In the present study, a selectively exposed (101)-crystal facet engineered TiO photoanode is investigated for the higher efficiency of the hydrogen evolution reaction. To date, even though the photoelectrochemical performance (PEC) dependent on exposed crystal facets has been calculated and demonstrated in semiconducting microcrystals, selectively exposed crystal facets of photocatalyst thin films have not been reported yet. Herein, we demonstrate a TiO thin film photoanode with 100%-exclusively exposed crystal facets and suggest a methodology to obtain metal oxide thin film photoanodes with selectively exposed crystal facets. A selectively exposed crystal facet-manipulated metal oxide thin film photoanode is fabricated over pre-synthesized microcrystals through a three-step strategy: (1) hydrothermal synthesis of microcrystals, (2) positioning of microcrystals via polymer-induced manual assembly, and (3) fabrication of selectively exposed crystal facets of a TiO thin film through a secondary growth hydrothermal reaction. Based on the synthesis of representative TiO microcrystals with dominantly exposed (101), (100) and (001) crystal facets, the selectively exposed crystal faceted TiO thin film photoanode is comparatively investigated for practical PEC performance. The photocurrent density of the selectively exposed (101) crystal faceted TiO thin film photoanode is determined as 0.13 mA cm and has an 18% conversion efficiency of incident photon-to-current at a 0.65 V Ag/AgCl potential under AM 1.5G illumination. Its photoelectrochemical hydrogen production reached 0.07 mmol cm for 12 h, which is higher than those of (100) and (001) faceted photoelectrodes.

Kim Chang Woo    Yeob So Jin    成会明     Youngsoo Kang   

Energy and Environmental Science

2015

Ever since its discovery, graphene bears great expectations in high frequency electronics due to its irreplaceably high carrier mobility. However, it has long been blamed for the weakness in generating gains, which seriously limits its pace of development. Distributed amplification, on the other hand, has successfully been used in conventional semiconductors to increase the amplifiers' gain-bandwidth product. In this paper, distributed amplification is first applied to graphene. Transmission lines phase-synchronize paralleled graphene field-effect transistors (GFETs), combining the gain of each stage in an additive manner. Simulations were based on fabricated GFETs whose f ranged from 8.5 GHz to 10.5 GHz and f from 12 GHz to 14 GHz. A simulated four-stage graphene distributed amplifier achieved up to 4 dB gain and 3.5 GHz bandwidth, which could be realized with future IC processes. A PCB level graphene distributed amplifier was fabricated as a proof of circuit concept.

Lyu Hongming    Lu Qi    Huang Yilin    Ma Teng    Zhang Jinyu    Wu Xiaoming    Yu Zhiping    任文才    成会明     吴华强    Qian He   

Scientific Reports

2015

The development of semiconductor photocatalysts with highly reactive facets exposed has great potential to improve their photocatalytic reactivity. We report the synthesis of mesoporous rutile TiO single crystals with tunable ratios of {110} and {111} facets through the seeded-template hydrothermal method. With increasing the amount of morphology controlling agent NaF, the facet ratio of {111} to {110} increases, and eventually the mesoporous rutile TiO single crystals with wholly exposed {111} reactive facets are obtained. The resultant faceted mesoporous single crystals exhibit a superior photocatalytic performance of hydrogen evolution to mesoporous single crystals with a large percentage of thermodynamically stable {110} facets, as well as the solid rutile single crystals.

Wu Ting-Ting    Kang Xiangdong    Mohammad Kadi    Ismail Iqbal M.I.    Gang Liu    成会明    

Cuihua Xuebao/Chinese Journal of Catalysis

2015

A film of mesoporous single-crystal rutile TiO rod arrays supported on a transparent conductive glass substrate was synthesized with the assistance of a template layer of closely packed silica nanospheres. This film was used as a photoanode and showed significant improvement for photoelectrochemical water oxidation compared with a reference film of nonporous single-crystal rutile TiO rod arrays.

Zhen Chao    Wu Ting-Ting    Mohammad Kadi    Ismail Iqbal M.I.    Gang Liu    成会明    

Cuihua Xuebao/Chinese Journal of Catalysis

2015

In order to achieve the goals of thermal protection, structure load-bearing and weight reduction of thermal protection materials, a multifunctional integrated composite is fabricated by the combination of slurry infiltration and isothermal chemical vapor infiltration, which has a porous C/C-ZrB-SiC core between two outer layers of compact C/C-ZrB-SiC and C/C-SiC. Compared to a C/SiC composite with a density of 2.1gcm, the material presents a low density of 1.65gcm and a 65% lower thermal conductivity in-thickness (3.29WmK), while its flexural strength is 260MPa, only 16% lower. In addition, the integrated composite exhibits a good ablation resistance with a linear ablation rate of 0.79μm/s for 1000s.

Hu Chenglong    Pang Shengyang    Tang Sufang    Wang Yongcai    成会明    

Journal of the European Ceramic Society

2015

Liang Ji    Li Feng    成会明    

Energy Storage Materials

2015

Electronic conduction along the [001] direction of a faceted anatase TiO particle in contact with two tungsten probes is found to be an order of magnitude higher than that along the [010] direction due to a smaller potential barrier of the TiO(001)-tungsten interface for electron transport than the TiO(010)-tungsten interface. This finding could guide the design of TiO-based electrodes.

刘刚    Lichang Yin    Jian Pan    Li Feng    Wen Lei    Zhen Chao    成会明    

Advanced Materials

2015

With the advent of flexible electronics, flexible lithium-ion batteries (LIBs) have attracted great attention as a promising power source in the emerging field of flexible and wearable electronic devices. Flexible electrode materials are core components for constructing flexible LIBs. Graphene has many outstanding properties, such as high surface area, excellent electrical conductivity, good mechanical and chemical properties. Therefore, graphene has great potential applications in flexible LIBs. According to the degree of elastic deformation, flexible LIBs can be divided into bendable and stretchable LIBs. In this chapter, we begin with a brief definition of flexible LIBs and the innovative design of stretchable LIBs for applications in this field. This is followed by a detailed overview of the recent progress on bendable electrode materials design based on graphene. Graphene can act as a kind of conductive phase to form composite films with polymer, paper, and cloth. Also graphene can act as bendable current collectors or graphene-based bendable composite materials in bendable batteries, and graphene fiber-based electrodes can also act as a component to construct bendable LIBs. Graphene-based bendable electrode can effectively improve flexibility, power density, and energy density of LIBs, and it is much anticipated in the future. Furthermore, we show characterization of flexible LIBs, including mechanical properties and electrochemical performance. At last, we look forward to the future development in flexible LIBs and believe the great challenge confronting the scientific researchers is to design a flexible batteries with stretchability, self-healing ability, and high charge rates.

温磊    Li Feng    Luo    成会明    

Nanocarbons for Advanced Energy Storage

2015

Double-wall carbon nanotubes (DWCNTs) with a uniform diameter and high thermal stability were synthesized by a floating catalyst chemical vapor deposition method using sulfur as the growth promoter and CH as the carbon source under a hydrogen atmosphere. The DWCNTs obtained have a mean diameter of ∼3 nm and a high oxidation resistance temperature of 785 °C. Transparent conductive films (TCFs) based on the DWCNTs produced by a simple filtration method showed excellent optoelectronic performance of 83 Ω sq with 79% transmittance at 550 nm, which is the best performance ever reported for pristine CNT TCFs. These desirable properties are ascribed to the moderate diameter, long length and structural integrity of the DWCNTs that are responsible for the films' good electrical conductivity and high transmittance. © 2014 The Royal Society of Chemistry.

Pengxiang Hou    Yu Bing    Su Yang    Shi Chao    Lili li Zhang    Chang Liu    Shisheng Li    Jinhong Du    成会明    

Journal of Materials Chemistry A

2014

We fabricated a monolithic FeO/graphene hybrid directly by hydrothermal reaction of ferrous oxalate dihydrate and graphene oxide without using a reducing agent. The reduced graphene oxide formed an interconnected network structure that can be used as a support for homogeneous distribution of active FeO nanoparticles. The graphene network and the pore channels in the hybrid facilitate fast electron transfer and ion transport. This hybrid can be directly used as a free-standing anode for lithium ion batteries, which simplifies the fabrication procedure of electrodes, and also exhibited a high capacity of 1062 mA h g at 100 mA g, high rate capability and excellent cyclic stability over 100 cycles. Furthermore, as a self-supported adsorbent, it provides a new idea on loading active materials to the suitable substrate, which can be used as a promising material for water purification due to its easy collection and excellent capability in removing As(V) from water. The results demonstrate the promising applications of bulk reduced assembly of graphene with functional metal oxides, which will be helpful for future development of graphene-based multifunctional materials. © 2013 Elsevier Ltd. All rights reserved.

Lü Li    Guangmin Zhou    Zhe Weng    Shan Xuyi    Feng Li    成会明    

Carbon

2014