A nanocomposite of HKUST‐1 (MOF) and electroreduction graphene oxide (ERGO) is prepared and applied as an electrochemical sensor for the simultaneous determination of paracetamol and dopamine by means of one‐step electrodeposition. The MOF/ERGO composite displays excellent electrochemical catalytic activities towards the paracetamol and dopamine, which is attributed to the synergistic effect of big surface area, porosity and high electrocataytic activity of the MOF and good conductivity of ERGO. The modified electrode could be applied to determine simultaneously paracetamol and dopamine in biochemical samples with wide linear ranges (0.2 μM to 160 μM for paracetamol and 0.2 μM to 300 μM for dopamine) and low detection limits (0.016 μM for paracetamol and 0.013 μM for dopamine). Meanwhile, the proposed sensor still displays high sensitivity, good selectivity and excellent stability.

The main challenge in developing foldable Li–S batteries (LSB) lies in developing an electrode that is ultraflexible, conductive, and catalytic for dissolved lithium polysulfides (LiPSs). In this paper, lightweight macromolecule graphitic carbon nitride (g‐C3N4) film and a conductive polymer (CP) of poly(3,4‐ethylenedioxythiophene) shell are introduced into flexible LSBs by compositing with carbon cloth (CC). In the designed hybrid of CP/g‐C3N4@CC, 2D g‐C3N4 is used in the form of an effective trapper and functions as a continuous catalytic layer for LiPSs via the formation of pyridinic‐N‐Li bonds. This is revealed by both experimental investigations and theoretical analysis. The sandwich‐like CC and CP simultaneously bring an omnidirectional conductive network for fast interfacial reaction kinetics. With these benefits, the self‐supported CP/g‐C3N4@CC forms a powerful interaction system to fully in situ “lock” LiPSs in the commercial CC matrix. Thus, a substantially enhanced electrochemical performance is obtained at a high sulfur loading (4.7 mg cm–2) even operating in a pouch cell. This work may provide a potential avenue for practical use of high‐performance LSBs toward flexible energy‐storage devices.

In this paper, we studied the following Caputo fractional difference boundary value problem (FBVP):where 2 < ν ≤ 3 is a real number, ν C y(t) is the standard Caputo difference. By means of cone theoretic fixed point theorems, some results on the existence of one or more positive solutions for the above Caputo fractional boundary value problems are obtained. MSC: 26A33; 39A05; 39A12

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