查找使用阿拉丁产品的科研文献

Facile fabrication of electrochemically reduced graphene oxide/polythionine-methylene blue and its use as a platform for detection of nicotinamide adenine dinucleotide in the artificial urine sample

Minling Ding,Huizhe Niu,Nan Zhang,Tongtong Hou,Ping Guan,Xiaoling Hu

Here we report on a facile, rapid, selective, and stable electrochemical sensing platform for nicotinamide adenine dinucleotide (NADH) based on polythionine-methylene blue/electrochemically reduced graphene oxide modified glassy carbon electrode (PTH-MB DES -ERG/GCE). The ERG was directly formed on a glassy carbon electrode (ERG/GCE) through one-step electrochemical reduction of GO in PBS solution (10 mM, pH 7.4). In a PBS electrolyte, respectively, containing 50% (v/v) three different deep eutectic solvents (DES), thionine and methylene blue were polymerized on the surface of ERG/GCE. The electrochemical properties of the polymers polymerized in different electrolytes were investigated. The PTH-MB DES -ERG composite has a higher performance in the electrocatalytic oxidation of NADH than that of PTH-MB DES . The as-prepared PTH-MB DES -ERG/GCE demonstrated excellent direct electrocatalytic oxidation toward NADH, providing a favorable platform for electron transfer from NADH to the electrode. The sensor displayed a wide linear range from 1.52 μM to 3333.33 μM with a limit of detection of 0.51 nM. The interference from the ascorbic acid and uric acid was negligible. The prepared sensor was further tested for the determination of NADH in artificial urine samples, showing the PTH-MB DES -ERG/GCE formed by electropolymerization have promising biomedical applications.

Simultaneous engineering on absorption window and transportation geometry of graphene-based foams toward high-performance solar steam generator

Yanjun Li,Ruhao Zan,Yuanjin Wang,Longqiang Shang,Ronghui Wu,Yue Liu,Zhenggang Rao,Kai Yao,Yi Liu,Linfeng Fei

Graphene-based materials are frequently highlighted as the candidate for solar steam generation (SSG) because of their advantages such as high solar absorption, tunable structure and low cost. However, graphene itself is not a “perfect” absorber for full solar spectrum and cannot efficiently transport water on its surface due to its intrinsic physicochemical characteristics. Here we designed and synthesized a graphene foam in a three-dimensional (3D) interconnected porous structure with silicon carbide nanoparticles anchored on graphene surfaces. The systematical characterizations confirm that the hybrid structure extends the solar absorption window of graphene in full solar spectrum; and moreover, the in situ environmental scanning electron microscopy (ESEM) experiments suggest the incorporation of SiC nanoparticles on two-dimensional graphene surface improves the condensation and transportation kinetics of water in the foam. As a result, the SSG device based on the graphene-SiC composite demonstrates an improved energy conversion efficiency up to 95% under one sun illumination compared with those of previous reported graphene-based materials. The findings may shed new light on the technologies for solar-energy-water nexus.

Microstructure and enhanced mechanical properties of ZrC/Zr composites added by in-situ Y2O3 reinforced particles

Xinjiang Zhang,Ziqing Chen,Zhaohui Liu,Meng He,Zirun Yang,Jiahui Wang

The in-situ hybrid particle-reinforcements are a novel strengthening mode for the advanced metal matrix composites . In this study, Zr matrix composites incorporating the fixed amount of ZrC particles with the different amounts of Y 2 O 3 particles were prepared by the in-situ reaction among Zr, graphite, Y, and ZrO 2 during the arc-melting. Results revealed that the graphite/Zr reaction produced the uniform in-situ ZrC particles in the Zr matrix, and the Y/ZrO 2 reaction formed the Y 2 O 3 particles. In-situ Y 2 O 3 addition refined the Zr matrix and led to the polygonal morphology of the ZrC particle. The coarser Y 2 O 3 grew in bulk, and some fine Y 2 O 3 dendrites were formed along Zr boundaries. The influence of different contents of Y 2 O 3 reinforcements on the hardness and compressive properties were analyzed. Compared with the single ZrC reinforcements, the hybrid Y 2 O 3 introduction resulted in a higher hardness and enhanced compressive strength . This hybrid structures were believed to be favorable to mechanical responses in the composites, and the relevant mechanisms for the hardening and strengthening effect of such hybrid forms were discussed.

Exquisite manipulation of two-dimensional laminar graphene oxide (GO) membranes via layer-by-layer self-assembly method with cationic dyes as cross-linkers

Yi-Hang Gu,Xi Yan,Yan Chen,Xiao-Jing Guo,Wan-Zhong Lang

Herein, we propose one novel strategy by layer-by-layer (LBL) self-assembly method to prepare two-dimensional (2D) laminar membranes assembled between sulfonated graphene oxide (S-GO) nanosheets and various cationic dyes on the polyethyleneimine (PEI) -modified Nylon-6 (PA6) substrate. The membrane performances are manipulated exquisitely by the charge of substrate, the assembled dye type, dye size, self-assembly layer number etc. The water permeance positively correlates with the height of assembled cationic dyes. The amido bonds or sulfamide bonds and π–π conjugation endow the resulted membrane with strong performance stability. Furthermore, by precisely selecting the size and charge the assembled dye, the prepared LBL GO membranes can efficiently separate mixed dyes in aqueous solution via charge repulsion or/and size sieving mechanism. For example, the separation selectivity of 39.2 for the mixed Rhodamine B/Ethyl Violet (RB/EV) dyes can be achieved with the LBL MV-0.25-2-2 membrane (it was assembled by 2 mmol L −1 Methyl violet solution for two S-GO layers with the Nylon-6 substrate modified with 0.25 wt % PEI aqueous solution). Simultaneously, the introduced cationic dyes endow these membranes with extra antibacterial capacity to both E. coli and S. aureus .

Phosphatizing engineering of heterostructured Rh2P/Rh nanoparticles on doped graphene for efficient hydrogen evolution in alkaline and acidic media

Rongfei Wang,Xiaodeng Wang,Min Cheng,Yunpeng Wei,Jihong Xia,Hua Lin,Wei Sun,Weihua Hu

A wide diversity of phosphides of platinum-group metal including Rh, Ru and Ir exhibit intriguing electrocatalytic activity toward hydrogen evolution reaction (HER). The phosphidation degree, namely the P dosage in these phosphides shows pronounced influence on the catalytic performance but is hard to control. In this work we developed a reliable strategy to synthesize Rh 2 P-based nanoparticles with controlled phosphidation degree, and investigated the influence of phosphidation degree on HER. It is found that the heterostructured Rh 2 P/Rh nanoparticle, i.e., the P-deficient composite with mixed metallic and phosphide phases, outperforms either the metallic Rh or pure Rh 2 P nanoparticles. As-synthesized Rh 2 P/Rh nanoparticles supported on P/N co-doped graphene (denoted as Rh 2 P/Rh-G) display remarkable HER activity with tiny overpotential of 17 and 19 mV at 10 mA cm −2 current density in alkaline and acid, efficiently surpassing its Rh-based rivals and benchmark Pt/C catalyst. Meanwhile it illustrates a large mass-specific activity (3.23 and 6.26 A mg −1 @50 mV overpotential in alkaline and acid, respectively) due to its high activity and low metal loading. Density functional theory (DFT) calculation indicates that the Rh 2 P/Rh heterostructured interface possesses the optimal close-to-zero value of hydrogen adsorption energy and water dissociation process is accelerated, and thus boosts HER activity.

Phase change composites of octadecane and gallium with expanded graphite as a carrier

Yuchen Yao,Yuntao Cui,Zhongshan Deng

Phase change materials (PCMs) have attracted more and more attention in the field of energy and thermal management due to the characteristic of exchanging heat with small temperature change. In order to obtain perfect PCMs, previous researchers usually prepared various phase change composites (PCCs), but there is still a gap toward the goal. Perhaps the development of PCMs with adjustable properties in a wide range to meet different needs is a feasible option. Given that the properties of organic PCMs and metal PCMs are highly complementary, using expanded graphite (EG) as a mediator, a stable PCC of octadecane and gallium that are difficult to directly mix, was successfully prepared. Octadecane and gallium are stored in the microstructures of EG, and the microstructures of EG play the role of storing nucleation embryos, and the suppression of supercooling can reach more than 86.82%. The test results showed that the properties of the PCC are indeed a balance between octadecane and gallium, and can be adjusted in a wide range. The PCC also has good structural and chemical stability, which can effectively avoid the corrosion risk caused by gallium leakage. The PCC samples containing equal amounts of gallium and paraffin were selected for thermal management performance tests. The results indicated that the PCC has application potential in related fields, and can provide a reference for the development of other PCCs.

A study of the synergetic effect between graphene oxide and transition metal oxides for energy storage

Munan Lu,Hao Li,Shijingmin Li,Fucai Yang,Yi Cao,Wenfeng Qiu

A series of graphene/transition metal oxide (TMO) composite films were prepared through an electrostatic self-assembly method. Graphene oxide (GO) sheets were decorated with Co3O4, LaCoO3, SrTiO3, NiCo2O4 and NiMoO4 nanostructures and applied as electrode materials for supercapacitors. The electrochemical properties of the GO/TMO films were tested and compared to investigate the enhancement mechanism of energy storage performance. Subsequently, the graphene matrix was designed and changed to be composed of different portions of GO and reduced graphene oxide (rGO) to study the synergetic effect between the functional groups on the graphene sheets and the TMOs. It was proved that both GO and TMOs played important roles in the electrochemical properties of the composite films. This study provided a new insight to develop GO based high-performance supercapacitor materials by a simple and low-cost way.

Characteristics of graphite oxide membranes with different thickness by low temperature thermal reduction for aqueous EDLC electrodes and hot activation phenomenon

Shuai Sun,Lei Wang,Han Xu

Reduced graphite oxide membrane (RGOM) with different thickness were prepared and used as electric double layer capacitor (EDLC) electrodes with aqueous electrolyte. According to quantum and molecular dynamic simulations, it was difficult for K + and OH − to diffuse into graphene sheets due to dense structure, which made the RGOM electrodes show poor EDLC behaviors. Electrochemical tests showed that controlling the thickness of electrodes and modifying the dense structure could improve the specific capacitance of EDLC. Further studies indicated that during galvanostatic charge/discharge processes, if the EDLC were heated at 70 °C for one cycle and then cooled down to room temperature, the specific capacitance could be increased further. Additionally, according to 10,000 times cycling tests at 5000 mA g −1 , the improved capacitance could be maintained for long time (154–167 F g −1 during test process), indicating that the hot activation could make RGOM electrodes obtain good and stable EDLC performances.

Biofunctionalized graphene oxide nanosheet for amplifying antitumor therapy: Multimodal high drug encapsulation, prolonged hyperthermal window, and deep-site burst drug release

Zhen Wang,Hao Cheng,Yu Sheng,Zongkai Chen,Xiaohong Zhu,Jianye Ren,Xiangze Zhang,Lingyu Lv,Huaqing Zhang,Jianping Zhou,Yang Ding

Biofunctional surface-modification surpassed critical limitation of graphene oxide (GO) in biocompatibility and drug delivery efficiency, contributing to versatile biomedical applications . Here, a protein corona-bridged GO nanoplatform with high drug loading, longstanding hyperthermia, and controllable drug release, was engineered for amplified tumor therapeutic benefits. Structurally, GO surface was installed with phenylboronic acid (PBA) layer, on which iRGD conjugated apolipoprotein A-I (iRGD-apoA-I) was coordinated via boron electron-deficiency, to form the sandwich-like GO nanosheet (iAPG). The GO camouflaging by iRGD-apoA-I corona provided multimodal high doxorubicin (DOX) loading by π-π stacking and coordination, and generated a higher photothermal transformation efficiency simultaneously. In vitro studies demonstrated that iAPG significantly improved drug penetration and internalization , then achieved tumor-targeted DOX release through near-infrared (NIR) controlled endo/lysosome disruption. Moreover, iAPG mediated site-specific drug shuttling to produce a 3.53-fold enhancement of tumor drug-accumulation compared to the free DOX in vivo , and induced deep tumor penetration dramatically. Primary tumor ablation and spontaneous metastasis inhibition were further demonstrated with negligible side effects under optimal NIR. Taken together, our work provided multifunctional protein corona strategy to inorganic nanomaterials toward advantageous biomedical applications.

Preparation and lubrication properties of graphene oxide/polyethylene glycol/polyvinyl alcohol composite film

Hailin Lu,Chengzhi Li,Guangshen Xu

Modified graphene oxide/waterborne epoxy composite coating with enhanced corrosion resistance

Lisheng Zhou,Pengbo Zhang,Liming Shen,Liangyong Chu,Jian Wu,Yujie Ding,Beijie Zhong,Xiaoyan Zhang,Ningzhong Bao

Waterborne epoxy (WEP) resin is drawing increasing attention due to its environmentally friendly nature. However, its application has been greatly hindered by poor corrosion resistance due to its rich inherent defects. In this work, maleic acid diamine (C 4 H 6 N 2 O 2 , MAD) modified graphene oxide (M-GO) was designed as the filler, and GO/WEP composite coatings with a high cross-linking degree, improved hydrophobicity , and high barrier properties were prepared. M-GO had a good water dispersibility and high affinity to the resin. The chemical grafting between the amino group of MAD and WEP can improve the degree of chemical cross-linking inside the coating to form a compact structure. Electrochemical impedance spectroscopy (EIS) measurements and salt spray test results indicate that the M-GO/WEP composite coating with 0.3 wt% M-GO has the best anti-corrosion performance. After being immersed in 3.5 wt% NaCl solution for 96 h, the |Z| 0.01Hz value of M-GO/WEP composite coating is 1.03 × 10 8  Ω•cm 2 , corrosion current density is 0.00040 ɥA/cm 2 and the protection efficiency reaches 99.99 %.

High-Energy-Density Asymmetric Supercapacitor Based on a Nickel Cobalt Double Hydroxide/Reduced-Graphene-Oxide Fiber Electrode

Yuexin Liu,Xiaoyu Li,Mingyuan Gao,Xuxia Hao,Jiajia Li,Ying Liu,Yanxia Li,Kefeng Cai

With high electrical conductivity, good mechanical strength, and excellent multidimensional flexibility, graphene fibers are more suitable for wearable devices than other flexible materials. However, challenges still exist in increasing their energy density. Here, we overcome this disadvantage by developing a fibrous supercapacitor loaded with battery-type active material. First, reduced-graphene-oxide fibers (rGOFs) with high conductivity and high toughness are fabricated from flake graphite by a series of redox reactions and wet-spinning processes. Second, Co-based zeolite imidazole framework (Co-ZIF) nanosheets are grown in situ on the surfaces of the rGOFs at room temperature and then converted into nickel cobalt layered double hydroxide (NCLDH) nanosheets by an etching codeposition method. The as-prepared NCLDH@rGOFs with a unique one-dimensional cladding structure exhibit an outstanding area specific capacitance of 2020 mF cm–2 at 5 mA cm–2 in a three-electrode system. When the NCLDH@rGOFs and FeOOH@rGOFs are assembled into a flexible asymmetric supercapacitor (NF-FASC), the NF-FASC shows high area specific capacitance (351.6 mF cm–2), high energy density (max. 117.3 μWh cm–2), excellent power density (max. 34 000 μW cm–2), and acceptable cycle stability (75.5% capacitance retention after 5000 cycles).