IONICS
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2019
·Vol. 26
·期 2
·801-811
·
IF 2.289
Dai Jicui,Zhang Hongqiang,Sui Zhaobin,Hu Huili,Gao Peng,Zhu Yongming,Dong Yichao,Teng Xiangguo
In order to reduce the vanadium ion permeability while still keep its high stability, atom radical polymerization (ATRP) method was used to introduce zwitterionic sulfobetaine methacrylate (SBMA) onto the Nafion matrix in homogenous solution. The Nafion-grafted poly SBMA (N-g-PSBMA) solution was then used to blend with common Nafion solution to prepare Nafion/Nafion-g-PSBMA (N/N-g-PSBMA) amphoteric membranes by solution casting method. The grafted resins and membranes were characterized by attenuated total reflectance Fourier transform infrared spectra (ATR-FTIR), energy dispersive X-Ray spectroscopy (EDX), scanning electron microscopy (SEM), and water-contact angle analysis. The results prove that the SBMA has been successfully grafted onto the Nafion backbones. Furthermore, the N/N-g-PSBMA membranes have shown higher ion selectivity, coulombic efficiency, and energy efficiency than that of pure recast Nafion (r-Nafion) membrane for VRB application. At the current density of 40–80 mA cm −2 , the average energy efficiency of the VRB with N/N-g-PSBMA-20% membrane has reached up to 84.9%, which is 4.2% higher than that of the VRB with the r-Nafion membrane at the same current densities. Moreover, the 100-cycles charge-discharge test proves that the N/N-g-PSBMA-20% membrane possesses higher stability and capacity retention ability than that of r-Nafion membrane, confirming the great potential of such membranes for VRB application.
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CHEMOSPHERE
·
2019
·
IF 5.108
Yu Xie,Shuhan Peng,Yong Feng,Deli Wu
The degradation of carboxylic acid has been identified as one of the rate-determining steps in the mineralization of organic pollutants by ozonation . In this study, Ce(III)-doped graphitic carbon nitride (Ce–CN) composites with different Ce(III) contents were synthesized and used as catalysts for the ozonation of oxalate. The morphology and structure of the Ce–CN were comprehensively characterized using various techniques such as SEM, XRD , FTIR , and XPS. The results show that the structure of g-C 3 N 4 provided an ideal site for the accommodation of Ce(III) and thus facilitated the formation of surface hydroxyl groups. With 2.5%Ce–CN as a catalyst, the degradation efficiency of oxalate was increased by 47.1% after reaction for 30 min. The decomposition of ozone was accelerated in the presence of Ce–CN. Hydroxyl radicals were recorded by electron spin resonance and identified as the major actives species. Under the catalysis of 2.5%Ce–CN, the production of hydroxyl radicals was increased by 40%. The Ce(III) and surface hydroxyl groups that distributed uniformly on the surface of Ce–CN were speculated as the dual catalytic sites for the complexation of oxalate and activation of ozone, respectively. Ce–CN had a high stability and reutilization capability. It is proposed that a complex was formed between surface Ce(III) and oxalate, and this complex could be more easily attacked by the surrounding ozone and hydroxyl radicals than free oxalate. As oxalate is a typical recalcitrant carboxylic acid, the findings from this study are expected to promote the application of ozonation in the removal of organic pollutants.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
·
IF 14.229
Ming Lei,Zhiying Wang,Lihua Zhu,Wenshan Nie,Heqing Tang
Deep debromination of polybrominated diphenyl ethers (PBDEs) by visible light photocatalysis is still a challenge in the field of halogenated pollutants control. Here, an efficient photocatalyst (Pd/g-C 3 N 4 ) was prepared by a simple impregnation-chemical reduction method with bulk g-C 3 N 4 and PdCl 2 as precursors. Under preferred reaction conditions (visible light irradiation for 120 min), the use of the 0.5% Pd/g-C 3 N 4 composites (0.4 g L −1 ) yielded an almost complete debromination of BDE47 (10 μmol L −1 ) in methanol-water mixture, while the debromination of BDE47 did not occur on pure g-C 3 N 4 . A “Pd-promoted active H atom species attack and C-Br bond cleavage” route was proposed according to the identified degradation intermediates. A catalytic mechanism was further clarified: Pd nanoparticles exerted affinity interaction with bromine atoms, and the storing of electrons on Pd would increase the binding interaction. In the debromination process, methanol acts as both a hole scavenger and a hydrogen donor to provide active H atom species through the reaction of H + and photogenerated electrons on Pd nanoparticles. The initiation of BDE47 debromination on Pd nanoparticles required an induction period to enrich a critical amount of electrons for stretching the C-Br bond and its subsequent being attacked by active H atoms. The generated 2,2′-dibromodiphenyl ether (BDE4) would be further reduced to bromine-free products by hydro-debromination process or coupling reaction.
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CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Wei Wang,Jiaojiao Fang
Semiconductor-based heteronanostructures with wide light absorption and efficient electron-hole separation properties exhibit great potential for photocatalytic applications. Here we employ the mesoporous SiO 2 nanoparticles as the template to simultaneously exfoliate the nano-confined g-C 3 N 4 and deposit the CdS nanoparticles to form a series of core-shell SiCN@CdS heteronanostructures for photocatalytic H 2 production under the visible light irradiation. Based on the physicochemical characterizations, we have been able to discuss the compositions, structures, and properties of the core-shell photocatalysts . Benefiting from the optimized equilibrium state of a relative high specific surface area, light absorption, crystalline degree, and a homogeneous dispersion of the outer CdS nanoparticles, the SiCN@2CdS exhibits the highest photocatalytic activity and stability for H 2 production under the visible light irradiation. Results also suggest that the existence of the SiO 2 template is benefit to suppress the aggregation and improve the recyclability of the core-shell photocatalysts when they are applied in the aqueous phase. The present study suggests a new sight on the template-assisted designing and synthesizing high-reactive, low-cost, environmental-stable, and easy-recyclable photocatalysts by precisely controlling the microstructures.
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CARBON
·
2019
·
IF 7.466
Wei Miao,Ying Liu,Xiaoyan Chen,Yixin Zhao,Shun Mao
In recent years, design high catalytic graphitic carbon nitride (g–C 3 N 4 )–based catalysts has drawn broad attention in environmental remediation. In this work, a series of iron-doped g-C 3 N 4 compounds were synthesized through a simple bottom-up strategy. By controlled pyrolysis , iron-doped g-C 3 N 4 materials split from bulk structure into multi-layer structure with uniformly dispersed mesopores. The catalytic activities of layered iron-doped g-C 3 N 4 in Fenton-like and photo-Fenton-like processes were investigated. Due to the doped iron, unique layered structure, and mesopore feature, the catalysts present greatly enhanced performance in heterogeneous Fenton-like reactions. Moreover, the degradation parameters calculated by the pseudo-first-order kinetic model fitted well with the specific surface area of the catalyst, indicating that the catalytic activities rely heavily on the specific surface area of layered and porous g-C 3 N 4 . This study presents a facile and generic method to regulate C 3 N 4 morphology and structure for enhanced catalytic activity in Fenton-like reactions.
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2019
·
IF 6.393
Rui Liu,Bin Kong,Yun Chen,Xueping Liu,Shengli Mi
The helical structure is one of the most intriguing structures in nature; such an ingenious structure can be found from macromolecules to macroscopic areas, and the fabrication of helical structures has attracted research interest from mechanisms to applications. However, the fabrication of helical microfiber still remains a big challenge. In this study, a coaxial microfluidic device was made to continuously and controllably fabricate helical hydrogel microfibers with flexible shape by simply adjusting the flowrates. Various experimental conditions that can influence the diameter (d), pitch (p) and amplitude (A) of these formed coiled fibers were discussed. For the first time, the effects of G/M ratio of the alginates on the microfiber coiling phenomenon were examined. Additionally, magnetically responsive helical fibers were synthesized, and it is envisioned that hydrogel helical structure microfibers are highly versatile in different area, such as micro sensors, soft actuators and medical applications.
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APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Yao Chen,Fei Ding,Aung Khaing,Dong Yang,Zhongyi Jiang
Graphic carbon nitride (g-C 3 N 4 ) is a kind of promising organic semiconductor in visible light driven photocatalysis due to its metal free, high physicochemical stability and appealing electronic band structure . In this work, a porous hexagonal-prism g-C 3 N 4 (ACNH) photocatalyst was successfully synthesized via an acetic acid-assisted supramolecular assembly approach followed by calcination . The resulting ACNH materials have a corrugated and closely packed porous structure, which is composed of thin layers about 30 nm in thickness. The specific surface area of ACNH is as high as 67.7 m 2 g −1 , which is approximately 8-fold of bulk g-C 3 N 4 . Moreover, the porous structure induces the red shift of the absorption edge and facilitates the photo-induced charge separation of g-C 3 N 4 . Compared to bulk g-C 3 N 4 , the ACNH sample exhibits almost 13-fold improvement for the RhB degradation with the rate constant of 0.053 min −1 . This finding suggests that the acid-assisted supramolecular assembly may become a feasible method to synthesize g-C 3 N 4 -based photocatalysts with higher surface area and photocatalytic activity .
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Catalysis Science & Technology
·
2019
·Vol. 9
·期 10
·2571-2577
·
IF 5.726
Weiliang Qi,Siqi Liu,Fei Li,Heng Jiang,Zhixing Cheng,Shanlin Zhao,Minghui Yang
Transition metal nitrides have been recognized as excellent hydrogen evolution electrocatalysts and therefore are promising alternative co-catalysts for photocatalytic hydrogen production. Herein, iron nitride (Fe2N) nanoparticles have been prepared by using MOFs as sacrificial precursors. A novel g-C3N4–Fe2N nanostructure has been fabricated by an electrostatic self-assembly method at room temperature for photocatalytic H2 evolution. MOF-derived Fe2N nanoparticles as co-catalysts can promote photo-generated charge-carrier transportation/separation and decrease the overpotential of H2-evolution. Therefore, the optimal g-C3N4–Fe2N nanocomposite exhibits an obviously improved H2 evolution rate of 88.7 μmol g−1 h−1, which is almost 48 times higher than that of pure g-C3N4 nanosheets.
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Advanced Healthcare Materials
·
2019
·Vol. 8
·期 10
·1801534
·
IF 6.27
Chenyi Tang,Chao Liu,Yu Han,Qiaoqi Guo,Wei Ouyang,Huajun Feng,Meizhen Wang,Feng Xu
The widespread use of antibiotics has caused the rapid emergence of antibiotic-resistant bacterial strains and antibiotic resistance genes in the past few decades. Photocatalytic inactivation, a promising approach for the killing of pathogens, efficiently avoids the problems induced by antimicrobial drugs. However, traditional photocatalysts usually have some disadvantages, such as high costs of raw materials, ultraviolet ray excitation, and potential leaching of toxic metals. Here, a metal-free heterojunction photocatalyst, denoted as CQDs/g-C 3 N 4 , is synthesized through incorporating carbon quantum dots (CQDs) on graphitic carbon nitride (g-C 3 N 4 ), which significantly enhances photocatalytic inactivation of Staphylococcus aureus ( S. aureus ) compared with pure g-C 3 N 4 in vitro. CQDs/g-C 3 N 4 causes a rapid increase of intracellular reactive oxygen species levels and destruction of cell membranes under visible light, eventually leading to death of bacteria. The efficacy of CQDs/g-C 3 N 4 is further examined by a mouse cutaneous infection model of S. aureus . CQDs/g-C 3 N 4 markedly reduces the bacterial loads and prompts lesion recovery in mice, as compared with g-C 3 N 4 -treated group. In vivo and in vitro toxicity analyses show that the side effects of CQDs/g-C 3 N 4 are negligible. Considering the efficient photocatalytic inactivation and nontoxicity of CQDs/g-C 3 N 4 , this visible-light-driven photocatalyst paves a brand new avenue for the treatment of S. aureus infection.
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COMPOSITES SCIENCE AND TECHNOLOGY
·
2019
·
IF 6.309
Wangchang Li,Wei Huang,Yue Kang,Yu Gong,Yao Ying,Jing Yu,Jingwu Zheng,Liang Qiao,Shenglei Che
Modified cyanate resins (G-CE) and functionalized silica fibers (K-SFs) were obtained by introducing glycidyl polyhedral oligomeric silsesquioxane (G-POSS) and γ -aminopropyltriethoxy silane coupling agent (KH-550), respectively. G-CE and K-SFs were then used to fabricate K-SFs/G-CE wave-transparent composites. The activation energy of the G-CE blends decreased to 49.80 kJ/mol, which led to a decrease in the curing temperature from 274 °C to 254 °C. The contact angle of the functionalized silica fibers increased considerably to 107.4°; this modified the interfacial compatibility, which enhanced the mechanical properties . The K-SFs/G-CE composite had a maximum flexural strength of 548.1 MPa and flexural modulus of 19.3 GPa, which were increases of 86.7% and 48.5% compared to the corresponding values of SFs/CE composite (flexural strength of 293.5 MPa and flexural modulus of 13.0 GPa). In addition, the ε and tan δ of the K-SFs/G-CE composite decreased to 2.63 and 3.3 × 10 −3 , respectively, which were respective decreases of 6.5% and 23.0% compared with the corresponding values of SFs/CE composite ( ε of 2.76 and tan δ of 4.6 × 10 −3 ). Hence, the resulting K-SFs/G-CE composites are good candidate materials for high performance wave-transparent composites.
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高影响因子
ENVIRONMENTAL POLLUTION
·
2019
·
IF 5.714
Pan-Pan Jia,Tai Sun,Muhammad Junaid,Li Yang,Yan-Bo Ma,Zhi-Song Cui,Da-Peng Wei,Hao-Fei Shi,De-Sheng Pei
Graphene family nanomaterials (GFNs) have attracted significant attention due to their unique characteristics and applications in the fields of biomedicine and nanotechnology. However, previous studies highlighted the in vitro and in vivo toxicity of GFNs with size and oxidation state differences are still elusive. Therefore, we prepared graphene (G) and graphene oxide (GO) of three different sizes (S-small, M-medium, and L-large), and characterized them using multiple surface-sensitive analytical techniques. In vitro assays using HEK 293T cells revealed that the small and large sizes of G and GO significantly reduced the cell viability and increased DNA damage, accompanying with activated reactive oxygen species (ROS) generation and induced various expressions of associated critical genetic markers. Moreover, the bacterial assays highlighted that G and GO caused strong acute toxicity on Tox2 bacteria. Effects of G were higher than GO and showed size dependent effect: L > M > S, while the medium size of GO induced mild genetic toxicity on RecA bacteria. In vivo assays revealed that exposure to G and GO caused the developmental toxicity, induced ROS generation, and activated related pathways (specifically GO) in zebrafish. Taken together, G showed stronger ability to decrease the survival rate and induce the acute toxicity, while GO showed obvious toxicity in terms of DNA damages, ROS generation, and abnormal gene expressions. Our findings highlighted that G and GO differentially induced toxicity based on their varying physical characteristics, especially sizes and oxidation state, and exposure concentrations and sensitivity of the employed in vitro and in vivo models. In short, this study provided deep insights on the negative effects of GFNs exposure.
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JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 102
·期 11
·6517-6528
·
IF 3.094
Liu Pei,Yan Xu,Jiaqiang Liu,Junbiao Wu,Yide Han,Xia Zhang
Morphology modulation of photocatalyst has been demonstrated to be a crucial strategy for improving the catalytic performance in solar energy conversion system. Here we systematically investigated the influence of the solvent-dependent morphology evolution of Zn 2 GeO 4 phase on the photocatalytic efficiency of the as-prepared g-C 3 N 4 /Zn 2 GeO 4 composites. The morphologies of Zn 2 GeO 4 were rationally tuned from flower-like nanosheets to length-controllable nanorods, and microclusters assembled from microrods through regulating the solution polarity of different organic solvents. Accordingly, the Zn 2 GeO 4 sample prepared in ethylene glycol (EG) with long rod-like morphology and integrated with g-C 3 N 4 , abbreviated as g-C 3 N 4 /Zn 2 GeO 4 (1:1)-EG, exhibited the best visible-light absorption ability and the highest efficiency. The synergetic effect of the long rod-like Zn 2 GeO 4 phase with many exposed (110) crystalline facets and g-C 3 N 4 accelerates the separation and interface transportation of photoexcited charge carriers, as confirmed by photocurrent measurements. The MB degradation mechanism was also proposed to clarify the charge-transfer process and the improved photodegradation activity. This study offers an experimental basis for understanding the significance of morphology control on rational design of photocatalysts with improved performance.
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