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A three dimensional (3D) reduced graphene oxide (rGO)/zeolitic imidazolate framework-67(ZIF-67) aerogel (3D rGO/ZIF-67 aerogel) was prepared via in situ assembly of ZIF-67 polyhedrons on a 3D rGO networks, not only providing multifarious affinity interactions for synergistic promoting the adsorption behavior of organic dyes, but also constructing a holder for ZIF-67 polyhedrons to convenient separation. This porous aerogel displays excellent absorption ability for cationic dyes (crystal violet, CV) and anionic dyes (methyl orange, MO). The maximum adsorption capacities are up to 1714.2 mg·g −1 and 426.3 mg·g −1 for CV and MO, respectively. 3D rGO/ZIF-67 aerogel shows a remarkable promoting of CV adsorption capacity than pure 3D rGO and ZIF-67. The ultrahigh adsorption capability towards cationic CV dyes is mainly driven by π-π interactions and electrostatic interactions between 3D rGO/ZIF-67 aerogel and dye molecules, and synergistic interactions at the interface of 3D rGO and ZIF-67 polyhedrons. The high adsorption capability towards anionic MO dyes is mainly due to the porosity of ZIF-67 polyhedrons and electrostatic attraction between MO and ZIF-67. The multi-component property of 3D rGO/ZIF-67 aerogel shows a great potential application in dye-bearing wastewater treatment. [ABSTRACT FROM AUTHOR]

Efficacious and convenient removal of organic dye contaminants from wastewater is a challenge for public health and ecosystem protection. Here we fabricate a novel type of Fe 3 O 4 @MOFs (Metal-organic frameworks) magnetic porous composite materials. ZIF-67 (Zeolitic imidazolate framework-67) nano-crystals as an attractive subfamily of MOF was selected to fabricate Fe 3 O 4 -PSS@ZIF-67 composites (defined as MZIF-67). MZIF-67 composites are core-shell structure, for which the aggregation core of Fe 3 O 4 nanoparticles is coated with petal-like ZIF-67 crystals, in which Co 2+ firstly combines with SO 3 2− provided by PSS (poly (styrenesulfonate, sodium salt)) to form nucleation. MZIF-67 composites perform well on methyl orange (MO) adsorption, which could be attributed to the highly porosity and the nature of Lewis base of coordinated Co 2+ centrals. The results show that the equilibrium adsorption capacity for MO is up to 738 mg·g −1 (when pH = 8.0, contact time is 7 h, adsorbent dose is 5 mg and initial MO concentration is 400 mg·L −1 ). In addition, MZIF-67 composites could selectively separate MO from the mixture solution of MO and MB (methylene blue). The removal rate of MO is up to 92%. The concentration ratio of MO/MB is 0.04. And the separation efficiency is up to 96%. The results suggest MZIF-67 composites could be a good candidate for treatment of dye-bearing wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • An all-in-one MoS 2 -based electrocatalyst for hydrogen evolution is constructed by inkjet printing. • Inkjet-printed 3D architecture contributes to the exposure of active catalytic sites. • 1T-MoS 2 surrounded by graphene reduces the charge-transfer impendence. • Cu contact supports the efficient electron injection from the electrode to catalytic materials. • The facile and scalable avenue allows the fabrication of electrocatalysts with high throughput. 2D transition metal dichalcogenides (TMDs) are emerging as promising alternative electrocatalysts for hydrogen evolution reaction (HER). However, key challenges are the limited density of available activity sites and poor electron accessibility. Herein, Cu film supported MoS 2 -based electrocatalyst with partial 1T phase and 3D architecture is constructed by inkjet printing. We aim to investigate if this configuration could provide largely exposed edge sites and enhance electron transfer for ultra-efficient hydrogen production. Towards this end, an ink containing few-layer MoS 2 nanosheets and reduced graphene oxide (RGO) is firstly prepared by liquid-phase exfoliation, in which semiconducting 2H-MoS 2 is partially transformed to metallic 1 T-MoS 2. We demonstrate that 1) nanosized few-layer MoS 2 spatially patterned by inkjet-printing provides sufficient active site exposure, 2) the 1T-MoS 2 and RGO conductive network reduce the charge-transfer impedance, and 3) the Cu support enhances the catalyst-electrode charge injection. Our all-in-one structure exhibits outstanding HER activities with low overpotential (51 mV at 10 mA cm−2 and 126 mV at 100 mA cm−2) and very low Tafel slope (32 mV dec-1). Also, the as-engineered electrode demonstrates ultrahigh cathodic current density. This work provides a facile, inexpensive, and scalable way for designing and fabricating TMDs-based electrocatalysts with excellent HER activity. [ABSTRACT FROM AUTHOR]