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1.
PAPER CURRENT
Ultra-low loading of copper modified TiO2/CeO2 catalysts for low-temperature selective catalytic reduction of NO by NH3 (2017)
Elsevier
Publication Date: 2017-02-25
Description: Publication date: 15 June 2017 Source: Applied Catalysis B: Environmental, Volume 207 Author(s): Lulu Li, Lei Zhang, Kaili Ma, Weixin Zou, Yuan Cao, Yan Xiong, Changjin Tang, Lin Dong A series of ultra-low content copper-modified TiO 2 /CeO 2 catalysts were prepared by wet impregnation method and tested for selective catalytic reduction of NO by NH 3 . The catalyst with a Cu/Ce molar ratio of 0.005 showed the best low-temperature activity and excellent sulfur-poisoning resistance. It was worth noting that the very small amounts of copper addition can lead to three times the activity at low temperature. The prepared catalysts were characterized by XRD, BET, Raman, XPS, NH 3 -TPD and the results revealed that the introduction of copper increased the amount of surface adsorbed oxygen and Ce 3+ species on the catalyst surface and generated more Brønsted acid sites. The redox and surface acidic properties were also improved by the addition of Cu. All these factors played important roles in enhancing NH 3 -SCR performance of TiO 2 -CuO/CeO 2 catalysts. Furthermore, in situ DRIFT experiments demonstrated that Cu doping enhanced the adsorption capacity of NH 3 while the appearance of CuO weakened the adsorption ability of bridging nitrates, both the two factors synergistically facilitated the NH 3 -SCR reaction proceed smoothly via the Eley-Rideal pathway. Graphical abstract
Print ISSN: 0926-3373
Electronic ISSN: 1873-3883
Topics: Chemistry and Pharmacology
Published by Elsevier
2.
PAPER CURRENT
Coral-inspired nanoscale design of porous SnS2 for photocatalytic reduction and removal of aqueous Cr (VI) (2017)
Elsevier
Publication Date: 2017-02-25
Description: Publication date: 15 June 2017 Source: Applied Catalysis B: Environmental, Volume 207 Author(s): Jiafu Qu, Dongyun Chen, Najun Li, Qingfeng Xu, Hua Li, Jinghui He, Jianmei Lu Frequent industrial discharge of various contaminants such as heavy metals into water resources has caused severe environmental damage. In this study, a unique porous corallite-like nanocomposite (SPNH-MOSF@SnS 2 ) was successfully fabricated via surface modification of visible-light-driven photocatalyst (SnS 2 ) and chelating ligand (spirobenzopyran derivative, SPNH) on macroporous ordered siliceous foam (MOSF). In our approach, SnS 2 was selected as the photocatalyst due to its high visible light induced photocatalytic activity. SPNH was modified because it could selectively chelate soluble Cr (III) when exposed to ultraviolet light. This unique nanocomposite could be used for highly efficient reduction and removal of hexavalent chromium [Cr (VI)] from wastewater, especially under the mildly acidic condition. The results indicate encouraging applications of this as-prepared new nanocomposite for treating Cr (VI) containing wastewater. Graphical abstract
Print ISSN: 0926-3373
Electronic ISSN: 1873-3883
Topics: Chemistry and Pharmacology
Published by Elsevier
3.
PAPER CURRENT
Graphene quantum dots modified mesoporous graphite carbon nitride with significant enhancement of photocatalytic activity (2017)
Elsevier
Publication Date: 2017-02-25
Description: Publication date: 15 June 2017 Source: Applied Catalysis B: Environmental, Volume 207 Author(s): Jinyuan Liu, Hui Xu, Yuanguo Xu, Yanhua Song, Jiabiao Lian, Yan Zhao, Liang Wang, Liying Huang, Haiyan Ji, Huaming Li Hydroxyl-graphene quantum dots (GQDs) modified mesoporous graphitic carbon nitride (mpg-C 3 N 4 ) composites were fabricated through electrostatic interactions. A variety of techniques were applied to discuss systematic effect on the morphology, optical, electronic properties and structure of GQDs/mpg-C 3 N 4 composites. Remarkably, the 0.5 wt% GQDs/mpg-C 3 N 4 composites exhibited higher photocatalytic activity than that of the pure mpg-C 3 N 4 by using rhodamine B (RhB) and colorless tetracycline hydrochloride (TC) as pollutants under visible light irradiation. The results indicated that uniform dispersion of GQDs on the surface of mpg-C 3 N 4 and intimate contact between the two materials contributed to the enhanced activity. Radical trapping experiments and electron spin resonance tests both certified that the GQDs/mpg-C 3 N 4 composites can generate more O 2 − species and a small fraction of holes for photocatalytic degradation. Graphical abstract
Print ISSN: 0926-3373
Electronic ISSN: 1873-3883
Topics: Chemistry and Pharmacology
Published by Elsevier
4.
PAPER CURRENT
MIL-68(Fe) as an efficient visible-light-driven photocatalyst for the treatment of a simulated waste-water contain Cr(VI) and Malachite Green (2017)
Elsevier
Publication Date: 2017-02-25
Description: Publication date: 5 June 2017 Source: Applied Catalysis B: Environmental, Volume 206 Author(s): Fenfen Jing, Ruowen Liang, Jinhua Xiong, Rui Chen, Shiying Zhang, Yanhua Li, Ling Wu A highly effective Iron Metal-Framework photocatalyst (MIL-68(Fe)) has been successfully prepared via a facile solvothermal method under acidic condition. The UV–vis diffuse reflectance spectrum reveals that the absorption edge of MIL-68(Fe) is 440 nm. The flat-band potential of MIL-68(Fe) is −0.6 V vs. NHE at pH = 6.8, which is more negative than the redox potential of Cr(VI)/Cr(III) (+0.51 V, pH = 6.8). Consequently, it is thermodynamically permissible for the transformation of photogenerated electrons to the Cr(VI) to produce Cr(III). Moreover, MIL-68(Fe) could perform as an efficient photocatalyst towards the reduction of Cr(VI) aqueous with a wide pH range. After 5 min of visible light illumination (λ > 420 nm), almost 100% Cr(VI) can convert to Cr(III) with (NH 4 ) 2 C 2 O 4 as a scavenger (pH = 3), which is also higher than that of N-doped TiO 2 (50%) and ZnO (7.6%) under identical conditions. Furthermore, MIL-68(Fe) is proved to perform as a highly efficient photocatalyst for remove of different aqueous contaminant with malachite green (MG) as a scavenger. Finally, a possible reaction mechanism has also been investigated in detail. Graphical abstract
Print ISSN: 0926-3373
Electronic ISSN: 1873-3883
Topics: Chemistry and Pharmacology
Published by Elsevier
5.
PAPER CURRENT
Energy demand profile generation with detailed time resolution at an urban district scale: A reference building approach and case study (2017)
Elsevier
Publication Date: 2017-02-25
Description: Publication date: 1 May 2017 Source: Applied Energy, Volume 193 Author(s): Georgios Kazas, Enrico Fabrizio, Marco Perino The energy demand in urban areas has increased dramatically over the last few decades because of the intensive urbanization that has taken place. Because of this, the European Union has introduced directives pertaining to the energy performance of buildings and has identified demand side management as a significant tool for the optimization of the energy demand. Demand side management, together with thermal energy storage and renewable energy technologies, have mainly been studied so far at a building scale. In order to study and define potential demand side management strategies at an urban scale, an integrated urban scale assessment needs to be conducted. DiDeProM, a model that can be used to generate detailed thermal energy demand profiles, at an urban district scale, has been developed in the current study. It is a bottom-up engineering model, based on samples of the representative building technique. A parametric analysis of the important variables of building energy performance at an urban scale has then been carried out. This has generated a database of normalized thermal energy demand profiles with an hourly time resolution. The final step of the process includes the generation of a detailed overall thermal energy demand profile at an urban district scale. DiDeProM was applied to a block of buildings in Turin (Italy) as a case study. After the calibration of the simulation model on real monitored data, a parametric analysis on 300 scenarios for a reference building was conducted, generating a database of seasonal thermal heating energy demand profiles with hourly time steps. An average hourly heating profile was generated from this database according to a specific aggregation approach. The DiDeProM application indicated that the model works properly at the scale of a typical small block of buildings, and it is able to generate a total thermal energy demand profile, with detailed time resolution, at an urban district scale. These profiles will be used to create demand side management strategies that will integrate thermal energy storage and renewable energy technologies at a district scale.
Print ISSN: 0306-2619
Electronic ISSN: 1872-9118
Topics: Energy, Environment Protection, Nuclear Power Engineering
Published by Elsevier
6.
PAPER CURRENT
A numerical study of the effects of using hydrogen, reformer gas and nitrogen on combustion, emissions and load limits of a heavy duty natural gas/diesel RCCI engine (2017)
Elsevier
Publication Date: 2017-02-25
Description: Publication date: 1 May 2017 Source: Applied Energy, Volume 193 Author(s): Pourya Rahnama, Amin Paykani, Rolf D. Reitz The purpose of this research was to analyze numerically the effect of adding nitrogen, hydrogen, reformer gas and hydrogen and nitrogen mixtures on the combustion and exhaust emissions properties of a natural gas-diesel dual-fuel reactivity controlled compression ignition (RCCI) engine at different engine loads. By using natural gas, emissions and engine performance suffer at low loads due to its lower reactivity and higher ignition delay compared to gasoline. However, the use of hydrogen and syngas (reformer gas) as an additive can improve the combustion process of the engine at low loads. On the other hand, RCCI engine operation is limited to low-medium loads due to high peak pressure rise rates and high ringing intensity at high engine loads. The use of nitrogen as a dilution gas can mitigate this behavior at engine high load operation. The results obtained indicate that combustion was improved at low engine load by using hydrogen and syngas and CO and HC emissions are reduced. In addition, it was found that stable combustion and a low pressure rise rate could be achieved at 17 bar IMEP at the expense of higher carbon emissions with nitrogen-rich intake air. The effect of adding hydrogen, reformer gas, nitrogen, and a mixture of hydrogen and nitrogen on ignition delay, combustion duration, combustion efficiency, gross indicated efficiency, pressure rise rate, and ringing intensity was also investigated. It was indicated that how the gases produced by catalytic fuel reformer will allow RCCI engine to operate at various loads with low emissions.
Print ISSN: 0306-2619
Electronic ISSN: 1872-9118
Topics: Energy, Environment Protection, Nuclear Power Engineering
Published by Elsevier
7.
PAPER CURRENT
Surface flashover performance of epoxy resin microcomposites improved by electron beam irradiation (2017)
Elsevier
Publication Date: 2017-02-25
Description: Publication date: 1 June 2017 Source: Applied Surface Science, Volume 406 Author(s): Yin Huang, Daomin Min, Shengtao Li, Zhen Li, Dongri Xie, Xuan Wang, Shengjun Lin The influencing mechanism of electron beam irradiation on surface flashover of epoxy resin/Al 2 O 3 microcomposite was investigated. Epoxy resin/Al 2 O 3 microcomposite samples with a diameter of 50 mm and a thickness of 1 mm were prepared. The samples were irradiated by electron beam with energies of 10 and 20 keV and a beam current of 5 μA for 5 min. Surface potential decay, surface conduction, and surface flashover properties of untreated and irradiated samples were measured. Both the decay rate of surface potential and surface conductivity decrease with an increase in the energy of electron beam. Meanwhile, surface flashover voltage increase. It was found that both the untreated and irradiated samples have two trap centers, which are labeled as shallow and deep traps. The increase in the energy and density of deep surface traps enhance the ability to capture primary emitted electrons. In addition, the decrease in surface conductivity blocks electron emission at the cathode triple junction. Therefore, electron avalanche at the interface between gas and an insulating material would be suppressed, eventually improving surface flashover voltage of epoxy resin microcomposites.
Print ISSN: 0169-4332
Topics: Physics
Published by Elsevier
8.
PAPER CURRENT
Surface-conduction electron-emitter characteristics and fabrication based on vertically aligned carbon nanotube arrays (2017)
Elsevier
Publication Date: 2017-02-25
Description: Publication date: 1 June 2017 Source: Applied Surface Science, Volume 406 Author(s): Yi-Ting Shih, Kuan-Wei Li, Shin-ichi Honda, Pao-Hung Lin, Ying-Sheng Huang, Kuei-Yi Lee The carbon nanotube (CNT) has replaced palladium oxide (PdO) as the electrode material for surface-conduction electron-emitter (SCE) applications. Vertically aligned CNT arrays with a delta-star arrangement were patterned and synthesized onto a quartz substrate using photolithography and thermal chemical vapor deposition. Delta-star shaped VACNT arrays with 20° tips are used as cathodes that easily emit electrons because of their high electrical field gradient. In order to improve the field emission and secondary electrons (SEs) in SCE applications, magnesium oxide (MgO) nanostructures were coated onto the VACNT arrays to promote the surface-conduction electron-emitter display (SED) efficiency (η). According to the definition of η in SCE applications, in this study, the η was stably maintained in the 75–85% range. The proposed design provides a facile new method for developing SED applications. Graphical abstract
Print ISSN: 0169-4332
Topics: Physics
Published by Elsevier
9.
PAPER CURRENT
High performance and durability of order-structured cathode catalyst layer based on TiO2@PANI core-shell nanowire arrays (2017)
Elsevier
Publication Date: 2017-02-25
Description: Publication date: 1 June 2017 Source: Applied Surface Science, Volume 406 Author(s): Ming Chen, Meng Wang, Zhaoyi Yang, Xindong Wang In this paper, an order-structured cathode catalyst layer consisting of Pt-TiO 2 @PANI core-shell nanowire arrays that in situ grown on commercial gas diffusion layer (GDL) are prepared and applied to membrane electrode assembly (MEA) of proton exchange membrane fuel cell (PEMFC). In order to prepare the TiO 2 @PANI core-shell nanowire arrays with suitable porosity and prominent conductivity, the morphologies of the TiO 2 nanoarray and electrochemical polymerization process of aniline are schematically investigated. The MEA with order-structured cathode catalyst layer is assembled in the single cell to evaluate the electrochemical performance and durability of PEMFC. As a result, the PEMFC with order-structured cathode catalyst layer shows higher peak power density (773.54 mW cm −2 ) than conventional PEMFC (699.30 mW cm −2 ). Electrochemically active surface area (ECSA) and charge transfer impedance (R ct ) are measured before and after accelerated degradation test (ADT), and the corresponding experimental results indicate the novel cathode structure exhibits a better stability with respect to conventional cathode. The enhanced electrochemical performance and durability toward PEMFC can be ascribed to the order-structured cathode nanoarray structure with high specific surface area increases the utilization of catalyst and reduces the tortuosity of transport pathways, and the synergistic effect between TiO 2 @PANI support and Pt nanoparticles promotes the high efficiency of electrochemical reaction and improves the stability of catalyst. This research provides a facile and controllable method to prepare order-structured membrane electrode with lower Pt loading for PEMFC in the future. Graphical abstract
Print ISSN: 0169-4332
Topics: Physics
Published by Elsevier
10.
PAPER CURRENT
Geospatial tool-based morphometric analysis using SRTM data in Sarabanga Watershed, Cauvery River, Salem district, Tamil Nadu, India (2017)
Springer
Publication Date: 2017-02-25
Description: A morphometric analysis of Sarabanga watershed in Salem district has been chosen for the present study. Geospatial tools, such as remote sensing and GIS, are utilized for the extraction of river basin and its drainage networks. The Shuttle Radar Topographic Mission (SRTM-30 m resolution) data have been used for morphometric analysis and evaluating various morphometric parameters. The morphometric parameters of Sarabanga watershed have been analyzed and evaluated by pioneer methods, such as Horton and Strahler. The dendritic type of drainage pattern is draining the Sarabanga watershed, which indicates that lithology and gentle slope category is controlling the study area. The Sarabanga watershed is covered an area of 1208 km 2 . The slope of the watershed is various from 10 to 40% and which is controlled by lithology of the watershed. The bifurcation ratio ranges from 3 to 4.66 indicating the influence of geological structure and suffered more structural disturbances. The form factor indicates elongated shape of the study area. The total stream length and area of watershed indicate that mean annual rainfall runoff is relatively moderate. The basin relief expressed that watershed has relatively high denudation rates. The drainage density of the watershed is low indicating that infiltration is more dominant. The ruggedness number shows the peak discharges that are likely to be relatively higher. The present study is very useful to plan the watershed management.
Print ISSN: 2190-5487
Electronic ISSN: 2190-5495
Topics: Energy, Environment Protection, Nuclear Power Engineering
Published by Springer