Chenfei Yu

Dopamine fluorescent sensors based on polypyrrole/graphene quantum dots core/shell hybrids.

A facilely prepared fluorescent sensor was developed for dopamine (DA) detection with high sensitivity and selectivity based on polypyrrole/graphene quantum dots (PPy/GQDs) core/shell hybrids. The composites exhibit strong fluorescence emission, which is dramatically enhanced as high as three times than pristine GQDs. The prepared sensor allows a highly sensitive determination of DA by fluorescent intensity decreasing with the addition of DA and presents a good linearity in range of 5-8000 nM with the detection limit of 10 pM (S/N = 3). Furthermore, the application of the proposed approach have been demonstrated in real samples and showed promise in diagnostic purposes.

Ultrasensitive dopamine sensor based on novel molecularly imprinted polypyrrole coated carbon nanotubes

A novel electrochemical sensor using the molecularly imprinted (MIP) oxygen-containing polypyrrole (PPy) decorated carbon nanotubes (CNTs) composite was proposed for in vivo detection of dopamine (DA). The prepared sensor exhibits a remarkable sensitivity of (16.18μA/μM) with a linear range of 5.0×10(-11)-5.0×10(-6)M and limit of detection as low as 1.0×10(-11)M in the detection of DA, which might be due to the plenty cavities for binding DA through π-π stacking between aromatic rings and hydrogen bonds between amino groups of DA and oxygen-containing groups of the novel PPy.

A facilely prepared polypyrrole–reduced graphene oxide composite with a crumpled surface for high performance supercapacitor electrodes

A polypyrrole–reduced graphite oxide core–shell composite was facilely fabricated through electrostatic interactions and π–π accumulation. This novel composite shows remarkable performance as an electrode material for supercapacitors, with a high specific capacitance of 557 F g−1 at a current density of 0.5 A g−1, and retains a high value after 1000 charge–discharge processes. The maximum energy density of the fabricated supercapacitor based on the mass of active electrodes is calculated to be 49.5 W h kg−1 and 33.3 W h kg−1 at a power density of 0.22 kW kg−1 and 6.06 kW kg−1, the improved capacitance might be mainly ascribed to higher conductivity and more crumpled surface of the composite.

All-solid-state flexible supercapacitors based on highly dispersed polypyrrole nanowire and reduced graphene oxide composites.

Highly dispersed polypyrrole nanowires are decorated on reduced graphene oxide sheets using a facile in situ synthesis route. The prepared composites exhibit high dispersibility, large effective surface area, and high electric conductivity. All-solid-state flexible supercapacitors are assembled based on the prepared composites, which show excellent electrochemical performances with a specific capacitance of 434.7 F g(-1) at a current density of 1 A g(-1). The as-fabricated supercapacitor also exhibits excellent cycling stability (88.1% capacitance retention after 5000 cycles) and exceptional mechanical flexibility. In addition, outstanding power and energy densities were obtained, demonstrating the significant potential of prepared material for flexible and portable energy storage devices.

Highly dispersed carbon nanotube/polypyrrole core/shell composites with improved electrochemical capacitive performance

Highly dispersed polypyrrole (PPy) is firstly designed for decorating onto the surface of pristine multiwalled carbon nanotubes (CNTs), then used in the facile synthesis of a CNT/PPy core/shell composite, which provides a potential application for further modification as a base-material due to its high dispersibility. The hybrid material with a PPy shell thickness of 1.61 nm displayed a high specific capacitance of 276.3 F g−1 in 1 M KCl electrolyte, four times higher than pristine CNT. Such an improvement in performance is closely correlated with the integrated advantage of the decorated PPy shell, which enhanced the dispersibility and active surface area.

Facile Synthesis of Molecularly Imprinted Graphene Quantum Dots for the Determination of Dopamine with Affinity-Adjustable.

A facilely prepared fluorescence sensor was developed for dopamine (DA) determination based on polyindole/graphene quantum dots molecularly imprinted polymers (PIn/GQDs@MIPs). The proposed sensor exhibits a high sensitivity with a linear range of 5 × 10(-10) to 1.2 × 10(-6) M and the limit of detection as low as 1 × 10(-10) M in the determination of DA, which is probably due to the tailor-made imprinted cavities for binding DA thought hydrogen bonds between amine groups of DA and oxygen-containing groups of the novel composite. Furthermore, the prepared sensor can rebind DA in dual-type: a low affinity type (noncovalent interaction is off) and a high affinity type (noncovalent interaction is on), and the rebinding interaction can be adjusted by tuning the pH, which shows a unique potential for adjusting the binding interaction while keeping the specificity, allowing for wider applications.

In situ polymerization of highly dispersed polypyrrole on reduced graphite oxide for dopamine detection.

A composite consisting of reduced graphite oxide and highly dispersed polypyrrole nanospheres was synthesized by a straightforward technique, by in situ chemical oxidative polymerization. The novel polypyrrole nanospheres can prevent the aggregation of reduced graphite oxide sheets by electrostatic repulsive interaction, and enhance their electrochemical properties in the nano-molar measurement of dopamine in biological systems with a linear range of 1-8000 nM and a detection limit as low as 0.3 nM.

Facile synthesis of a Co3O4@carbon nanotubes/polyindole composite and its application in all-solid-state flexible supercapacitors

A supercapacitor electrode composed of a polyindole (PIn)-modified carbon nanotubes (CNTs) composite (CNTs/PIn) decorated with Co3O4 nanoparticles was synthesized to enhance the electrochemical performance. The PIn shell could improve the electric conductivity and the dispersion of CNTs, and the functional groups of PIn are conducive to anchoring the Co3O4 particles on the CNTs/PIn composite with large effective surface area, leading to a high specific capacitance of 442.5 F g−1. Moreover, the all-solid-state supercapacitor exhibits a high energy density (42.9 W h kg−1) at a power density of 0.4 kW kg−1 and excellent cycling performance (90.2% capacitance retention after 5000 cycles), demonstrating its promising application as an efficient electrode material for electrochemical capacitors.

Gold nanoparticles coated polystyrene/reduced graphite oxide microspheres with improved dispersibility and electrical conductivity for dopamine detection.

Gold nanoparticles coated polystyrene/reduced graphite oxide (AuNPs@PS/RGO) microspheres have been successfully prepared via a facile process, and the decorative gold nanoparticles could prevent the aggregation of RGO by electrostatic repulsive interaction, and lead to high dispersibility of the composite. The prepared composite has a highly increased conductivity of 129Sm(-1) due to the unique electrical properties of citrate reduced gold nanoparticles. Being employed as an electrochemical sensor for detection of dopamine, the modified electrode exhibits remarkable sensitivity (3.44μA/μM) and lower detection limit (5nM), with linear response in a range of 0.05-20μM. Moreover, valid response to dopamine obtained in present work also indicates the prospective performances of AuNPs@PS/RGO microspheres to other biological molecules, such as nucleic acids, proteins and enzymes.