoelectrochemical (PEC) solar cells. In this paper, we report the synthesis of highly ordered, multi-layered, continuous mesoporous TiO thin films with uniform large pores, crystalline walls and tunable film thickness, via a ligand-assisted evaporation induced self assembly (EISA) method. A Ti(acetylacetone) precursor and a diblock copolymer PEO-b-PS are employed for the controlled assembly of the TiO/template mesostructure, followed by a two-step pyrolysis that generates carbon residue as an intermediate protection layer to support the TiO framework and mesostructures during the crystallization. Other transition metal ion dopants (such as Cr, Ni and Co) can be facilely incorporated into the TiO frameworks by co-assembly of these metal acetylacetone precursors during the EISA process. The obtained TiO thin film possesses an ordered monoclinic mesostructure distorted from a (110)-oriented primitive cubic structure, uniform and tunable large pores of 10-30 nm, a large surface area of ∼100 m g and a high crystallinity anatase wall. The film thickness can be well controlled from 150 nm to several microns to tune the absorption, with the capability of generating free-standing film morphologies. Furthermore, this designed architecture allows for effective post-deposition of other small-bandgap semiconductor nanomaterials inside the large, open and interconnecting mesopores, leading to significantly improved solar absorption and photoconversion. As a proof-of-concept, we demonstrate that the photoanodes made of 4.75 μm thick mesoporous TiO film with deposited cadmium sulfide quantum dots exhibit excellent performance in PEC water splitting, with an optimized photocurrent density of 6.03 mA cm and a photoconversion efficiency of 3.9%. These multi-layered mesoporous TiO-based thin films can serve as a unique architecture for PEC and other solar energy conversion and utilization. © 2013 The Royal Society of Chemistry.

Dan Feng    Luo Wei    Junyong Zhang    Ming Xu    张任远    Haoyu Wu    Yingying Lv    Abdullah Asiri    Sher bahadar Khan    Rahman Mohammed M.    郑耿峰    赵东元    

Journal of Materials Chemistry A

2013

Well core-shell composites of USY@Mesosilica with the mesoporous silica shell and little dealuminated USY zeolite core were synthesized by separating two processes of assembly and crystallization in the distinct conditions. The mesoporous silica of shell has the wormhole-like structure with large pore size and thick pore wall, as SBA-15 silica. No phase separation of mesoporous silica and USY zeolite was observed in the composites. The mesoporous shell thickness was controlled from 20 nm to 60 nm by adjusting the ratio of TEOS/USY from 1.26 to 2.52. The aluminium introduced composites of USY@Al-Mesosilica displayed excellent selectivity of liquid products of C-C in cracking n-hexadecane at high conversion. The ratios of Liquid to Gas in the products were 0.99, 1.12 and 1.88 at the conversion of 94.83%, 86.21% and 76.64%, corresponding to the composites with the shell thickness of 20, 40 and 60 nm, respectively. The ratios are much higher than that of pure USY zeolite (0.45) and the mechanical mixture of USY and AlSBA-15 (0.54). In hydrocracking Iran VGO-2 heavy oil, the NiW supported catalyst prepared from the core-shell composite of USY@Al-Mesosilica displayed excellent catalytic performances with higher activity and better selectivity than the catalyst prepared from pure USY zeolite. The core-shell composites present a potential application in hydrotreating of heavy oil. © 2013 Elsevier Inc.All rights reserved.

Jia Lixia    Sun Xiaoyan    Ye Xiuqun    Zou Chenglong    Gu Haifang    黄曜    牛国兴    赵东元    

Microporous and Mesoporous Materials

2013

Two types of LiMn2O4 microspheres with similar sizes but adjustable hollow structures have been synthesized using a new and simple approach. Their performance as cathode materials for lithium ion battery applications has been studied and correlated with the hollow structural parameters. Through a solid state reaction between LiOH and mesoporous MnO 2 obtained by the complete decomposition of MnCO3, LiMn2O4 hollow spheres with a robust wall and small cavity size are prepared (LiMn2O4-A). The fusion of the mesopores and the Kirkendall effect during the lithiation process are responsible for the hollow interior formation. In another approach through partial decomposition and selective etching, LiMn2O4 hollow spheres with thin walls are prepared (LiMn2O4-B). It is demonstrated that LiMn2O4-A shows larger capacity, superior rate capability, and better cycling stability compared to LiMn 2O4-B. The former exhibits an initial discharge capacity of ∼120 mA h g^-1, maintains 96.6% of the initial capacity after 105 cycles at 1 C and ∼90% of the capacity at 0.1 C when discharged at 5 C. © 2013 The Royal Society of Chemistry.

Liang Zhou    Xufeng Zhou    Xiaodan Huang    Zhaoping Liu    赵东元     姚向东    Chengzhong Yu   

Journal of Materials Chemistry A

2013

A controllable one-pot method to synthesize N-doped ordered mesoporous carbons (NMC) with a high N content by using dicyandiamide as a nitrogen source via an evaporation-induced self-assembly process is reported. In this synthesis, resol molecules can bridge the Pluronic F127 template and dicyandiamide via hydrogen bonding and electrostatic interactions. During thermosetting at 100 °C for formation of rigid phenolic resin and subsequent pyrolysis at 600 °C for carbonization, dicyandiamide provides closed N species while resol can form a stable framework, thus ensuring the successful synthesis of ordered N-doped mesoporous carbon. The obtained N-doped ordered mesoporous carbons possess tunable mesostructures (p6m and Im3̄m symmetry) and pore size (3.1-17.6 nm), high surface area (494-586 m g), and high N content (up to 13.1 wt%). Ascribed to the unique feature of large surface area and high N contents, NMC materials show high CO capture of 2.8-3.2 mmol g at 298 K and 1.0 bar, and exhibit good performance as the supercapacitor electrode with specific capacitances of 262 F g (in 1 M HSO) and 227 F g (in 6 M KOH) at a current density of 0.2 A g. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Jing Wei    Dandan Zhou    Zhenkun Sun    邓勇辉    夏永姚    赵东元    

Advanced Functional Materials

2013

In this work, porous Co3O4 materials were prepared via a solid-state conversion process of a freshly prepared cobalt-based metal-organic framework (Co-MOF) crystal. Herein, the unique Co-MOF crystal was formed via the specific chemical coordination between the carboxylic ligand azobenzene-3,5,4′-tricarboxylic acid (H3ABTC) and the auxiliary ligand 4,4′-bipyridine (bpy) to construct 2-dimensional (2D) bilayer structural intermediates, which subsequently formed a 3D polycatenation supramolecular array architecture with the assistance of π-π stacking and hydrogen bonding interactions. Subsequently, porous Co3O4 particles were obtained by simple thermolysis of the Co-MOF crystals via a two-step calcination treatment. The results demonstrated that the as-made Co3O4 displays crystalline and well-defined porous features and can be applied as a supercapacitor electrode, and its energy storage performances were investigated in 2 M KOH electrolyte. The electrochemical results showed that the porous Co3O4 particles exhibit a high specific capacitance of 150 F g^-1 at a current density of 1 A g^-1 and retain slightly enhanced capacitance after 3400 cycles, which could be ascribed to its higher specific surface area and accessible channel structural features. The present approach is facile, controllable, and reproducible. Importantly, this specific solid-state thermal conversion strategy could be easily extended to prepare other porous metal and/or metal oxide nanomaterials with specific surface textures and morphologies. © The Royal Society of Chemistry 2013.

Fanli Meng    Fang Zhiguo    Zuoxi Li    Xu Weiwei    Wang Mengjiao    Liu Yanping    Ji Zhang    Wang Wanren    赵东元     Xiaohui Guo   

Journal of Materials Chemistry A

2013

The synthesis of supported bimetal oxide nanoparticles for catalytic applications has greatly suffered from the strong phase separation trend and particle aggregation problem. We found that just adding facile pre-drying treatment before the calcination step can sufficiently avoid the phase separation and prevent the particles from aggregation. Well dispersed pure phase CuFeO supported on a mesoporous silica catalyst was thus synthesized by using copper and iron nitrates as the precursors and KIT-6 as the support. It was used as the catalyst for the asymmetric hydrosilylation of aryl ketone. The reaction yield and ee value can both reach 93%. The synthesized CuFeO possesses superparamagnetic properties, which ensures it can be easily recycled by an external magnetic field for reuse. This synthesis strategy can also be applied to various bimetal oxides, including NiFeO, CuCrO, CoFeO, etc. © 2013 The Royal Society of Chemistry.

Bin Li    Li Min    Yao Chaohua    施益峰    Ye Danru    Jing Wu    赵东元    

Journal of Materials Chemistry A

2013

3D porous hierarchical CuS microsponges (HCMs) constructed from 2D ultrathin active nanosheets (∼1.5 nm) with nearly 99% exposed (111) facets are fabricated by a simple hydrothermal route. The as-prepared HCMs possess an improved visible-light-harvesting ability, high surface area, low electron-hole recombination, and excellent photocatalytic activity for phenol degradation under visible light irradiation. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

刘勇    邓勇辉    Zhenkun Sun    Jing Wei    郑耿峰    Abdullah Asiri    Sher bahadar Khan    Rahman Mohammed M.    赵东元    

Small

2013

The combination of nanotechnology and biology has developed into an emerging research area: nano-biotechnology. Upconversion nanoparticles (UCNPs) have attracted a great deal of attention in bioapplications due to their high chemical stability, low toxicity, and high signal-to-noise ratio. Magnetic nanoparticles (MNPs) are also well-established nanomaterials that offer controlled size, ability to be manipulated externally, and enhancement of contrast in magnetic resonance imaging (MRI). As a result, these nanoparticles could have many applications in biology and medicine, including protein purification, drug delivery, and medical imaging. Because of the potential benefits of multimodal functionality in biomedical applications, researchers would like to design and fabricate multifunctional upconversion-magnetic hybrid nanostructured materials. The hybrid nanostructures, which combine UCNPs with MNPs, exhibit upconversion fluorescence alongside super-paramagnetism property. Such structures could provide a platform for enhanced bioimaging and controlled drug delivery. We expect that the combination of unique structural characteristics and integrated functions of multifunctional upconversion-magnetic nanoparticles will attract increasing research interest and could lead to new opportunities in nano-bioapplications. © Ivyspring International Publisher.

Xiaomin Li    赵东元     张凡   

Theranostics

2013

Ready to load: A shear stress regulated assembly route has been used to fabricate silica nanotubes and hollow mesostructures thereof. The packed silica nanotubes were employed as support for loading gold nanoparticles for efficiently catalyzing the epoxidation of styrene with high conversion and selectivity towards styrene oxide. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chun Wang    Jing Wei    Qin Yue    Luo Wei    Yuhui Li    Minghong Wang    邓勇辉    赵东元    

Angewandte Chemie - International Edition

2013

Fanli Meng    Fang Zhiguo    Zuoxi Li    Xu Weiwei    Wang Mengjiao    Liu Yanping    Zhang Ji    Wang Wanren    赵东元     Xiaohui Guo   

Journal of Materials Chemistry A

2013