ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Qian Wang,Zhi Yu,Junting Feng,Paolo Fornasiero,Yufei He,Dianqing Li
The production of biofuel 2,5-dimethylfuran (DMF) from an important biomass platform of 5-hydroxymethyl furfural (HMF) involves a complicated reaction pathway due to the competition of C═O hydrogenation and C–O hydrogenolysis; however, the dependence of formed intermediates and catalytic sites needs to be further identified. Herein, we constructed a highly efficient and selective Cu/ZnO-Al2O3 catalyst via reduction of a CuZnAl-layer double hydroxide (LDH) precursor, aimed for studying the effect of Cu0/Cu+ species on forming different intermediates and their synergetic promotional effect on HMF hydrodeoxygenation. As expected, the dependence of formation of different intermediates on the Cu+/Cu0 ratio was observed; notably, Cu/ZnO-Al2O3 with higher Cu+/Cu0 ratio finally gave 90.1% DMF selectivity at 100% HMF conversion, more selective than CuNi/Al2O3 (59.6%) and Cu/MgO-Al2O3 (75.8%) references. By a combined study of in situ IR experiments, the observed correlation between the reaction intermediates and the Cu0/Cu+ site suggests that Cu0 tends to adsorb the C═O bond as well as hydrogen molecule, while the Cu+ site is preferable to adsorb and activate the C–O bond. With the synergy of dual active sites, the Cu/ZnO-Al2O3 catalyst showed both high activity and selectivity to DMF. This work provides deep insight into the nature of active Cu species in multiple functional group biomass platform transformation.
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APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
He Wang,Jie Yu,Xiaohui Zhan,Lei Chen,Yanping Sun,Huixiang Shi
The development of high-efficiency heterostructure photocatalysts is an attractive strategy for aquatic pollutants degradation. Herein, a novel 2D/2D Z-scheme heterojunction between SnNb 2 O 6 nanosheets and flower-shaped ZnO nanosheets was designed and fabricated through a simple two-step hydrothermal method. As expected, the obtained composite photocatalyst exhibits outstanding photodegradation efficiencies for RhB and phenol. The optimal reaction rate constant over 20%-SnNb 2 O 6 /ZnO heterostructure in RhB degradation is almost 15.03 and 3.95 times higher than pristine SnNb 2 O 6 and ZnO, respectively. Such an improved photocatalytic activity is mainly ascribed to the broader optical absorption and facilitated charge separation, which can be proved by various analytical methods. This designed composite also displayed excellent stability in four-cycle experiments. Additionally, a possible direct Z-scheme electron migration mechanism under an internal electric field was proposed with the aid of reactive species trapping experiments. This work provides a feasible strategy to obtain high-performance photocatalysts and might inspire a new perspective in the design of other 2D/2D Z-scheme heterojunctions for environmental purification.
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APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Luwei Zhang,Haijuan Kong,Mengmeng Qiao,Xiaoma Ding,Muhuo Yu
Constructing the nondestructively chemical linking between organic phase and inorganic particles has become a hot direction for polymeric surface modification due to the rising demand of anti-ultraviolet (UV) products. Herein, aramid fiber (AF) with coordination of ZnO was developed by a facile supercritical CO 2 (Sc-CO 2 ) drying technique to improve its UV resistance and interfacial-adhesion. Through adjusting the Zn 2+ concentrations, the ZnO nanoparticles (NPs) with different decentralized system were synthesized and deposited to AF surface with stirring and the both were subsequently dried in Sc-CO 2 fluid for bonding. Results indicate that coordination between ZnO NPs and AF was established with the formation of C O Zn bond and the grafting yield of NPs was up to 34.23%. This ZnO-bonded fiber not only shows the greatly enhanced interfacial shear strength (IFSS) and UV resistance overcoming the two inherent defects of AF, but it was also endowed with higher mechanical and thermal performances than the original. For the AF-ZnO fibers in the optimum conditions, its IFSS was severely increased by 68.2%, compared to the pure AF, meanwhile the tensile strength retention after 216 h-UV irradiation is as high as 93.1%. Additionally, those fibers were obtained a better heat-resistant properties and mechanical properties, as the tensile strength and modulus, break elongation and energy were improved by 13.7%, 8.7%, 13.4% and 15.7%, respectively. Therefore, this research shows a fantastic success for nondestructively improving the interfacial-adhesion properties and UV resistance of AF.
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Sustainable Energy & Fuels
·
2020
·Vol. 4
·期 6
·2937-2949
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IF 5.503
Xin Hu,Xiaosong Hu,Qingxin Guan,Wei Li
Converting CO2 to CO via the reverse water gas shift (RWGS) reaction is an important route to reducing greenhouse gas emissions, and catalysts using copper and zinc as active components have been extensively studied for this reaction. Herein, the coordination and acid etching of trimesic acid (H3BTC) were used to assemble and regulate the Cu and ZnO components in the catalyst. First, Cu-HKUST-1 was synthesized by the self-assembly of H3BTC and copper ions, which limited the sintering and agglomeration of Cu nanoparticles in the subsequent carbonization and self-reduction process. Second, ZnO particles were etched by H3BTC to form the complex of H3BTC with Zn and to redisperse Zn species. Under the dual action of H3BTC, carbon-coated bimetal nanoparticles with a size of 2–6 nm were obtained on the fumed silica after pyrolysis at high temperature. The prepared Cu@C–ZnO/SiO2 catalyst can achieve 31.4% CO2 conversion and 99% CO selectivity in RWGS reaction in a fixed bed reactor at 400 °C and 3 MPa. Besides, we also found that the molar ratio of Cu/Zn, metal components, and the introduction order of H3BTC all affected the structure and composition of the catalyst, thus affecting the catalytic activity. This study provides an excellent strategy for the design and synthesis of catalysts containing copper and zinc components.
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Nanomaterials
·
2020
·Vol. 10
·期 4
·631
·
IF 4.324
Zhen Li,Libo Yu,Hao Wang,Huiwen Yang,Huan Ma
Light harvesting and electron recombination are essential factors that influence photovoltaic performance of quantum dots sensitized solar cells (QDSSCs). ZnO hollow microspheres (HMS) as architectures in QDSSCs are beneficial in improving light scattering, facilitating the enhancement of light harvesting efficiency. However, this advantage is greatly weakened by defects located at the surface of ZnO HMS. Therefore, we prepared a composite hollow microsphere structure consisting of ZnO HMS coated by TiO2layer that is obtained by immersing ZnO HMS architectures in TiCl4aqueous solution. This TiO2-passivated ZnO HMS architecture is designed to yield good light harvesting, reduced charge recombination, and longer electron lifetime. As a result, the power conversion efficiency (PCE) of QDSSC reaches to 3.16% with an optimal thickness of TiO2passivation layer, which is much higher when compared to 1.54% for QDSSC based on bare ZnO HMS.Keywords:TiO2passivation layer;ZnO hollow microspheres;quantum dots sensitized solar cells
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PubMed
高影响因子
Catalysts
·
2020
·Vol. 10
·期 5
·533
·
IF 3.52
Jinjun Wen,Chunlei Huang,Yuhai Sun,Long Liang,Yudong Zhang,Yujun Zhang,Mingli Fu,Junliang Wu,Limin Chen,Daiqi Ye
CO2hydrogenation to methanol is one of the main and valuable catalytic reactions applied on Cu/ZnO-based catalysts; the interface formed through Zn migration from ZnO support to the surface of Cu nanoparticle (ZnOx-Cu NP-ZnO) has been reported to account for methanol synthesis from CO2hydrogenation. However, the accompanied reverse water gas shift (RWGS) reaction significantly decreases methanol selectivity and deactivates catalysts soon. Inhibition of RWGS is thus of great importance to afford high yield of methanol. The clear understanding of the reactivity of RWGS reaction on both the direct contact Cu-ZnO interface and ZnOx-Cu NP-ZnO interface is essential to reveal the low methanol selectivity in CO2hydrogenation to methanol and look for efficient catalysts for RWGS reaction. Cu doped plate ZnO (ZnO:XCu) model catalysts were prepared through a hydrothermal method to simulate direct contact Cu-ZnO interface and plate ZnO supported 1 wt % Cu (1Cu/ZnO) catalyst was prepared by wet impregnation for comparison in RWGS reaction. Electron paramagnetic resonance (EPR), XRD, SEM, Raman, hydrogen temperature-programmed reduction (H2-TPR) and CO2temperature-programmed desorption (CO2-TPD) were employed to characterize these catalysts. The characterization results confirmed that Cu incorporated into ZnO lattice and finally formed direct contact Cu-ZnO interface after H2reduction. The catalytic performance revealed that direct contact Cu-ZnO interface displays inferior RWGS reaction reactivity at reaction temperature lower than 500 °C, compared with the ZnOx-Cu NP-ZnO interface; however, it is more stable at reaction temperature higher than 500 °C, enables ZnO:XCu model catalysts superior catalytic activity to that of 1Cu/ZnO. This finding will facilitate the designing of robust and efficient catalysts for both CO2hydrogenation to methanol and RWGS reactions.Keywords:reverse water–gas shift reaction;CO2hydrogenation to methanol;Cu doping;direct contact Cu-ZnO interface;ZnOx-Cu NP-ZnO interface
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ACS Nano
·
2020
·
IF 14.588
Shijun Wang,Diansen Li,Yue Zhou,Lei Jiang
The increasing demand for wearable electronics and the intensification of electromagnetic pollution have boosted the exploration of high-performance flexible microwave absorption (MA) materials. Herein, the hierarchical Ti3C2Tx MXene/Ni chain/ZnO array hybrid nanostructures are rationally constructed on cotton fabric for acquiring enhanced MA performance and durable self-cleaning ability. Based on the high dielectric loss capacity of MXenes and ZnO arrays, by controlling dip-coating numbers of Ni chains, the magnetic loss can be manipulated to modulate the impedance matching, reflection loss (RL), and effective absorption bandwidth (EAB, the bandwidth of RL < −10 dB). The minimum RL value of the designed fabric can reach −35.1 dB at 8.3 GHz with a thickness of 2.8 mm, and its EAB can cover the whole X-band with only a 2.2 mm thickness. In addition, the designed fabric also exhibits superior liquid repellency and durable self-cleaning ability due to the combination of the hybrid nanostructures and a superhydrophobic coating. This work provides an insight for rational design of textile-based MA materials, showing potential applications in flexible and wearable functional electronics.
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高影响因子
NANOTECHNOLOGY
·
2021
·Vol. 32
·期 37
·375001
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IF 3.874
Yue Yang,Tong Zou,Rongjun Zhao,Yulin Kong,Linfeng Su,Dian Ma,Xuechun Xiao,Yude Wang
In this work, an efficient and stable fluorescent probe for Al3+ was established. The fluorescent probe based on the fluorescence 'turn-on' mode of zinc sulfide crystal composite zinc oxide quantum dots (ZnS/ZnO QDs). The ZnS/ZnO QDs were synthesized via two-step method using L-Cysteine (L-Cys) as a sulfur source and stabilizer. In the synthesis of ZnS/ZnO QDs, the fluorescence of zinc oxide quantum dots (ZnO QDs) decreased and its stability increased in aqueous solution after the addition of L-Cys. In addition, the as-synthesized ZnS/ZnO QDs shows fluorescent enhancement to Al3+. The ZnS/ZnO QDs based fluorescence 'turn-on' probe presented wide linear ranges (1 nM–8 μM and 8–100 μM). The availability of as-established sensing probe was also estimated by real water sample tests. Furthermore, the fluorescent enhancing mechanism was carried out by recording the fluorescent lifetime of samples, which might be related to the QDs dispersion and charge transfer weaken.
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高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Ben Chen,Jin Zhang,Jing Yu,Rui wang,Beibei He,Jun Jin,Huanwen Wang,Yansheng Gong
Poor visible light utilization and charge separation efficiency of TiO 2 restrict its extensive application in the photocatalytic field. Herein, a specific Z-scheme TiO 2-x /Cu/ZnO heterojunction was successfully constructed by atomic layer deposition (ALD) technique and spray pyrolysis technology. Benefited from the surface plasmon resonance (SPR) effect of Cu and Z-scheme heterojunction, the visible light absorption capacity was greatly enhanced. Meanwhile, ZnO nanolayer coating, prepared by ALD technique, protects Cu element to hinder its oxidation, thus enhancing the separation efficiency of photogenerated carriers. Therefore, the photocatalytic hydrogen production performance was significant improved, exhibiting a maximum value of 342.0 µmol·g −1 ·h −1 for the optimal B-T-0.1C-10Z (black TiO 2 /0.1Cu/10 nm ZnO) sample without any noble-metal cocatalyst, which is higher than pure TiO 2 (310.7 µmol·g −1 ·h −1 , with 3 wt% Pt) synthesized by spray pyrolysis method under equal conditions. In addition, a possible mechanism for the enhanced performance was briefly discussed based on the experimental results.
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JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
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2021
·
IF 8.067
Yiqian Lv,Yueqing Zheng,Honglin Zhu,Yinghao Wu
As a semiconductor material with a 2D-laminate structure, g-C 3 N 4 (bandwidth 2.7 eV) has a similar structure and excellent performance to graphene. However, high surface energy and photogenerated e–h recombination of g-C 3 N 4 seriously hinder its application in the field of marine anticorrosion and antifouling. To solve these problems, we synthesized the g-C 3 N 4 nanosheets decorated with ZnO nanoring via chemical etching technology. Whether the NR ZnO-CNNs have surface protection performance among the pure EP on the corrosion protection for metal substrate were investigated. The antifouling properties NR ZnO-CNNs hybrid were also estimated through photocatalytic bacterial and algae resistance tests. Combined with the electrochemical results, it was found that the impedance modulus of NR ZnO-CNNs/EP within 45 days showed two orders of magnitude higher than that of pure EP in the 3.5 wt% NaCl solution. Besides, Local electrochemical impedance spectroscopy (LEIS) further explored the anticorrosion behavior of NR ZnO-CNNs/EP coating, which indicated that the NR ZnO-CNNs/EP coating with a scratch maintained an excellent corrosion resistance between 0–24 h. Under the visible light conditions, the lifetime of photogenerated e–h was prolonged due to the formation of NR ZnO-CNNs heterojunction structure, it was observed that the antibacterial rate against Bacillus subtilis reached 100% within 8 h. An Antialgae test was performed on chlorella seawater solution, which indicated that 5 mg/mL of NR ZnO-CNNs hybrid could make chlorella sharply reduce within 4 days. Simultaneously, the corrosion protection and photocatalytic antifouling mechanisms of NR ZnO-CNNs were proposed, thus it provided a broader platform for the design of versatile marine protection materials.
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CRYSTENGCOMM
·
2019
·Vol. 21
·期 42
·6414-6422
·
IF 3.382
Rui Zhang,Wanqing Song,Mingjing Wang,Huiming Ji
Metal–organic framework (MOF) materials with controlled microstructures have become popular in the last few decades. In this study, Zn-MOF precursors with diverse crystallinity and particle size (20–800 nm) were synthesized using an accelerating or retarding nucleation process by introducing various secondary ligands, which were employed as modulators in the coordination and ligand exchange equilibria according to their different acidity coefficients. Thus, the pore size of MOF-derived ZnO clusters was different, resulting in diverse gas sensing properties. Moreover, large precursor-derived ZnO-(2 and 3) assemblies with the micropore sizes of 1 nm and 0.75 nm showed size-selective sensing and better performance, which exhibited a higher and fast response (4 s) to butanone and n-butanol with the lengths of 0.664 nm and 0.499 nm, respectively, and a low limit of detection (0.1 ppm). This simple method of controlling the nucleation of MOFs and the pore size of ZnO assemblies paved a new way towards the design of the microstructure of MOF-based functional materials.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2019
·
IF 3.131
Chuanbo Hu,Ying Li,Tingzhen Li,Yongquan Qing,Jianting Tang,Huawei Yin,Lei Hu,Lei Zhang,Yongsheng Xie,Kangning Ren
In this investigation, a comparative study on the anticorrosion properties of poly( N -methylaniline) (PNMA) coating, as well as PNMA-ZnO and PNMA/SiC-ZnO bilayer coatings, was carried out. The polymeric materials (PNMA and PNMA/SiC composite) were synthesized by emulsion polymerization method. The structures of the obtained polymeric materials were determined by different optic techniques, and the electrochemical activity and stability were examined by cyclic voltammetry . Subsequently, PNMA was spread on the surfaces of carbon steel and ZnO coating by chemical deposition method, and PNMA/SiC was spread on the surface of ZnO coating, which led to obtaining PNMA coating, PNMA-ZnO and PNMA/SiC-ZnO bilayer coatings. The structures of ZnO coating were characterized by X-ray diffraction and energy dispersive spectrometer, and the surface morphologies of all the coatings were also studied by field emission scanning electron microscopy . The anticorrosion properties of all the coatings were evaluated by electrochemical corrosion and accelerated immersion in the presence of a 3.5% NaCl solution. The results demonstrated that the polymeric materials-ZnO bilayer coatings had excellent corrosion protection ability, and in specific, for the carbon steel protected by PNMA/SiC-ZnO bilayer coatings it was higher than PNMA-ZnO bilayer coatings, with a corrosion rate of 0.004 mm/year and the protection efficiency was up to 97.43%. Overall, this study proves that the rough ZnO coating is beneficial to the embedding and pinning of polymeric materials, and the formed PNMA/SiC-ZnO bilayer coatings possess a strong adsorption ability and wide coverage area to the carbon steel substrate, which facilitates the external PNMA/SiC film to develop its unique barrier and passivation effects to prevent carbon steel from being corroded. The protection mechanism conferred by polymeric materials-ZnO bilayer coatings has also been discussed.
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