Search

[Display omitted] • CDI technology is feasible and effective for arsenic removal. • The developed flexible self-supporting electrode has great application prospects. • The introduction of NCDs improves electrosorption capacity of rGO electrode. • Some highly toxic As(III) is oxidized to less toxic As(V) during the electrosorption process. Capacitive deionization (CDI) technology has promising applications for the removal of arsenic from micro polluted water. The selection of electrode materials and the fabrication of electrodes are the core parts of the CDI technology. In this paper, the structure of graphene was modulated by inserting carbon quantum dots to form three-dimensional (3-D) rGO/NCDs electrode material and electrospinning method was applied to fabricate monolithic mesh self-supporting electrodes with excellent electrochemical and structure properties. In the experiments of arsenic removal, the rGO/NCDs electrode achieved an electrosorption capacity of 15.07 mg g−1 at 1.0 V, increasing by 29.5% compared with that of rGO electrode. In addition, the model fitting analysis of the experimental data showed that arsenic removal was consistent with pseudo-first-order kinetic model and Langmuir adsorption isotherm. The thermodynamic model suggested that electrosorption was a spontaneous exothermic process. The intraparticle diffusion model further revealed the diffusion mechanism of arsenic removal by CDI electrodes. In conclusion, the prepared flexible self-supporting rGO/NCDs electrode with high electrosorption capacity provided a new idea for the electrode preparation process and further promoted the large-scale application of CDI technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • CDI technology effectively removed Pb2+ from slightly-polluted water. • The doping of NCDs improved the structural and electrochemical properties. • A monolithic mesh electrode was prepared by electrospinning method. • The Langmuir isotherm and the pseudo-first-order model fitted the electrosorption. • The hydrated radius and valence affected the order of ion adsorption. Capacitive deionization (CDI) technology is an effective method for the removal of Pb2+ from slightly-polluted water. In this study, reduced graphene oxide/nitrogen-doped carbon quantum dots (rGO/NCDs) composites with different NCDs mass ratios were successfully synthesized by hydrothermal method and the preparation process of CDI electrode was optimized by electrospinning method to obtain monolithic mesh-like structure. The results showed that the doping of NCDs improved the structural and electrochemical properties of the composites. rGO/25%NCDs composite possessed well-developed three-dimensional porous structure, high specific surface area (347.65 m2/g) and excellent specific capacitance (284.0 F/g). The prepared CDI electrodes had a fish scale-like graded interfacial structure, and this unique structure made the electrodes exhibit superhydrophilic property. The results of CDI tests showed that the electrosorption capacity of rGO/25%NCDs electrode could reach 19.26 mg/g which was higher than that of the pure rGO electrode and many reported electrodes, when the initial concentration of Pb2+ was 5 mg/L and the voltage was −1.0 V. The adsorption process was consistent with the Langmuir adsorption isotherm and the pseudo-first-order kinetic model. In addition, the study on the competitive adsorption in a co-existed system revealed that the electrosorption capacity was strongly dependent on the ionic valence rather than hydrated radius. [ABSTRACT FROM AUTHOR]

Fibrous nanocomposites of carbon nanotubes, graphene-oxide or graphene were prepared by a simple coagulation spinning technique exhibiting synergetic enhancement of mechanical strength, electronic conductivity and electrical actuation performance. [ABSTRACT FROM AUTHOR]

Strain Sensors: Porous Fibers Composed of Polymer Nanoball Decorated Graphene for Wearable and Highly Sensitive Strain Sensors (Adv. Funct. In article number 1903732, Peng He, Guqiao Ding, and co-workers prepare a porous composite fiber composed of graphene networks and decorated polymer nanoballs for wearable strain sensors. With an optimized graphene-polymer interface area, these fibers show excellent sensitivity, a low detection limit, and long durability to small strains, which enables weaving into fabrics for motion and location detection. [Extracted from the article]

Wearable textile strain sensors that can perceive and respond to human stimuli are an essential part of wearable electronics. Yet, the detection of subtle strains on the human body suffers from the low sensitivity of many existing sensors. Generally, the inadequate sensitivity originates from the strong structural integrity of the sensors because tiny external strains cannot trigger enough variation in the conducting network. Inspired by the rolling friction where the interaction is weakened by decreasing interface area, porous fibers made of graphene decorated with nanoballs are prepared via a prolonged phase‐separation process. This novel structure confers the graphene fibers with high gauge factors (51 in 0–5% and 87 in 5–8%), which is almost 10 times larger than the same structures without nanoballs. A low detection limit (0.01% strain) and good durability (over 6000 circles) are obtained. By the virtue of these qualities, these fiber‐based textile sensors can recognize a pulse wave and eyeball movement in real‐time while keeping comfortable wearing sense. Moreover, by weaving such fibers, the electronic fabrics with a specially designed structure can distinguish the multilocation in real time, which shows great potential as wearable electronics. [ABSTRACT FROM AUTHOR]

Developing low cost, highly efficient, and long-term stability electrocatalysts are critical for direct oxidation methanol fuel cell. Despite huge efforts, designing low-cost electrocatalysts with high activity and long-term durability remains a significant technical challenge. Here, we prepared a new kind of platinum-nickel catalyst supported on silane-modified graphene oxide (NH 2 -rGO) by a two-step method at room temperature. Powder X-ray diffraction, UV–vis spectroscopy, Raman, FTIR spectroscopy and X-ray photoelectron spectroscopy results confirm that GO was successfully modified with 3-aminopropyltriethoxysilane (APTES), which helps to uniformly disperse PtNi nanoparticles. Cyclic voltammetry, chronoamperometry, CO-stripping and rotating disk electrode (RDE) results imply that PtNi/NH 2 -rGO catalyst has significantly higher catalytic activity, enhance the CO toxicity resistance, higher stability and much faster kinetics of methanol oxidation than commercial Pt/C under alkaline conditions. [Display omitted] • Silane-modified graphene oxide (NH 2 -rGO) is synthesized. • PtNi nanoparticles are highly dispersed on NH 2 -rGO support. • Pt 8 Ni 2 /NH 2 -rGO exhibited superior activity towards methanol oxidation. • Pt 8 Ni 2 /NH 2 -rGO had better CO poisoning tolerance and much faster kinetics of methanol oxidation. [ABSTRACT FROM AUTHOR]