Amorphous, mixed-valency, molybdenum sulfide (MoS x ) with a proposed formula, [Mo(IV) 4Mo(V) 2(S2 2–)3(S2–)5]­(SO4)5, was grown through a one-pot, solvothermal synthesis on multi-walled carbon nanotubes (MWCNTs) in a gram-scale setup. Optimizing the loading of the active catalyst relative to the conductive support resulted in optimized catalytic performance in hydrogen evolution reaction, reaching down to one of the lowest reported overpotentials, η10 = 140 mV and η100 = 198 mV with a Tafel slope of 62 mV/dec, for the 6.5 wt % of MoS x @MWCNTs. Engineering this amorphous MoS x catalyst was made possible through control of the oxidation state of Mo to avoid the fully reduced MoS2 phases. We also demonstrate that engineering defects in the MoS x catalyst does not require sophisticated techniques (e.g., UHV deposition, ion beam sputtering, and pulsed laser ablation) but can rather be induced simply through controlling the reductive synthesis conditions.

a b s t r a c tHydrogels based on sodium alginate and poly(4-vinylpyridine) were successfully prepared via physical cross-linking by ionic interaction. Different hydrogels with different percentages of gelation were prepared by varying the molar ratio between sodium alginate and poly(4-vinylpyridine). The prepared hydrogels were characterized using different techniques as FT-IR spectroscopy, X-ray diffraction (XRD), thermal gravimetric analyses (TGA) and scanning electron microscope (SEM). Increasing of initial decomposition temperature of alginate due to interaction with poly(4-vinylpyridine) was observed. Industrial wastewater mainly contains toxic heavy metal ions and/or dyes (acidic and cationic). In the current study, the removal of heavy metal ions and dyes are studied. Moreover, the behaviors of prepared hydrogels in different buffer solutions were determined. The results show that degree of swelling (DS) is increasing with the increase in the content of poly(4-vinyl pyridine) in the hydrogels. This increasing in DS is much more pronounced in acidic pH than neutral and alkaline pH. The presence of poly(4-vinyl pyridine) in the hydrogels increases the metal ions adsorption as compared with calcium alginate based hydrogel in the ordering Cr 6+ > Cu 2+ > Ni 2+ > Cd 2+ . Hydrogels based on poly(4-vinylpyridne) improves acidic dye uptake as compared to hydrogel based on calcium alginate.

A facile and potentially transferrable approach to enhance the PANI specific capacitance through the incorporation of MOF nanocrystals, as a microporous filler (nanogens), into the PANI matrix to provide ion-diffusion channels within the matrix.

Herein, we present the utilization of Ni2+-doped amine-functionalized UiO-66-NH2 metal-organic framework (MOF) nanoparticles deposited onto multi-walled carbon nanotubes (MWCNTs) as a precursor for electrocatalytically active catalyst towards methanol (MeOH) oxidation. The electrode material displayed an onset potential of 0.42 V (vs Hg/HgO) with maximum activity at 1 M MeOH concentration (143 mA.cm− 2 current density at 0.6 V vs Hg/HgO). The catalyst also demonstrated adequate stability, where 93.5% of its current density was retained after performing chronoamperometry for 1 hr.

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