2017 Vol. 2, No. 4

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A new era of precise liquid regulation: Quasi-liquid
Suojiang Zhang, Yanlei Wang, Hongyan He, Feng Huo, Yumiao Lu, Xiaochun Zhang, Kun Dong
2017, 2(4): 329-330. doi: 10.1016/j.gee.2017.09.001
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Review article
A review on photoelectrochemical cathodic protection semiconductor thin films for metals
Yuyu Bu, Jin-Ping Ao
2017, 2(4): 331-362. doi: 10.1016/j.gee.2017.02.003
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Photoelectrochemical (PEC) cathodic protection is considered as an environment friendly method for metals anticorrosion. In this technology, a n-type semiconductor photoanode provides the photogenerated electrons for metal to achieve cathodic protection. Comparing with traditional PEC photoanode for water splitting, it requires the photoanode providing a suitable cathodic potential for the metal, instead of pursuit ultimate photon to electric conversion efficiency, thus it is a more possible PEC technology for engineering application. To date, great efforts have been devoted to developing novel n-type semiconductors and advanced modification method to improve the performance on PEC cathodic protection metals. Herein, recent progresses in this field are summarized. We highlight the fabrication process of PEC cathodic protection thin film, various nanostructure controlling, doping, compositing methods and their operation mechanism. Finally, the current challenges and future potential works on improving the PEC cathodic protection performance are discussed.
Research paper
Guidelines for rational design of high-performance absorbents: A case study of zeolite adsorbents for emerging pollutants in water
Xiaoxuan Wei, Ya Wang, Arturo J. Hernández-Maldonado, Zhongfang Chen
2017, 2(4): 363-369. doi: 10.1016/j.gee.2017.05.002
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Rational design is important to achieve high-performance sorbents used to remove the contaminants of emerging concern (CECs) from water. However, it is hard to propose effective design guidelines due to the lack of a clear understanding of the interaction mechanisms. By means of systematic quantum chemical computations, as a case study, we investigated the interactions between zeolite X/M–zeolite X (Si/Al = 1, M = Cu2+ and Ni2+) and three commonly used CECs (namely salicylic acid, carbamazepine and ciprofloxacin) in water to clarify the adsorption mechanisms. Our computations found that anionic salicylic acid cannot be adsorbed by neither zeolite X nor M–zeolite X in neutral water due to the high electrostatic repulsion. In comparison, carbamazepine and ciprofloxacin have favorable binding energies with both zeolite X and M–zeolite X, and their interactions with M–zeolite X are stronger due to the joint effects of H-bond, metal complexation and electrostatic interaction. The adsorption loading of ciprofloxacin, which has a large molecular size, on M–zeolite X is limited due to the steric hindrance. In general, steric hindrance, electrostatic interaction, H-bond and metal complexation are dominant factors for the examined systems in this study. Thus, for the design of high-performance absorbing materials, we should fully consider the molecular properties of pollutants (molecular size, surface electrostatic potential and atomic type, etc.), and properly enhance the favorable effects and avoid the unfavorable factors as much as possible under the guidance of the interaction mechanisms.
Synthesis of polyurea from 1,6-hexanediamine with CO2 through a two-step polymerization
Shan Jiang, Ruhui Shi, Haiyang Cheng, Chao Zhang, Fengyu Zhao
2017, 2(4): 370-376. doi: 10.1016/j.gee.2017.05.001
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Activation and transformation of CO2 is one of the important issues in the field of green and sustainable chemistry. Herein, CO2 as a carbon-oxygen resource was converted to CO2-polyurea with 1,6-hexanediamine through a two-step polymerization. The reaction parameters such as temperature, pressure and reaction time were examined; and several kinds of catalysts were screened in the absence and presence of NMP solvent. The formed oligomer and the final polyurea were characterized by FT-IR, VT-DRIFTS, NMR, XRD, AFM and their thermal properties were examined by TGA and DSC. It was confirmed that the final polyurea has a high thermal stability; the melting temperature is 269 °C and the decomposition temperature is above 300 °C. It is a brittle polymer with a tensile strength of 18.35 MPa at break length of 1.64%. The polyurea has a stronger solvent resistance due to the ordered hydrogen bond in structure. The average molecular weight should be enhanced in the post-polymerization as the appearance, hydrogen bond intensity, crystallinity, melting point and the thermal stability changed largely compared to the oligomer. The present work provides a new kind of polyurea, it is expected to have a wide application in the field of polymer materials.
MnO/N–C anode materials for lithium-ion batteries prepared by cotton-templated combustion synthesis
Cheng-Gong Han, Chunyu Zhu, Yoshitaka Aoki, Hiroki Habazaki, Tomohiro Akiyama
2017, 2(4): 377-386. doi: 10.1016/j.gee.2017.08.004
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We herein report a facile one-pot synthesis of MnO/N-doped carbon (N–C) composites via a sustainable cotton-template glycine–nitrate combustion synthesis to yield superior anode materials for Li ion batteries. MnO nanoparticles with several nanometers were well-embedded in a porous N-doped carbon matrix. It displays the unique characteristics, including the shortened Li+-ion transport path, increased contact areas with the electrolyte solution, inhibited volume changes and agglomeration of nanoparticles, as well as good conductivity and structural stability during the cycling process, thereby benefiting the superior cycling performance and rate capability. This favorable electrochemical performance of obtained MnO/N–C composites via a one-pot biomass-templated glycine/nitrate combustion synthesis renders the suitability as anode materials for Li-ion batteries.
Harvesting, sensing and regulating light based on photo-thermal effect of Cu@CuO mesh
Xuan Wu, Jie Xu, George Y. Chen, Rong Fan, Xiaokong Liu, Haolan Xu
2017, 2(4): 387-392. doi: 10.1016/j.gee.2017.02.002
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A system of light harvesting, sensing and regulating was designed based on the photo-thermal and Seebeck effect of flexible CuO nanostructures. Cu@CuO meshes were prepared via self-oxidation of Cu mesh and utilized as the photo-thermal material. Upon irradiation by visible light, the temperature of the Cu@CuO mesh dramatically increases. The temperature difference between the irradiated and non-irradiated parts of the Cu@CuO mesh produced a measurable voltage output due to the Seebeck effect. The generated voltage was then converted into a digital signal to control a rotary neutral-density disc to filter the received light. This enabled regulation of the intensity of the incident light at a selected region. This system is cost effective and has potential applications in greenhouses, factories and smart buildings to minimize energy consumption and improve wellbeing.
Laccase immobilized on magnetic nanoparticles by dopamine polymerization for 4-chlorophenol removal
Di Zhang, Manfeng Deng, Hongbin Cao, Songping Zhang, He Zhao
2017, 2(4): 393-400. doi: 10.1016/j.gee.2017.04.001
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In this work, a new immobilization method based on dopamine (DA) self-polymerization was developed for laccase immobilization on magnetic nanoparticles (Fe3O4 NPs). To optimize the immobilization condition including reaction pH, DA concentration and enzyme concentration, a central composite response surface method was applied. The optimal condition was determined as pH value of 5.92, laccase concentration of 0.25 mg mL −1 and DA concentration of 12.74 mg mL−1, under which a high enzyme activity recovery of 88.17% was obtained. By comparing with free laccase, the stabilities of immobilized laccase towards pH, thermostability, storage were enhanced significantly. Approximately 60% of relative activity for immobilized laccase was remained after being incubated for 6 h at 50 °C, but the free laccase only remained 25%. After 40 days of storage at 4 °C, the laccase immobilized by DA kept about 89% of its original activity, but the free laccase only retained 48%. After recycled 10 times, the relative activity of immobilized laccase still retained 70%. The immobilized laccase was then applied to catalyze the degradation of 4-chlorophenol (4-CP), 86% percentage of 4-CP was removed within 2 h. After degraded 10 times, the relative activity of immobilized laccase still remained 64% of its initial activity, which exhibits an excellent reusability and operational stability.
Facile and controllable synthesis of BaCO3 crystals superstructures using a CO2-storage material
Feng Sha, Bo Guo, Jing Zhao, Fei Zhang, Xianshu Qiao, Liang Ma, Chang Liu, Jianbin Zhang
2017, 2(4): 401-411. doi: 10.1016/j.gee.2017.03.004
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We here report a new CO2 capture and storage method that converts CO2 into a novel alkyl carbonate salt, denoted as CO2SM, by a system consisting of equimolar 1,4-butanediol (BDO) and 1,2-ethylenediamine (EDA). This novel CO2SM was then used to prepare BaCO3 crystals through a simple and fast hydrothermal synthesis under mild conditions. The CO2SM was both the source of CO2 and the modifier to regulate the nucleation and growth of BaCO3 crystals. The morphology of the BaCO3 crystals could be tuned from rod to shuttle by adjusting the key influencing factors, including CO2SM concentration, mineralization temperature, and mineralization time. A possible mechanism for the synthesis of BaCO3 crystals from the CO2SM was also presented. After the BaCO3 crystals were isolated, the filtrate of the hydrothermal reaction could be recycled to again absorb CO2 and prepare BaCO3 crystals of the same polymorph. This novel approach appears promising for preparing well-formed metal carbonates.
The passivation mechanism of Fe in the acidic AlCl3-EMIC ionic liquid
Dongpeng Xue, Yang Yang, Guoping Ling
2017, 2(4): 412-418. doi: 10.1016/j.gee.2017.08.003
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The passivation behavior of Fe in the acidic AlCl3-1-ethyl-3-methyl-imidazolium chloride (AlCl3-EMIC) ionic liquid was studied by linear sweep voltammetry and chonopotentiometry. Various approaches were used to characterize the composition and morphology of passive film formed on the Fe electrode, such as scanning electron microscopy (SEM), Raman spectra and X-ray Photoelectron Spectroscopy (XPS). The results showed that the critical passivation potential of Fe shifted to more negative when the molar ratio of AlCl3:EMIC changing from 2 to 1.3. A film with a light yellow color was observed on the surface of the Fe electrode after passivation. The composition of the passive film was demonstrated to be FeCl2. The passive film was composed of particulate FeCl2 with average diameter of about 500 nm. The formation of FeCl2 film was attributed to the variation of the electrolyte Lewis acidity from acidic to neutral at the interface during the dissolution process of Fe. The reason caused the variation of the electrolyte acidity was discussed.
Efficient and recyclable Rh-catalytic system with involvement of phosphine-functionalized phosphonium-based ionic liquids for tandem hydroformylation–acetalization
Peng Wang, Xia Chen, Dong-Liang Wang, Yong-Qi Li, Ye Liu
2017, 2(4): 419-427. doi: 10.1016/j.gee.2017.01.003
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The phosphine-functionalized phosphonium-based ionic liquids ( dppm-Q , dppe-Q , dppp-Q and dppb-Q ) as the bi-functional ligands enable the efficient one-pot tandem hydroformylation–acetalization. It was found that, in dppm-Q , dppe-Q , dppp-Q and dppb-Q , the incorporated phosphino-fragments were responsible for Rh-catalyzed hydroformylation and the phosphoniums were in charge of the subsequent acetalization as the Lewis acid catalysts. Moreover, the diphosphonium-based ionic liquid of dppb-DQ could be applied as a co-solvent to immobilize the Rh/ dppb-Q catalytic system with the advantages of the improved catalytic performance, the available catalyst recyclability, and the wide generality for the substrates.
Unsymmetrical donor–acceptor–donor–acceptor type indoline based organic semiconductors with benzothiadiazole cores for solution-processed bulk heterojunction solar cells
Wenqin Li, Wene Shi, Zihua Wu, Jinmin Wang, Min Wu, Wei-Hong Zhu
2017, 2(4): 428-435. doi: 10.1016/j.gee.2016.10.004
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Bulk heterojunction (BHJ) solar cells based on small molecules have attracted potential attention due to their promise of conveniently defined structures, high absorption coefficients, solution process-ability and easy fabrication. Three D–A–D–A type organic semiconductors ( WS-31 , WS-32 and WS-52 ) are synthesized, based on the indoline donor and benzotriazole auxiliary acceptor core, along with either bare thiophene or rigid cyclopentadithiophene as π bridge, rhodanine or carbonocyanidate as end-group. Their HOMO orbitals are delocalized throughout the whole molecules. Whereas the LUMOs are mainly localized on the acceptor part of structure, which reach up to benzothiadiazole, but no distribution on indoline donor. The first excitations for WS-31 and WS-32 are mainly originated by electron transition from HOMO to LUMO level, while for WS-52 , partly related to transition between HOMO and LUMO+1 level. The small organic molecules are applied as donor components in bulk heterojunction (BHJ) organic solar cells, using PC61BM as acceptor material to check their photovoltaic performances. The BHJ solar cells based on blended layer of WS-31 :PC61BM and WS-32 :PC61BM processed with chloroform show overall photoelectric conversion efficiency (PCE) of 0.56% and 1.02%, respectively. WS-32 based BHJ solar cells show a higher current density originated by its relatively larger driving force of photo-induced carrier in photo-active layer to LUMO of PC61BM.
Synergistic effect of polyoxometalate solution and TiO2 under UV irradiation to catalyze formic acid degradation and their application in the fuel cell and hydrogen evolution
Congmin Liu, Zhe Zhang, Wei Liu, Xu Du, Shi Liu, Yong Cui
2017, 2(4): 436-441. doi: 10.1016/j.gee.2016.12.003
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The synergistic effect of H3PMo12O40 or H3PW12O40 polyoxometalate solution (POM) and TiO2 to catalyze formic acid oxidation was investigated. Under UV irradiation, hole and electron were photogenerated by TiO2. Formic acid was oxided by the photogenerated hole and photogenerated electron was transferred to reduce polyoxometalate. With this design, formic acid can be converted into electricity in the fuel cell and hydrogen can be generated in the electrolysis cell without noble metal catalyst. Unlike other noble metal catalysts applied in the fuel cells and electrolysis cell, POM and TiO2 are stable and low cost. The maximum output power density of liquid formic acid fuel cell after 12 h UV irradiation is 5.21 mW/cm2 for phosphmolybdic acid and 22.81 mW/cm2 for phosphotungstic acid respectively. The applied potential for the hydrogen evolution is as low as 0.8 V for phosphmolybdic acid and 0.6 V for phosphotungstic acid.

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