Frontiers in Bioengineering and Biotechnology
·
2022
·
IF 6.064
Ni Yun,Lv Zhixiang,Wang Zhou,Kang Shouyu,He Dawei,Liu Ruijiang
Magnetic α-Fe2O3/Fe3O4 heterostructure nanosheets were fabricated via hydrothermal calcination. The activity of penicillin G acylase (PGA), which was covalently immobilized onto silica-decorated heterostructure nanosheets, achieved the highest activity of 387.03 IU/g after 18 h of incubation with 0.1 ml of PGA. In contrast, the activity of free PGA reached the highest level when the temperature was 45°C with a pH of 8.0. However, the activity of free PGA changed more dramatically than immobilized PGA as the relative conditions changed. Moreover, the Michaelis–Menten constant (Km) and reusability of immobilized PGA were also explored. The results showed that free PGA Km and maximum rate (Vmax) were 0.0274 M and 1.167 μl/min, respectively. Km and Vmax values of immobilized PGA were 0.1082 M and 1.294 μl/min, respectively. After 12 cycles of repetitive use, immobilized PGA remained approximately 66% of its initial activity, indicating that the PGA immobilized onto the heterostructure nanosheets showed better stability and reusability than free PGA.
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高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2023
·
IF 4.5
Hao Liu,Runhe He,Yongbing Li,Yanmei Jin,Haihui Liu,Xingxiang Zhang
Sulfurized polyacrylonitrile (SPAN) is a promising cathode material for the commercialization of lithium-sulfur batteries with extremely stable cycling performance. However, its inherent low sulfur content and poor electrical conductivity severely impairs its electrochemical performance. In this work, we construct a sulfur cathode in the form of a unique bamboo-shaped structured nanofiber, using SPAN as the bamboo stalk and reduced graphene oxide (rGO) as the bamboo joint, thus ensuring that the SPAN has excellent electronic conductivity. Polyacrylonitrile grafted with rGO (PAN -g- rGO) is an effective composite of ultra-high molecular weight PAN (UHMW PAN) and rGO at the molecular level. The UHMW PAN precursor can provide high sulfur loading, and the bamboo joint-like rGO can offer short-range accelerated electron transfer, thus effectively enhancing the electrochemical performance of the battery. Sulfurized PAN -g- rGO fiber (SFPAN -g- rGO) with a sulfur content of approximately 53 wt% is fabricated using PAN -g- rGO with a molecular weight of 3.6 × 10 5 Da as the precursor. The battery has a high reversible specific capacity (1463 mAh g −1 at 0.2C), excellent C-rate performance (1239 mAh g −1 at 2C), and good cycling stability (guaranteed over 800 cycles). In addition, the electrode offers a high reversible specific capacity of 1383 mAh g −1 at 0.1C and 1280 mAh g −1 at 0.2C when tested under a lean electrolyte (E/S: 10 μL mg −1 ) and high mass loading (4.8 mg cm −2 ), thus illustrating its good development potential.
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Analytical Methods
·
2021
·Vol. 13
·期 48
·5830-5837
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IF 2.896
Shouhui Chen,Jingguo Yu,Zhen Chen,Zhenzhong Huang,Yonghai Song
The presence of Cd2+, Pb2+, Cu2+ and Hg2+ in drinking-water can be harmful to human health, even if their concentration is fairly low. Hence, it is significant to detect these heavy metal ions in sewage to evaluate the quality of water. Herein, amino-functionalized metal–organic frameworks (NH2-MIL-88(Fe)) embedded with graphitic carbon nitride (g-C3N4) nanosheets and acid-functionalized carbon nanotubes were prepared via a one-pot synthesis. The composite can be directly modified on the surface of glass carbon electrodes without the assistance of Nafion or other binders. The modified glass carbon electrodes can be used to simultaneously detect Cd2+, Pb2+, Cu2+ and Hg2+ in water via square wave stripping voltammetry. The doping of g-C3N4 in the composite, rich in N-containing functional groups, participates in the adsorption of metal ions on the surface of the electrodes. The porous composite provides accommodation room for metals generated by electro-reduction. The detection limit for Cd2+, Pb2+, Cu2+ and Hg2+ is 39.6 nM, 7.6 nM, 11.9 nM, and 9.6 nM, respectively. And the sensitivity for Cd2+, Pb2+, Cu2+ and Hg2+ is 0.0789 mA μM−1 cm−2, 0.4122 mA μM−1 cm−2, 0.2616 mA μM−1 cm−2, and 0.3251 mA μM−1 cm−2, respectively. This work not only enriches the functional design of Fe-MOF materials, but also develops a method for the determination of metal ions using the adsorption sites in g-C3N4.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 47
·22123-22132
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IF 3.591
Jing Liu,Dianming Li,Xiaofeng Liu,Jie Zhou,Hong Zhao,Nü Wang,Zhimin Cui,Jie Bai,Yong Zhao
Hydrogen evolution and dye degradation catalyzed by environmentally benign and inexpensive photocatalyst in aqueous solution is regarded as a promising avenue to effectively address the global energy and environmental crisis. It is difficult for traditional photocatalysts to perform efficient light harvesting, with conducive recycling and promoted charge separation and transport, which limit practical applications in photocatalytic conversion. In this study, a facile template-assisted coaxial electrospinning approach was explored to successfully build close contacted heterojunctions within the interface of g-C3N4 nanosheets and hollow porous TiO2 nanofibers, which significantly increased the separation efficiency of photo-induced electron–hole pairs in the visible-light region. A hollow and porous structure with abundant surface-active sites assisted in inducing multiple light reflection for more efficient light harvesting. Moreover, one dimensional TiO2/g-C3N4 composite nanofibers with a large length-to-diameter ratio would be more attractive for recovery. At the optimal g-C3N4 loading, hollow porous TiO2/g-C3N4-50% nanofibers exhibited the highest rate of hydrogen evolution and RhB degradation. The enhanced photocatalytic performance of hollow porous TiO2/g-C3N4 composite photocatalysts was mainly attributed to the synergistic effect of the hollow porous architecture and heterojunction. This work might make a significant contribution to insight into preparing hollow structure heterogenous nanofiber photocatalysts with improved activities in hydrogen generation and pollutant degradation.
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APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Jianmei Pan,Yahai Zhang,Yi Guan,Yingnan Yan,Hua Tang,Xianglong Liu,Mengdi Wang,Xiangxin Wei
The development of hydrogen (H 2 ) production photocatalyst with low cost, non-precious metal and high-activity for commercial application is a long-term target and challenge. In this work, novel silicon carbide (SiC) nanofibers/graphitic carbon nitride (g-C 3 N 4 ) nanosheets (SiC/CNNS) decorated via multipurpose nickel (Ni) nanoparticles were prepared by an easy heat treatment followed by hydrothermal method. The tight Ni interface layers as cocatalyst and electron transfer mediator can significantly enhance the H 2 production property over SiC/CNNS nanoheterojunctions under light-emitting diode (LED) illumination. The optimal Ni/SiC/CNNS with a mass fraction of 10% Ni loading shows the most superior H 2 -generation rate of 6183 μmol g −1 h −1 , which is approximately 53, 3 and 227 times compared to CNNS, 10 %Ni/CNNS and SiC/CNNS, respectively. The metallic Ni nanoparticles play the leading and multifunctional roles in improving photocatalytic activity, including collecting the photo-generated electrons efficiently, transferring and separating the charge carriers rapidly, facilitating the H 2 -production kinetics and decreasing the overpotentials of surface reactions for H 2 -production. It is highly expected that the multipurpose and non-precious metal cocatalyst to form tight interface layers can supply a simple and universal strategy to design high-efficiency cocatalyst-semiconductor–semiconductor photocatalysts for H 2 production.
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Nanomaterials
·
2021
·Vol. 11
·期 12
·3341
·
IF 5.076
Yuan Guo,Wanqing Liu,Wei Duan,Siyu Wang,Liqun Jia,Guoqing Zhang,Baolin Zhu,Weiping Huang,Shoumin Zhang
Photocatalytic water splitting for hydrogen generation is a significant pathway for sustainable energy conversion and production. The photocatalysts with a Z-scheme water splitting charge transfer pathway is superior due to the good separation and migration ability of photoexcited charge carriers. Herein, Co3O4/g-C3N4photocatalysts with Z-scheme charge transfer pathway were successfully constructed by an electrostatic interaction-annealing method. The as-prepared Co3O4/g-C3N4ultra-thin nanosheets were tested and analyzed by XRD, EA, ICP, SEM, TEM, AFM, XPS, UV-Vis DRS, PL and photoelectrochemical measurements. Moreover, the influences of fabrication parameters on performance of Co3O4/g-C3N4catalysts were investigated, and 0.5% Co3O4/g-C3N4exhibited the optimal activity. Based on the characterization and catalytic performance, the Z-scheme charge transfer pathway of Co3O4/g-C3N4was established and put forward. To further improve the catalytic performance of Co3O4/g-C3N4, 0.5% Pt was added as a co-catalyst. The obtained Pt/0.5% Co3O4/g-C3N4was recyclable and remained the original catalytic water splitting performance within 20 h. The modification of Co3O4and Pt improved the separation and migration of e−and h+, and induced the increased hydrogen evolution rate of g-C3N4.Keywords:Co3O4/g-C3N4ultra-thin nanosheets;Z-scheme charge transfer pathway;photocatalytic;water splitting;H2evolution
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Nano Research
·
2021
·Vol. 15
·期 4
·2928-2934
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IF 8.897
Xiao Xudong,Lin Siying,Zhang Liping,Meng Huiyuan,Zhou Jing,Li Qi,Liu Jianan,Qiao Panzhe,Jiang Baojiang,Fu Honggang
The formation of chemical bonds between metal ions and their supports is an effective strategy to achieve good catalytic activity. However, both the synthesis of active metal species on a support and control of their coordination environment are still challenging. Here, we show the use of an organic compound to produce tubular carbon nitride (TCN) as a support for Pd nanoparticles (NPs), creating a composite material (NP-Pd-TCN). It was found that Pd ions preferentially bind with the electron-rich N atoms of TCN, leading to strong metal-support interactions that benefit charge transfer from g-C 3 N 4 to Pd. X-ray absorption spectroscopy further revealed that the metal-support interactions resulted in the formation of Pd-N bonds, which are responsible for the improvement in the charge dynamics as evidenced by the results from various techniques including photoluminescence (PL) spectroscopy, photocurrent measurements, and electrochemical impedance spectroscopy (EIS). Owing to the good dynamical properties, NP-Pd-TCN was used for photocatalytic hydrogen evolution under visible-light irradiation ( λ > 420 nm) and an excellent evolution rate of ∼ 381 µmol·h −1 (0.02 g of the photocatalyst) was attained. This work aims to promote a strategy to synthesize efficient photocatalysts for hydrogen production by controllably introducing metal nanoparticles on a support and in the meantime forming chemical bonds to achieve intimate metal-support contact.
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Catalysis Science & Technology
·
2021
·Vol. 11
·期 24
·7963-7972
·
IF 6.119
Anyu Liu,Jianqiang Hu,Jiale He,Xinyue Huang,Na Hu,Yuqin Li,Qingling Huang,Shien Guo,Xin Liu,Zhen Yang,Yong Zhou,Zhigang Zou
O-doped g-C3N4/In2S3 hierarchical heterostructures with a direct Z-scheme mechanism were devised and constructed simply via loading In2S3 nanoflakes on the surface of O-doped g-C3N4 (OCN) hierarchical structures, in situ, employing pre-obtained OCN (prepared by condensation of oxalic acid and urea) and indium(III) dimethyldithiocarbamate (In(dedc)3) as precursors. Analyses of the energy band structure, density functional theory (DFT) computations and DMPO-ESR spin-trapping experiments demonstrate that the formation of a perfect heterointerface with a staggered alignment of band edges between OCN and In2S3 (IS), owing to their close contact, enables photoexcited carriers to migrate via a Z-scheme route, which can maintain the higher reduction and oxidation capability of electrons and holes, respectively. Furthermore, the Z-scheme OCN/IS heterostructures efficaciously facilitate the separation of photogenerated electrons and holes, as demonstrated using PL spectra, transient photocurrent densities and electrochemical impedance spectra (EIS). These lead to the enhanced photocatalytic activity towards reducing Cr(VI) into Cr(III). Besides, the integration of OCN with IS can enhance the responsiveness to visible light based on the results of UV-vis DRS, thereby inducing the formation of more electrons and holes,and also contributing to the improvement of the photocatalytic activity for Cr(VI) reduction. In consequence, all the pre-prepared OCN/IS hybrids possess markedly improved photocatalytic activities for Cr(VI) reduction, relative to pure OCN and pristine IS under visible light (λ > 420 nm) illumination. With the increase in the In(dedc)3 to OCN mass ratio (R), the photocatalytic activities of these OCN/IS hybrids increase first and then decrease. The sample with an optimum R of 0.9 (OCN/IS-0.9) can remove nearly 100% of Cr(VI) after 40 min of illumination, being superior to most of g-C3N4-based and IS-based photocatalysts. Its reaction rate constant for Cr(VI) photoreduction (0.08947 min−1) is 56.7 fold and 8.8 fold higher than that of pure OCN (0.00155 min−1) and pristine IS (0.00913 min−1), respectively. This work affords a deep understanding on designing preeminent Z-scheme photocatalysts towards the degradation of Cr(VI) under visible-light irradiation.
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JOURNAL OF HAZARDOUS MATERIALS
·
2023
·
IF 13.6
Yin Tang,Wen Cui,Songxia Wang,Fan Dong
Though photocatalytic purification of NO has been widely studied, how to avoid secondary pollution during gas-solid reaction is still a challenge, especially in inhibiting the formation of toxic intermediates (NO 2 ) and avoiding the blow away of powdery photocatalyst. Herein, we proposed a one-step solvothermal method to prepare melamine sponge (MS) supported and functionalized g-C 3 N 4 (CN), which simultaneously realizes the inhibition of NO 2 formation and catalyst loss. Sodium hydroxide , which plays a dual role, has been introduced during the preparation of supported photocatalyst. Specifically, sodium atom, as the modifier of performance, could facilitate the randomly distributed charge of pristine CN to be converged, which accelerates the adsorption/activation of reactants for efficient and deep NO oxidation . Hydroxyl group, as the binder between CN and MS, induces the interaction by forming hydrogen bonds , which contributes to the firm immobilization of powdery photocatalyst. The supported sample exhibits outstanding NO removal rate (58.90%) and extremely low NO 2 generation rate (1.41%), and the mass loss rate of photocatalyst before and after reaction is less than 1%. The promotion mechanism of performance also has been elaborated. This work takes environmental risks as a prerequisite to propose a feasible strategy for perfecting the practical application of photocatalytic technology .
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高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2023
·
IF 9.5
Fan Yang,Su Li,Hongyan Qi,Weibo Sun,Jinbao Li,Mei Zhang,Zheng Chen,Jinhui Pang,Zhenhua Jiang
Although poly (ether ether ketone) (PEEK) exhibits excellent solvent resistance , it could not be prepared directly by non-solvent induced phase separation (NIPS) method due to its poor solubility. Herein, PEEK porous membranes were successfully fabricated by combining NIPS and acid hydrolysis. The superhydrophilic thermo-responsive poly (N-isopropylacrylamide) (PNIPAm) polymer was in-situ grafted on the PEEK membrane surface via the UV grafting polymerization and improved the membrane interface hydrophilicity, making the membrane water contact angle changed from 89.5° to 0° at 25 °C. After heating the membrane surface to 40 °C, the membrane exhibited hydrophobicity (100°), realizing the thermo-responsiveness via switching the temperature. Furthermore, due to the transferred membrane wettability at different temperatures, PEEK-g-PNIPAm could separate different types of oil-bearing systems with high rejection above 99.0 %. What’s more, the PNIPAm layer also enhanced the membrane anti-fouling capacity. Benefiting from the extraordinary solvent resistance of the PEEK matrix, PEEK-g-PNIPAm maintains its intact morphology after 6 h immersion in various organic solvents , addressing the commonly reported problem of polymer membranes having certain solubility in solvents. The PEEK-based membranes with excellent solvent resistance could be useful in the oil-bearing separation.
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高影响因子
LANGMUIR
·
2023
·
IF 3.9
Anran Li,Zhenyu Zhang,Chengqi Feng,Ting Zhang,Fei Liu,Haining Na,Jin Zhu
Graphite carbon nitride (g-C3N4) with a suitable structure and strong amine activity is designed and prepared to serve as a hydrogen bond donor for the microfibrilization of corncob cellulose to form a cellulose microfiber (CMF) bundle. Simultaneously, well-dispersed nanosized g-C3N4 is loaded into the bundle to form a photocatalyst for efficient photodegradation of rhodamine B (Rh B) in water. Under the optimal preparation conditions at 165 °C, 10 min, and 0.08 mol/L H2SO4, the yield of g-C3N4-functionalized cellulose microfibers (CMF-g-C3N4) reaches to the highest over 70%. The catalytic rate of CMF-g-C3N4 is 3.3 times larger than that of pure g-C3N4. The degradation rate of Rh B is maintained at over 90% in 10 cycles of photocatalytic degradation. The obtained CMF-g-C3N4 also has good thermal stability and mechanical properties. This research suggests a particularly simple way to transform cellulose into a highly efficient photocatalyst for water treatment.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 48
·22050-22062
·
IF 3.3
Hui-Qin Zheng,Wen-Li Zhang,Min-Cai Yin,Yao-Ting Fan
In the present work, a ternary composite MoS2/soluble g-C3N4/CdS was synthesized using a facile one-pot hydrothermal reaction and conventional reflux reaction method. The composition, morphology, and properties of the ternary composite were characterized. The photocatalytic performance of the ternary composite was evaluated for hydrogen generation under LED lamp irradiation (450 nm < λ < 465 nm) with lactic acid (LA) used as a sacrificial reagent. The results demonstrated that the maximum hydrogen production reached 4869.6 μmol under the optimal hydrogen production conditions, including a composition of 20% soluble g-C3N4, 9% MoS2, a solution pH of 1, and an irradiation time of 6 hours. The corresponding hydrogen production rate for the ternary composite was calculated to be 8116 μmol g−1 h−1. Furthermore, a possible electron transfer mechanism of the ternary composite system was briefly explored. The interaction and synergistic effects between MoS2, soluble g-C3N4, and CdS in the ternary composite likely facilitate efficient electron transfer, resulting in enhanced photocatalytic activity for hydrogen production. Mechanistic research showed that the electron transfer pathway represented either a double or single type II heterojunction photocatalytic system.
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