General Characterization Methods for Photoelectrochemical Cells for Solar Water Splitting.

Shi, Xinjian,Cai, Lili,Ma, Ming,Zheng, Xiaolin,Park, Jong Hyeok Wiley-VCH 2015 ChemSusChem Vol.8 No.19

<P>Photoelectrochemical (PEC) water splitting is a very promising technology that converts water into clean hydrogen fuel and oxygen by using solar light. However, the characterization methods for PEC cells are diverse and a systematic introduction to characterization methods for PEC cells has rarely been attempted. Unlike most other review articles that focus mainly on the material used for the working electrodes of PEC cells, this review introduces general characterization methods for PEC cells, including their basic configurations and methods for characterizing their performance under various conditions, regardless of the materials used. Detailed experimental operation procedures with theoretical information are provided for each characterization method. The PEC research area is rapidly expanding and more researchers are beginning to devote themselves to related work. Therefore, the content of this Minireview can provide entry-level knowledge to beginners in the area of PEC, which might accelerate progress in this area.</P>

Chemical Compositions and Volatile Compounds of Tricholoma matsutake from Different Geographical Areas at Different Stages of Maturity

Qiang Li,Li Zhang,Wanhua Li,Xiaolin Li,Wenli Huang,Hua Yang,Linyong Zheng 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.1

Tricholoma matsutake is a commercially important edible fungus. Volatile compounds, chemical compositions, and nutritional values of fruiting bodies at different stages of maturity from different geographical areas were analyzed. The main volatile compounds in T. matsutake fruiting bodies were (E)-2-octenal, phenylacetaldehyde, 3-octanone, methyl cinnamate, benzaldehyde, and 1- octen-3-ol. Kinds and levels of volatile compounds from different geographical areas varied. As the fruiting bodies aged, levels of methyl cinnamate and 1-octen-3-ol gradually declined. Potassium was the most abundant element in T. matsutake fruiting bodies. Of 17 amino acids detected in fruiting bodies, glutamate was the most abundant. Volatile compounds, chemical compositions, and nutritional values of T. matsutake varied with age and geographical origin and can serve as chemical indicators for classication of T. matsutake from different geographical areas and at different stages of maturity.

Transfer Printing Methods for Flexible Thin Film Solar Cells: Basic Concepts and Working Principles

Lee, Chi Hwan,Kim, Dong Rip,Zheng, Xiaolin American Chemical Society 2014 ACS NANO Vol.8 No.9

<P>Fabricating thin film solar cells (TFSCs) on flexible substrates will not only broaden the applications of solar cells, but also potentially reduce the installation cost. However, a critical challenge for fabricating flexible TFSCs on flexible substrates is the incompatibility issues between the thermal, mechanical, and chemical properties of these substrates and the fabrication conditions. Transfer printing methods, which use conventional substrates for the fabrication and then deliver the TFSCs onto flexible substrates, play a key role to overcome these challenges. In this review, we discuss the basic concepts and working principles of four major transfer printing methods associated with (1) transfer by sacrificial layers, (2) transfer by porous Si layer, (3) transfer by controlled crack, and (4) transfer by water-assisted thin film delamination. We also discuss the challenges and opportunities for implementing these methods for practical solar cell manufacture.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2014/ancac3.2014.8.issue-9/nn5037587/production/images/medium/nn-2014-037587_0007.gif'></P>

Effect of Glucagon-like Peptide 2 on Tight Junction in Jejunal Epithelium of Weaned Pigs though MAPK Signaling Pathway

Yu, Changsong,Jia, Gang,Jiang, Yi,Deng, Qiuhong,Chen, Zhengli,Xu, Zhiwen,Chen, Xiaolin,Wang, Kangning Asian Australasian Association of Animal Productio 2014 Animal Bioscience Vol.27 No.5

The glucagon-like peptide 2 (GLP-2) that is expressed in intestine epithelial cells of mammals, is important for intestinal barrier function and regulation of tight junction (TJ) proteins. However, there is little known about the intracellular mechanisms of GLP-2 in the regulation of TJ proteins in piglets' intestinal epithelial cells. The purpose of this study is to test the hypothesis that GLP-2 regulates the expressions of TJ proteins in the mitogen-activated protein kinase (MAPK) signaling pathway in piglets' intestinal epithelial cells. The jejunal tissues were cultured in a Dulbecco's modified Eagle's medium/high glucose medium containing supplemental 0 to 100 nmol/L GLP-2. At 72 h after the treatment with the appropriate concentrations of GLP-2, the mRNA and protein expressions of zonula occludens-1 (ZO-1), occludin and claudin-1 were increased (p<0.05). U0126, an MAPK kinase inhibitor, prevented the mRNA and protein expressions of ZO-1, occludin, claudin-1 increase induced by GLP-2 (p<0.05). In conclusion, these results indicated that GLP-2 could improve the expression of TJ proteins in weaned pigs' jejunal epithelium, and the underlying mechanism may due to the MAPK signaling pathway.

Effect of Interfacial Blocking Layer Morphology on the Solar Peroxydisulfate Production of WO₃ Nanoflakes

Ahn, Sung Hoon,Zhao, Jiheng,Kim, Jong Hak,Zheng, Xiaolin Pergamon Press 2017 Electrochimica Acta Vol. No.

<P><B>Abstract</B></P> <P>Herein, we investigate the morphological effect of WO<SUB>3</SUB> interfacial blocking layer on the PEC performance of WO<SUB>3</SUB> nanoflakes grown on fluorine-doped tin oxide (FTO) glass as a model photoanode system. We found that the mesoporous WO<SUB>3</SUB> interfacial blocking layer is much more effective than the random WO<SUB>3</SUB> nanoparticle interfacial layer in reducing the interfacial recombination. With the mesoporous interfacial blocking layer, the photocurrent density of WO<SUB>3</SUB> photoanode reaches 2.6mAcm<SUP>−2</SUP> at 1.23V vs RHE. This PEC system in 1 M H<SUB>2</SUB>SO<SUB>4</SUB> solution produces high-value added peroxydisulfate (S<SUB>2</SUB>O<SUB>8</SUB> <SUP>2−</SUP>) and hydrogen efficiently at over ∼95% faradaic efficiency.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The pivotal role of interfacial layer in photoelectrochemical cells is investigated. </LI> <LI> Amphiphilic graft copolymer self-assembly is used as a sacrificial template. </LI> <LI> The continuous WO<SUB>3</SUB> interfacial layer is combined to nanoflakes grown on top. </LI> <LI> The interfacial properties are found to be significantly enhanced. </LI> <LI> This PEC system efficiently produces peroxydisulfate (S<SUB>2</SUB>O<SUB>8</SUB> <SUP>2−</SUP>) and hydrogen. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Back-analysis by UDEC of the Failure Process of Wangjiayan Co-seismic Landslide during 2008.5.12 Wenchuan Earthquake.

( Yu Zou ),( Shengwen Qi ),( Songfeng Guo ),( Zhifa Zhan ),( Xiaolin Huang ),( Bowen Zheng ),( Ning Liang ),( Jiaguo Xia ),( Xingxing Li ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

Strong earthquakes such as the 2008 Wenchuan earthquake often induced numerous landslides, which resulted in a large number of casualties and property losses. Under a strong earthquake, a rock slope often produced a dynamic progressive failure. Understanding the process of the dynamic progressive failure of the rock slope is of great significance for the prediction and prevention of the co-seismic landslide. Generally, the numerical method is a feasible and economic alternative to solve this problem. However, previous studies presumed the failure surface and area in the numerical model, which cannot reproduce the dynamic progressive failure of the rock slope. In this paper, we applied the Universal Discrete Element method (UDEC) was adopted to quantitatively characterize the dynamic progressive failure process of the Wangjiayan co-seismic landslide triggered by 2008 Wenchan earthquake. Different from previous studies, there exists no presumed failure surface and area was was presumed in the UDEC model. The initiation, coalescence of the local fractures and the formation of the final failure surface were well simulated in a real-time way. Some key factors influencing the dynamic progressive failure of the rock slope were systematically explored. This study provided a new insight to understand the disaster-pregnant mechanism, evolution, and formation of the co-seismic landslide.

Sol-Flame Synthesis: A General Strategy To Decorate Nanowires with Metal Oxide/Noble Metal Nanoparticles

Feng, Yunzhe,Cho, In Sun,Rao, Pratap M.,Cai, Lili,Zheng, Xiaolin American Chemical Society 2013 Nano letters Vol.13 No.3

<P>The hybrid structure of nanoparticle-decorated nanowires (NP@NW) combines the merits of large specific surface areas for NPs and anisotropic properties for NWs and is a desirable structure for applications including batteries, dye-sensitized solar cells, photoelectrochemical water splitting, and catalysis. Here, we report a novel <I>sol-flame</I> method to synthesize the NP@NW hybrid structure with two unique characteristics: (1) large loading of NPs per NW with the morphology of NP chains fanning radially from the NW core and (2) intimate contact between NPs and NWs. Both features are advantageous for the above applications that involve both surface reactions and charge transport processes. Moreover, the sol-flame method is simple and general, with which we have successfully decorated various NWs with binary/ternary metal oxide and even noble metal NPs. The unique aspects of the sol-flame method arise from the ultrafast heating rate and the high temperature of flame, which enables rapid solvent evaporation and combustion, and the combustion gaseous products blow out NPs as they nucleate, forming the NP chains around NWs.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2013/nalefd.2013.13.issue-3/nl300060b/production/images/medium/nl-2012-00060b_0002.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl300060b'>ACS Electronic Supporting Info</A></P>

Three-Dimensional Hetero-Integration of Faceted GaN on Si Pillars for Efficient Light Energy Conversion Devices

Kim, Dong Rip,Lee, Chi Hwan,Cho, In Sun,Jang, Hanmin,Jeon, Min Soo,Zheng, Xiaolin American Chemical Society 2017 ACS NANO Vol.11 No.7

<P>An important pathway for cost-effective light energy conversion devices, such as solar cells and light emitting diodes, is to integrate III-V (e.g., GaN) materials on Si substrates. Such integration first necessitates growth of high crystalline III-V materials on Si, which has been the focus of many studies. However, the integration also requires that the final III-V/Si structure has a high light energy conversion efficiency. To accomplish these twin goals, we use single-crystalline microsized Si pillars as a seed layer to first grow faceted Si structures, which are then used for the heteroepitaxial growth of faceted GaN films. These faceted GaN films on Si have high crystallinity, and their threading dislocation density is similar to that of GaN grown on sapphire. In addition, the final faceted GaN/Si structure has great light absorption and extraction characteristics, leading to improved performance for GaN-on-Si light energy conversion devices.</P>

Rapid Formation of a Disordered Layer on Monoclinic BiVO₄ : Co-Catalyst-Free Photoelectrochemical Solar Water Splitting

Kim, Jung Kyu,Cho, Yoonjun,Jeong, Myung Jin,Levy-Wendt, Ben,Shin, Dongguen,Yi, Yeonjin,Wang, Dong Hwan,Zheng, Xiaolin,Park, Jong Hyeok Wiley (John WileySons) 2018 ChemSusChem Vol.11 No.5

<P>A surface disordered layer is a plausible approach to improve the photoelectrochemical performance of TiO2. However, the formation of a crystalline disordered layer in BiVO4 and its effectiveness towards photoelectrochemical water splitting has remained a big challenge. Here, we report a rapid solution process (within 5s) that is able to form a disordered layer of a few nanometers thick on the surface of BiVO4 nanoparticles using a specific solution with a controllable reducing power. The disordered layer on BiVO4 alleviates charge recombination at the electrode-electrolyte interface and reduces the onset potential greatly, which in turn results in a photocurrent density of approximately 2.3 mA cm(-2) at 1.23 V versus the reversible hydrogen electrode (RHE). This value is 2.1 times higher than that of bare BiVO4. The enhanced photoactivity is attributed to the increased charge separation and transfer efficiencies, which resolve the intrinsic drawbacks of bare BiVO4 such as the short hole diffusion length of around 100 nm and poor surface oxygen evolution reactivity.</P>

Branched TiO₂ Nanorods for Photoelectrochemical Hydrogen Production

Cho, In Sun,Chen, Zhebo,Forman, Arnold J.,Kim, Dong Rip,Rao, Pratap M.,Jaramillo, Thomas F.,Zheng, Xiaolin American Chemical Society 2011 Nano letters Vol.11 No.11

<P>We report a hierarchically branched TiO<SUB>2</SUB> nanorod structure that serves as a model architecture for efficient photoelectrochemical devices as it simultaneously offers a large contact area with the electrolyte, excellent light-trapping characteristics, and a highly conductive pathway for charge carrier collection. Under Xenon lamp illumination (UV spectrum matched to AM 1.5G, 88 mW/cm<SUP>2</SUP> total power density), the branched TiO<SUB>2</SUB> nanorod array produces a photocurrent density of 0.83 mA/cm<SUP>2</SUP> at 0.8 V versus reversible hydrogen electrode (RHE). The incident photon-to-current conversion efficiency reaches 67% at 380 nm with an applied bias of 0.6 V versus RHE, nearly two times higher than the bare nanorods without branches. The branches improve efficiency by means of (i) improved charge separation and transport within the branches due to their small diameters, and (ii) a 4-fold increase in surface area which facilitates the hole transfer at the TiO<SUB>2</SUB>/electrolyte interface.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2011/nalefd.2011.11.issue-11/nl2029392/production/images/medium/nl-2011-029392_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl2029392'>ACS Electronic Supporting Info</A></P>