A novel signal on-off type photoelectrochemical (PEC) biosensing system was designed for sensitive detection of carcinoembryonic antigen (CEA) based on tin disulfide nanosheets loaded on reduced ...graphene cxide (SnS2-GR) as the photoactive material and gold nanoparticles coated on reduced graphene oxide-functionalized copper sulfide (Au@CuS-GR) for signal amplification. It's the first time for SnS2-GR was exploited as a sensing matrix. Here, the photocurrent signals of SnS2 were amplified attributed to the sensitization effect of graphene. As signal amplifier, Au@CuS-GR could quench the photocurrents of SnS2-GR not only through the p-n type semiconductor quenching effect as well as the steric hindrance effect, but also as peroxidase mimetics to catalyze the oxidation of 4-Chloro-1-naphthol (4-CN) to produce insoluble product on the electrode surface. Based on the multiple signal amplification ability of Au@CuS-GR, CEA was detected sensitively with a linear range from 0.1 pg mL−1 to 10 ng mL−1 and limit of detection down to 59.9 fg mL−1 (S/N = 3). Meanwhile, the PEC biosensor displayed excellent performance in the assay of human serum sample, showing good application prospects for various target analysis.
•This is the first time that SnS2-GR and Au@CuS-GR was used to constructed PEC biosensor.•Au@CuS-GR had several quenching effects on the photocurrent of SnS2-GR/ITO.•The PEC biosensor showed a low detection limit of 0.0559 pg mL−1 for CEA..
Let $P(H)$ be the power set of $H$. Consider $\ds P^*(H)=P(H)\setminus\{\phi\}$. A hyperoperation on a nonempty set $H$ is a function $\ds\circledast:H\times H\rightarrow P^*(H).$ A set $H$ endowed ...with a family $\Gamma$ of hyperoperations is called ahyperstructure. Hyperstructures have many applications to several sectors of both pure and applied sciences. One of the well developed hyperstructures is the hyper BCI-algebra. Recently, by following this hyperstructure, a new hyperstructure was created by Indangan et al., named as hyper GR-algebras. In this paper, fuzzy set and intuitionistic fuzzy set are applied to hyper GR-algebra. Particularly, the fuzzy hyper GR-ideal of type 1 and the intuitionistic fuzzy hyper GR-ideal are introduced, and a relationship between them are obtained. Moreover, some of their characterizations are established by the use of their level subsets.Â
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Preparation of free-standing electrode materials with three-dimensional network architecture has emerged as an effective strategy for acquiring advanced portable and wearable power ...sources. Herein, graphene/vanadium oxide (GR/V2O5) free-standing monolith composite has been prepared via a simple hydrothermal process. Flexible GR sheets acted as binder to connect the belt-like V2O5 for assembling three-dimensional network architecture. The obtained GR/V2O5 composite can be reshaped into GR/V2O5 flexible film which exhibits more compact structure by ultrasonication and vacuum filtration. A high specific capacitance of 358Fg−1 for GR/V2O5 monolith compared with that of GR/V2O5 flexible film (272Fg−1) has been achieved in 0.5molL−1K2SO4 solution when used as binder free electrodes in three-electrode system. An asymmetrical supercapacitor has been assembled using GR/V2O5 monolith as positive electrode and GR monolith as negative electrode, and it can be reversibly charged-discharged at a cell voltage of 1.7V in 0.5molL−1 K2SO4 electrolyte. The asymmetrical capacitor can deliver an energy density of 26.22Whkg−1 at a power density of 425Wkg−1, much higher than that of the symmetrical supercapacitor based on GR/V2O5 monolith electrode. Moreover, the asymmetrical supercapacitor preserves 90% of its initial capacitance over 1000 cycles at a current density of 5Ag−1.
•Several innovative and cost effective synthesis processes have been studded.•Characterizations of graphene based advanced supercapacitor electrodes are found.•Electrochemical properties of graphene ...associated supercapacitor electrodes are intensively surveyed.
The accelerated growth of renewable energy conversion and storage devices with significantly greater efficiency, stable operation, cost effectiveness, and user-friendly environment manifests a challengeable approach to mitigate the global energy crisis. This review focuses on studies carried out regarding various energy storage mechanisms, so as to design and develop sundry materials for accomplishing most suitable (high energy density and long term excellent stability) supercapacitor electrodes. The present review specifically strikes the works on electrode materials such as carbides, phosphides, sulphides, polymers, oxides, and nitrides with graphene.
It is visualized from the study that graphene with metal sulphides yield high specific capacitance, energy density, power density and cyclic stability compared to graphene with carbides, nitrides, phosphides, oxides, and polymers thereby ensuring their commercial potentials.
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