Abstract The nanohybrids of noble metal (M=Ag, Au, Pd, Pt, and Ru) nanoparticle-decorated rhenium disulfide nanosheets (ReS2 NSs) were demonstrated as excellent catalysts towards the reduction of aromatic nitro compounds. The M/ReS2 nanohybrids were synthesized by facile hydrothermal method and characterization results proved that each metal nanoparticle was anchored on the ReS2 NSs. These nanohybrids exhibited superior catalytic performance towards the reduction of aromatic nitro compounds including 4-nitrophenol, 2-nitroaniline, and nitrobenzene. Interestingly, the Ru/ReS2 and Pd/ReS2 showed enhanced catalytic reduction compared to Ag/ReS2, Au/ReS2, and Pt/ReS2 and also showed significant catalytic stability due to metal nanoparticles anchored strongly on the surface of ReS2 NSs. Moreover, these M/ReS2 nanohybrids turned out to have much better catalytic performance compared to noble metal nanoparticle-based catalysts. A plausible reduction mechanism was proposed for each nitro compound. It was verified that the metal-nanoparticle-mediated hydrogen transfer was involved in the reduction of nitro compounds to amines. This report demonstrates the catalytic activities for metal nanoparticle-decorated ReS2 nanohybrids, which can serve as a paradigm to open up a future trend in the design of transition metal dichalcogenides nanohybrids as superior catalysts.

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Abstract The present investigation mainly addresses the open circuit voltage (Voc) issue in kesterites based Cu2ZnSn(S,Se)4 solar cells by simply introducing alkali metal fluoride nanolayers (  several nm NaF, or LiF) to lower the work functions of the front İTO\} contacts without conventional hole-blocking ZnO layers. Kelvin probe measurements confirmed that the work function of the front İTO\} decreases from 4.82 to 3.39 and 3.65 eV for NaF and LiF, respectively, resulting in beneficial band alignment for electron collection and/or hole blocking on top electrodes. Moreover, a 10.4% power conversion efficiency ( 11.5% in the cell effective area) \{CZTSSe\} cell with improved Voc of up to 90 mV has been attained. This demonstration may provide a new direction of further boosting the performance of copper chalcogenide based solar cells as well.

In this study, we developed highly dispersed rhenium nanoparticles decorated on activated carbon (Re@CDACs). The activated carbons were derived from the biomass raw materials cardamom pods (Elettaria cardamomum L) via carbonization followed by activation with ZnCl2 at high temperature. The Re NPs synthesis was achieved by decomposition of [Re2(CO)10] complex via a facile microwave thermal reduction technique. The as-prepared Re@CDACs nanocomposites were characterized by a combination of state-of-the-art techniques. The Re@CDACs nanocomposites so prepared were utilized for electrocatalytic oxidation of sunset yellow (SY) and supercapacitor applications. The Re@CDACs-modified electrodes were found to show extraordinary electrochemical performance for sensitive and selective detection of SY with a wide linear range of 0.05–390 μM and a detection limit and sensitivity of 16 nM (S/N = 3) and 91.53 μA μM−1, respectively, surpassing other modified electrodes. Moreover, these Re@CDACs catalysts were also found to exhibit a higher specific capacitance of 181 F g-1 at a current density of 1.6 A g−1 in 1.0 M H2SO4 electrolyte. The specific capacitance retention of 90% was achieved after 2500 cycles at current density 2.0 A g−1. Therefore, we have demonstrated that the Re@CDACs nanocomposite materials could be used as a promising electrode material in electrochemical oxidation of SY and energy storage applications. © 2018

Polyethersulfone ionomers containing quaternary ammoniums were prepared for the applications on alkaline anion exchange membrane (AAEM) fuel cells. The ionomers were synthesized from 2,2′-dimethyl-4,4′-biphenyldiol and bis(4-chlorophenyl) sulfone via nucleophilic substitution followed by bromination, quaternization and anion exchange reaction. The biphenyl structure in polymer main chain exhibited atropisomerism after bromination, leading to the anisochronous signals of geminal protons on bromomethyl groups in 1H NMR spectra. Model compounds were synthesized to confirm the atropisomerism by EI mass and 1H NMR spectra. The resonance peaks from five possible repeating units of brominated polyethersulfones in the 1H NMR spectra were identified and discussed in detail. The rotational barriers of biphenyl structures containing brominated methyl groups at 2 and 2′ positions were calculated by density functional theory. The properties of these polyethersulfone anion exchange membranes (AEMs) were characterized. Their IECs ranged from 0.81 to 1.75 mequiv/g. The corresponding water uptakes and dimensional changes were in the ranges of 19–42% and 12–38%, respectively. The tensile strength of an AEM (1.75MQAPES-OH) with an IEC of 1.75 mequiv/g remained 17 MPa even though the water uptake was 42%. The hydroxide conductivity of 1.75MQAPES-OH could reach 51.4 mS/cm at 98%RH and 80 °C. After alkaline stability test for 168 h, the AEMs degraded slightly in terms of their IECs and hydroxide conductivity.

The fluorogenic aptamer sensing of interferon-gamma (IFN-γ) was scrutinized using two-dimensional (2D) ReS2 and TiS2 nanosheets (NSs) as a platform. The IFN-γ an important cytokine, functions as a bio-indicator to detect infectious diseases such as tuberculosis and human immunodeficiency virus. This 2D NSs based aptamer sensor was implemented to induce the fluorescence off/on resulting from an aptamer, in the absence or presence of a target to be probed. The fluorescence emitting from the aptamer is quenched by interacting with NSs, while the ensuing fluorescence is recovered upon addition of target. Such a fluorescence off/on mechanism was proposed based on the behavior of fluorescence resonance energy transfer (FRET) between the aptamer and NSs. The fluorescence response exhibits linearity as a function of target, and the detection limit of IFN-γ was evaluated to be 57.6 and 82.7 pM for ReS2 and TiS2 NSs, respectively, being comparable to or even better than those methods adopted for probing IFN-γ. The selectivity property was also characterized with various targets, exhibiting a very specific selectivity for IFN-γ. The findings reveal that the aptamer-transition metal dichalcogenides (TMD) NSs will be a great sensing pair to the development of aptamer-based biosensors. Moreover, the biocompatibility and sensing capability of IFN-γ was implemented in human embryonic kidney 293T (HEK) live cells. This is the first report to emerging fluorogenic sensing of IFN-γ aptamer with 2D TMD, showing a promising trend for future design of biosensors. © 2017 Elsevier B.V.

Iodine monochloride (ICl) elimination from one-photon dissociation of CH2ICl at 248 nm is monitored by cavity ring-down absorption spectroscopy (CRDS). The spectrum of ICl is acquired in the transition of B3 0X1 + and is confirmed to result from a primary photodissociation, that is, CH2ICl + h→CH2 + ICl. The vibrational population ratio is determined with the aid of spectral simulation to be 1:(0.36 ± 0.10):(0.11 ± 0.05) for the vibrational levels = 0, 1, and 2 in the ground electronic state, corresponding to a Boltzmann-like vibrational temperature of 535 ± 69 K. The quantum yield of the ICl molecular channel for the reaction is obtained to be 0.052 ± 0.026 using a relative method in which the scheme CH2Br2 →CH2 + Br2 is adopted as the reference reaction. The ICl product contributed by the secondary collisions is minimized such that its quantum yield obtained is not overestimated. With the aid of the CCSD(T)//B3LYP/MIDI! level of theory, the ICl elimination from CH2ICl is evaluated to follow three pathways via either (1) a three-center transition state or (2) two isomerization transition states. However, the three-center concerted mechanism is verified to be unfavorable. © 2018 American Chemical Society.

We report the use of palladium nanoparticles (Pd NPs) immobilized on m-aminophenol/formaldehyde resin (APF)-derived porous carbon spheres (Pd@PCS) as heterogeneous catalysts for the reduction of organic dyes. The morphology, structure, surface compositions, and textural properties of PCS and the Pd@PCS catalyst were characterized fully to document the excellent catalytic efficiency of Pd@PCS composites. Pd NPs of mean particle size ca. 12 ± 0.8 nm were highly dispersed on the surface of PCSs, and possessed surface area and pore volume as high as 896.3 m2 g-1 and 0.934 cm3 g-1, respectively. Prepared catalysts were applied to the reduction of various organic dyes; high catalytic activity towards crystal violet, eosin yellow and sunset yellow was observed. More importantly, the catalysts could be recovered readily, and reused many times with good stability. Therefore, the robust material utilized for the treatment of containing organic dyes could be used widely for environmental applications. © 2018 the Partner Organisations.

One of the key challenges in artificial photosynthesis is to design a photocatalyst that can bind and activate the CO2 molecule with the smallest possible activation energy and produce selective hydrocarbon products. In this contribution, a combined experimental and computational study on Ni-nanocluster loaded black TiO2 (Ni/TiO2[Vo]) with built-in dual active sites for selective photocatalytic CO2 conversion is reported. The findings reveal that the synergistic effects of deliberately induced Ni nanoclusters and oxygen vacancies provide (1) energetically stable CO2 binding sites with the lowest activation energy (0.08 eV), (2) highly reactive sites, (3) a fast electron transfer pathway, and (4) enhanced light harvesting by lowering the bandgap. The Ni/TiO2[Vo] photocatalyst has demonstrated highly selective and enhanced photocatalytic activity of more than 18 times higher solar fuel production than the commercial TiO2 (P-25). An insight into the mechanisms of interfacial charge transfer and product formation is explored.