CHINESE JOURNAL OF CATALYSIS
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2024
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IF 15.7
Xuyu Luo,Ying Wang,Guang Yang,Lu Liu,Shiying Guo,Yi Cui,Xiaoyong Xu
ABSTRACT Alkaline water electrolysis allows the adoption of non-precious metal catalysts , but increases the challenge of cathodic hydrogen evolution reaction (HER) with the proton-deficient environment. Here we report an “all-in-one” design by atomic-level tailoring on molybdenum sulfide (MoS 2 ) basal planes with synergistic active centers to trigger water dissociation for proton supply and meanwhile improve proton adsorption for hydrogen evolution. The resultant Co/O-codoped MoS 2 (Co-O@MoS 2 ) catalyst shows superb alkaline HER activity with a small Tafel slope of 42 mV dec –1 and an overpotential as low as 81 mV at 100 mA cm –2 , and considerable stability over 300 h even at industrial-grade high current density of 600 mA cm –2 , which are among the best records for precious-metal-free HER catalysts in alkaline media. The markedly enhanced alkaline HER performance is attributed to the synergistic effect from atomically constructed O-Co-S 2 motifs with local electronic interactions, in which Co sites promote the premier water dissociation, and S sites facilitate proton transition to generate hydrogen, respectively. This work presents an atomic-scale structural modification to create synergistic active sites for alkaline HER and provides insights into the atomic activation engineering towards advanced catalysts.
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高影响因子
Smart Materials and Structures
·
2015
·Vol. 24
·期 6
·065026
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IF 2.502
Qingsong He,Min Yu,Xu Yang,Kwang Jin Kim,Zhendong Dai
A newly developed ionic electro-active actuator composed of an ionic electrolyte layer sandwiched between two graphene film layers was investigated. Scanning electronic microscopy observation and x-ray diffraction analysis showed that the graphene sheets in the film stacked in a nearly face-to-face fashion but did not restack back to graphite, and the resulting graphene film with low sheet resistance (10 Ω sq−1) adheres well to the electrolyte membrane. Contact angle measurement showed the surface energy (37.98 mJ m−2) of the ionic electrolyte polymer is 2.67 times higher than that (14.2 mJ m−2) of the Nafion membrane, contributing to the good adhesion between the graphene film electrode and the electrolyte membrane. An electric double-layer is formed at the interface between the graphene film electrode and the ionic electrolyte membrane under the input potential, resulting in a higher capacitance of 27.6 mF cm−2. We report that this ionic actuator exhibits adequate bending strain, ranging from 0.032 to 0.1% (305 to 945 μm) as functions of voltage.
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Chinese Physics B
·
2015
·Vol. 24
·期 11
·118501
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IF 1.603
Chang-Bai Liu,Ying He,Sheng-Lei Wang
In this work, pure α-Fe2O3 and Er2O3-Fe2O3 nanotubes were synthesized by a simple single-capillary electrospinning technology followed by calcination treatment. The morphologies and crystal structures of the as-prepared samples were characterized by scanning electron microscopy and x-ray diffraction, respectively. The gas-sensing properties of the as-prepared samples have been researched, and the result shows that the Er2O3-Fe2O3 nanotubes exhibit much better sensitivity to ethanol. The response value of Er2O3-Fe2O3 nanotubes to 10 ppm ethanol is 21 at the operating temperature 240°, which is 14 times larger than that of pure α-Fe2O3 nanotubes (response value is 1.5). The ethanol sensing properties of α-Fe2O3 nanotubes are remarkably enhanced by doping Er, and the lowest detection limit of Er2O3-Fe2O3 nanotubes is 300 ppb, to which the response value is about 2. The response and recovery times are about 4 s and 70 s to 10 ppm ethanol, respectively. In addition, the Er2O3-Fe2O3 nanotubes possess good selectivity and long-term stability.
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Smart Materials and Structures
·
2015
·Vol. 24
·期 7
·075001
·
IF 2.502
Qingsong He,Linlin Song,Min Yu,ZhenDong Dai
We develop an ionic polymer metal-carbon nanotube composite (IPMCC) actuator composed of a multiwalled carbon nanotube (MWCNT)/Nafion membrane sandwiched between two hybrid electrodes, composed of palladium, platinum and MWCNTs. The surface morphology and cross-sectional structure of the metal-carbon nanotube hybrid electrode were observed using scanning electron microscopy (SEM). SEM investigation indicated that the MWCNT layer can adhere very well with the platinum–palladium metal electrode, fill the cracks in the metal surface, and prevent the oxidation of nanoscale platinum particles. These observations show that the surface resistance of the total electrode is retained and the stability of electrode property is maintained. The displacement, blocking force and nonlinear current versus voltage (V–I) characteristics were measured. Compared with an ionic polymer metal composite (IPMC), the IPMCC shows a more stable displacement and blocking force under 1, 1.2 and 2 V at 0.1 Hz, and 2.34–3.29 times higher effective air-operating time under 3 V at 0.1 Hz. It can be observed from the V–I characteristics that the change in shape becomes significant at amplitudes higher than 1.2 V. An equivalent circuit is used to model the nonlinear behavior of the IPMCC, in which the leakage current was taken into account and analyzed. The values of the components in the circuit are estimated and electrical behavior is simulated by using the Pspice software. Compared with the model with no consideration of the leakage current, the simulations obtained by the model considering leakage current showed better agreement with the experimental results. The impressive leakage current (20 mA), which is successfully simulated by the proposed model with the nonlinear circuit, is shown to play an important role in the total current.
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CHINESE JOURNAL OF CATALYSIS
·
2024
·
IF 15.7
Jielin Huang,Jie Wang,Haonan Duan,Songsong Chen,Junping Zhang,Li Dong,Xiangping Zhang
Catalysts for CO 2 value-added conversion have been extensively explored, but there is still a lack of systematic design for catalysts that achieve efficient CO 2 conversion under mild conditions. Herein, we explored a mesoporous CeO 2 single-crystal formed with the regulation of ionic liquids, which catalyzed the effective carbonylation reaction with CO 2 under mild reaction conditions. By altering the synthetic environment, a series of uniform mesoporous CeO 2 particles with atomically aligned single-crystal frameworks were constructed, which have different surface physicochemical properties and primary aggregation degree. The prepared mesoporous CeO 2 single-crystal achieved efficient activation of CO 2 and alcohols at 0.5 MPa CO 2 and 100 °C, and the CeO 2 -IL-M catalyst shows optimal catalytic performance in the synthesis of ethylene carbonate with 46.22 mmol g –1 h –1 , which was 50.6 times as high as that of the CeO 2 obtained without ionic liquids. Subsequently, the catalytic pathway and mechanism of carbonylation reaction with CO 2 on mesoporous CeO 2 single-crystal were studied via React-IR spectra and C 18 O 2 labeling experiments. The research provides a new strategy for controllable nanoscale assembly of mesoporous single-crystal materials and expands the application range of single-crystal materials, aiming to develop novel catalytic materials to meet industrial needs.
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NANOTECHNOLOGY
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2013
·Vol. 24
·期 14
·145101
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IF 3.842
Dao-Lu Tang,Fei Song,Cheng Chen,Xiu-Li Wang,Yu-Zhong Wang
Increasing attention has recently been paid to the fabrication of drug delivery systems with excellent cell internalization and intracellular drug release properties. In this study, an amphiphilic block copolymer of chitosan was synthesized for the first time, which can self-assemble into micelles in a neutral aqueous solution but partially disassemble in an acidic endosomal/lysosomal environment. The antitumor drug, camptothecin (CPT), was encapsulated in the cores of the micelles for tumor cell therapy. In vitro drug release studies demonstrated that the micelles presented a much faster release of CPT at pH 5.0 than at pH 7.4. Blank micelles were found to be nontoxic in preliminary in vitro cytotoxicity assays. Cell experiments showed that the CPT-loaded micelles could be effectively internalized by Hela cells and accomplished a potent antitumor cell efficacy, indicating that the chitosan-based micelles might be an attractive new platform for efficient intracellular drug delivery.
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PubMed
高影响因子
NANOTECHNOLOGY
·
2013
·Vol. 24
·期 34
·345602
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IF 3.842
Hongtao Cui,Yan Liu,Wanzhong Ren,Minmin Wang,Yunan Zhao
In this work, SnO2 quantum dots with high crystallinity were synthesized on a large scale under mild reaction conditions via an epoxide precipitation route. The SnO intermediate, which was produced in the reactions between epoxide and [Sn(H2O)6]2+, was converted to SnO2 quantum dots by the oxidation of H2O2. It is believed that the protonation and the following ring opening of epoxide promoted the hydrolysis and condensation of [Sn(H2O)6]2+ to form the intermediate. The obtained quantum dots had a maximum specific capacitance of 204.4 F g−1 at a scan rate of 5 mV s−1 in 1 mol l−1 KOH aqueous solution. The electrochemical measurements proved that this high specific capacitance of SnO2 resulted from the Faradaic reactions between SnO2 and the electrolyte. This demonstrates for the first time that SnO2 can be used as a pseudocapacitive electrode material.
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高影响因子
NANOTECHNOLOGY
·
2013
·Vol. 24
·期 20
·205601
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IF 3.842
Bin Xu,Bing Cai,Ming Liu,Hongsong Fan
This study explored a simple and fast method utilizing ultraviolet (UV) irradiation to synthesize CdTe/CdS/ZnS QDs in aqueous solution. Based on the reaction of photolysis and chemical deposition, the CdS and ZnS shell can be successively deposited around the thiol-capped CdTe cores through the interaction of Cd2+/Zn2+ and S2− produced by UV irradiation. The effect of the UV irradiation time, the ratios of thioglycolic acid (TGA)/Cd and TGA/Zn on the shell formation, shell stability, and the photoluminescence (PL) intensity of the QDs, was systematically investigated. Keeping the ratio of TGA/Cd, increasing UV irradiation time from 30 to 120 s, the blue-shift of the fluorescence emission peak position of CdTe/CdS QDs was observed. As the irradiation time increased continuously from 120 to 300 s, the red-shift of the emission peak position was observed. In the total irradiation time, the PL intensity of all the samples was enhanced. By applying 300 s irradiation on the samples, the emission peak was blue-shifted at a fixed TGA/Cd ratio of 1:1 and red-shifted at the ratios of 2:1, 4:1, 8:1, and 13:1. The PL intensity reached its highest value at the ratio of 2:1. The effect of TGA/Zn ratio on ZnS shell formation showed a similar progress. Under an optimum synthesized reaction condition, the particle sizes of CdTe core, CdTe/CdS core–shell and CdTe/CdS/ZnS core–shell–shell QDs were 2.6 nm, 3.4 nm, and 4.6 nm respectively. This study confirmed that with the core–shell–shell structure, CdTe/CdS/ZnS QDs had high anti-oxidability, photostability, and low toxicity. Therefore they can be further used in cell imaging efficiently.
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高影响因子
NANOTECHNOLOGY
·
2013
·Vol. 24
·期 36
·365101
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IF 3.842
Fangkai Du,Yunhao Ming,Fang Zeng,Changmin Yu,Shuizhu Wu
Intracellular pH plays a critical role in the function of cells, and its regulation is essential for most cellular processes. In this study, we demonstrate a fluorescence resonance energy transfer (FRET)-based ratiometric pH nanosensor with carbon-dot (CD) as the carrier. The sensor was prepared by covalently linking a pH-sensitive fluorescent dye (fluorescein isothiocyanate, FITC) onto carbon-dot. As the FRET donor, the carbon-dot exhibits bright fluorescence emission as well as λex-dependent photoluminescence emission, and a suitable excitation wavelength for the donor (CD) can be chosen to match the energy acceptor (fluorescein moiety). The fluorescein moieties on a CD undergo structural and spectral conversion as the pH changes, affording the nanoplatform a FRET-based pH sensor. The CD-based system exhibits a significant change in fluorescence intensity ratio between pH 4 and 8 with a pKa value of 5.69. It also displays excellent water dispersibility, good spectral reversibility, satisfactory cell permeability and low cytotoxicity. Following the living cell uptake, this nanoplatform with dual-chromatic emissions can facilitate real-time visualization of the pH evolution involved in the endocytic pathway of the nanosensor. This reversible and low cytotoxic fluorescent nanoplatform may be highly valuable in a variety of biological studies, such as endocytic trafficking, endosome/lysosome maturation, and pH regulation in subcellular organelles.
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CHINESE JOURNAL OF CATALYSIS
·
2024
·
IF 15.7
Lulu Sun,Shiyang Liu,Taifeng Liu,Dongqiang Lei,Nengchao Luo,Feng Wang
ABSTRACT Photocatalytic decomposition of sugars is a promising way of providing H 2 , CO, and HCOOH as sustainable energy vectors. However, the production of C 1 chemicals requires the cleavage of robust C−C bonds in sugars with concurrent production of H 2 , which remains challenging. Here, the photocatalytic activity for glucose decomposition to HCOOH, CO (C 1 chemicals), and H 2 on Cu/TiO 2 was enhanced by nitrogen doping. Owing to nitrogen doping, atomically dispersed and stable Cu sites resistant to light irradiation are formed on Cu/TiO 2 . The electronic interaction between Cu and nitrogen ions originates valence band structure and defect levels composed of N 2 p orbit, distinct from undoped Cu/TiO 2 . Therefore, the lifetime of charge carriers is prolonged, resulting in the production of C 1 chemicals and H 2 with productivities 1.7 and 2.1 folds that of Cu/TiO 2 . This work provides a strategy to design coordinatively stable Cu ions for photocatalytic biomass conversion.
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TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
·
2024
·
IF 4.7
Yi ZHANG,Han-xiao LIAO,Lu YANG,Bin-hua ZHOU,Xuan-zhi LIU,Huan-huan ZHAI,Xiao-rong HE,Hong-jun HUANG,Peng-fei TAN,Jun PAN
In order to address the issue that the photocatalytic reduction of hexavalent chromium (Cr(VI)) is often limited by the inefficient utilization of electrons in photocatalysts, a quasi-MOF photocatalyst using thiocyanate (—SCN) was developed as a modulator to enhance the charge transfer properties of ZIF-L-based photocatalysts. The incorporation of —SCN introduced structural defects, which improved visible light absorption and the reduction ability of photogenerated electrons. —SCN significantly adjusted the electronic properties and established a stable electron release pathway, serving as active sites for reduction. The optimized quasi-MOF demonstrated a Cr(VI) reduction rate of 94.8% in neutral potassium thiocyanate solution under visible light without a hole scavenger. The reaction rate constant is 2.8 times that of the photocatalyst without defect modulation. This study offers a promising strategy for developing highly efficient photocatalysts for environmental remediation.
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CHINESE JOURNAL OF CATALYSIS
·
2024
·
IF 15.7
Zuo-Shu Sun,Xue-Yan Xiang,Qiu-Ping Zhao,Zhao Tang,Shi-Yi Jiang,Tong-Bu Lu,Zhi-Ming Zhang,Baifan Wang,Hua-Qing Yin
Electrocatalytic urea synthesis provides a favorable strategy for conventional energy-consuming urea synthesis, but achieving large-scale catalyst synthesis with high catalytic efficiency remains challenging. Herein, we developed a simple method for the preparation of a series of FeNi-alloy-based catalysts, named FeNi@ n C- T ( n represents the content of nanoporous carbon as 1, 3, 5, 7 or 9 g and T = 900, 950, 1000 or 1100 °C), for highly performed urea synthesis via NO 3 − and CO 2 co-reduction. The FeNi@7C-1000 achieved a high urea yield of 1041.33 mmol h −1 g FeNi −1 with a Faradaic efficiency of 15.56% at –1.2 V vs . RHE. Moreover, the scale-up synthesized FeNi@7C-950-S (over 140 g per batch) was achieved with its high catalytic performance and high stability maintained. Mechanism investigation illuminated that the Ni and Fe sites catalyze and stabilize the key *CO and *N intermediates and minimize the C–N coupling reaction barriers for highly efficient urea synthesis.
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