The covalent functionalization of exfoliated semiconducting MoS 2 by 1,2-dithiolanes bearing an ethylene glycol alkyl chain terminated to a butoxycarbonyl-protected amine and a photoactive pyrene moiety is accomplished. The MoS 2 -based nanohybrids were fully characterized by complementary spectroscopic, thermal, and microscopy techniques. Markedly, density functional theoretical studies combined with X-ray photoelectron spectroscopy analysis demonstrate preferential edge functionalization, primarily via sulfur addition along partially sulfur saturated zig-zag MoS 2 molybdenum-edges, preserving intact the 2D basal structure of functionalized MoS 2 -based nanohybrids as confirmed by high-resolution transmission electron microscopy and electron energy loss spectroscopy. Furthermore, in the MoS 2 -pyrene hybrid, appreciable electronic interactions at the excited state between the photoactive pyrene and the semiconducting MoS 2 were revealed as inferred by steady-state and time-resolved photoluminescence spectroscopy, implying its high potentiality to function in energy conversion schemes.

Aqueous batteries are an emerging candidate for low‐cost and environmentally friendly grid storage systems. Designing such batteries from inexpensive, abundant, recyclable, and nontoxic organic active materials provides a logical step toward improving both the environmental and economic impact of these systems. Herein the first ever battery material that works with simultaneous uptake and release of both cations and anions is proposed by coupling p‐type (bipyridinium) and n‐type (naphthalene diimide) redox moieties. It represents one of a new family of electrode materials which demonstrates an optimal oxidation potential (−0.47 V vs saturated calomel electrode), extremely fast kinetics, a highly competitive capacity (63 mA h g−1 at 4C), and cyclability in both neutral Na+ and Mg2+ electrolytes of molar range concentration. Through a combination of UV–vis spectroelectrochemistry, electrochemical quartz‐crystal microbalance, Operando synchrotron‐X‐ray diffraction, and density functional theory calculations a novel dual cation/anion insertion mechanism was proven and rationalized. Based on these findings, this innovative p/n‐type product may well provide a viable option for use as a negative electrode material, thereby promoting the design of cutting‐edge, low‐cost, rocking‐chair dual‐ion aqueous batteries.

International audienceHerein, we report a improved method for the physical grafting of 1-nitropyrene (Pyr-NO2) onto highly graphitized carbon onion. This is achieved through a lowering of the onset potential of the pyrene polymerization via in situ reduction of the NO2 group. The additional redox activity pertaining to the reduced NO2 enables exceeding the faradaic capacity which is associated with the p-doping of the grafted pyrene backbone, as observed for pyrene, 1-aminopyrene, and unreduced Pyr-NO2. Theoretical calculations demonstrate the charge transfer and binding enthalpy capabilities of Pyr-NO2, which are significantly higher than those of the other two species, and which allow for improved p-stacking on the carbon surface. Upon 20 wt % grafting of Pyr-NO2, the capacity of the electrode jumps from 20 mAh g-1 electrode to 38 mAh g-1 electrode, which corresponds to 110 mAh g-1 per mass of Pyr-NO2 and the average potential is increased by 200 mV. Very interestingly, this high performance is also coupled with outstanding retention with respect to both the initial capacity for more than 4000 cycles, as well as the power characteristics, demonstrating the considerable advantages of employing the present in situ grafting technique

Environmental degradation of transition metal disulfides (TMDs) is a key stumbling block in a range of applications. We show that a simple one-pot non-covalent pyrene coating process protects TMDs from both photoinduced oxidation and environmental aging. Pyrene is immobilized non-covalently on the basal plane of exfoliated MoS2 and WS2. The optical properties of TMD/pyrene are assessed via electronic absorption and fluorescence emission spectroscopy. High-resolution scanning transmission electron microscopy coupled with electron energy loss spectroscopy confirms extensive pyrene surface coverage, with density functional theory calculations suggesting a strongly bound stable parallel-stacked pyrene coverage of ~2–3 layers on the TMD surfaces. Raman spectroscopy of exfoliated TMDs while irradiating at 0.9 mW/4 μm2 under ambient conditions shows new and strong Raman bands due to oxidized states of Mo and W. Yet remarkably, under the same exposure conditions TMD/pyrene remain unperturbed. The current findings demonstrate that pyrene physisorbed on MoS2 and WS2 acts as an environmental barrier, preventing oxidative surface reactions in the TMDs catalyzed by moisture, air, and assisted by laser irradiation. Raman spectroscopy confirms that the hybrid materials stored under ambient conditions for two years remained structurally unaltered, corroborating the beneficial role of pyrene for not only hindering oxidation but also inhibiting aging.

Density functional studies of the edges of singlelayer 1H-MoS 2 are presented.T his phase presents ar ichv ariability of edges that can influencet he morphology and properties of MoS 2 nano-objects, play an important role in industrial chemical processes, and find future applications in energy storage, electronics and spintronics. The so-called Mo-100 %S edges vertical S-dimersw ere confirmedt ob e stable, however the authors also identified af amilyo fm etastable edges combining Mo atoms linked by two-electron donor symmetrical disulfide ligandsa nd four-electron donor unsymmetrical disulfide ligands. These may be entropically favored, potentially stabilizing them at high temperatures as a" liquid edge" phase. For Mo-50 %S edges, S-bridge structures with 3 periodicity along the edge are the most stable, compatible with aP eierls' distortion arising from the d-bands of the edge Mo atoms.A na dditional explanation for this periodicity is proposed through the formation of 3center bonds.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.

Pyrene carrying an 1,2-dithiolane linker was employed to functionalize exfoliated WS2 and the resulting material used in a proof-of-concept application as a photoresistor type sensor. The WS2-pyrene hybrid material was...

In article number https://doi.org/10.1002/aenm.201701988, Joël Gaubicher, Philippe Poizot, Fabrice Odobel and co‐workers report the first ever battery material that works with simultaneous uptake and release of both cations and anions. This represents one of a new family of organic electrode materials that shows great promise, thereby promoting the design of cutting‐edge, low‐cost, rocking‐chair dual‐ion aqueous batteries.

No abstract