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Abstract To further enhance electrochemical performance of WS 2 -based materials in supercapacitors, a 3D architecture with WS 2 nanoflakes interconnected and quantum dots anchored on N and S co-doped reduced graphene oxide (WS 2 /N,S-rGO) crumpled nanosheets is fabricated for the first time via a novel, facile and scalable approach, which is based on rapid solution combustion synthesis of the precursor and subsequent gas-solid phase sulfurization, and needs no such tedious processes as filtration, washing and drying. Significantly, the WS 2 /N,S-rGO hybrid possesses a specific capacitance of 1562.5 F g−1 at 1 A g−1 and a rate capability of 780 F g−1at 40 A g−1, which are superior to the currently-reported WS 2 -based electrode materials. As to the WS 2 /N,S-rGO hybrid, the 3D hierarchical architecture, synergistic effect between WS 2 and N,S-rGO nanosheets as well as nitrogen and sulfur co-doping on rGO offer a variety of advantages such as larger contact surface area, shorter ion diffusion path, excellent charge transport and especially the enhanced pseudo-capacitance of rGO, and thus result in huge improvement in electrochemical activity, which demonstrate the WS 2 /N,S-rGO hybrid to be a superb anode material in supercapacitors. Graphical abstract 3D WS 2 /N,S-rGO hybrid with superior performance in supercapacitor was fabricated for the first time via a facile and scalable approach based on solution combustion and subsequent sulfurization. Unlabelled Image Highlights • 3D hybrids of WS 2 /N,S co-doped reduced graphene oxide (rGO) are fabricated for the first time. • The synthetic route is based on two steps of solution combustion and sulfurization. • WS 2 nanoflakes and QDs are interlinked with N,S-rGO sheets to form a 3D structure. • The hybrids exhibit a high specific capacitance of 1562.5 F g−1 at 1 A g−1 in SCs. • An excellent rate capability of 780 F g−1at 40 A g−1 is achieved when used in SCs. [ABSTRACT FROM AUTHOR]

The spontaneous stacking of graphene oxide (GO) nanosheets for the adsorptive remediation of wastewater has been severely restricting their inherent adsorption ability from being brought into full play. Herein, hydrosols of carbon nanotubes/graphene oxide (CNTs/GO) sealed in dialysis bags were utilized for the highly efficient and re-pollution-free removal of trace Gd(III) from water for the first time. The effects of mass ratio between CNTs and GO (M CNTs : M GO ), pH value and contact time on Gd(III) adsorption of CNTs/GO hybrid hydrosol (M CNTs : M GO  = 1:6) as well as its adsorption kinetics and thermodynamics were studied by comparison with GO hydrosol. The pH-dependent desorption and regeneration of the CNTs/GO hybrid hydrosol were also investigated. The results showed that CNTs/GO hybrid hydrosols with M CNTs : M GO from 1:8 to 1:2 exhibited the remarkable synergistic enhancement effect. The CNTs/GO hybrid hydrosol with M CNTs : M GO  = 1:6 had the theoretical maximum Gd(III) adsorption capacity of 534.76 mg·g −1 (pH = 5.9, t  = 60 min, T  = 303 K) with a leap of 86.42% compared to GO and remained the sorption capacity of 347.83 mg·g −1 at the fourth cycle, showing the excellent regeneration performance. Moreover, the adsorption of Gd(III) on CNTs/GO hybrid hydrosols agreed well with the pseudo-second-order model and Langmuir isotherm adsorption model. In prospect, CNTs/GO hybrid hydrosols in dialysis bags promises of extensive application in the highly efficient and re-pollution free elimination of metal ions from water. [ABSTRACT FROM AUTHOR]

In this work, presented is a novel and facile strategy to enhance Pb(II) adsorption capacity of graphene oxide (GO) hydrosols via the modified Hummers’ method, using the smaller-sized natural flake graphite as starting materials. The as-prepared micron GO (MGO) and submicron GO (SMGO) hydrosols were sealed in dialysis bags for adsorptive separation of Pb(II) from water to avoid secondary pollution. The effects of pH and contact duration on Pb(II) adsorption on MGO and SMGO as well as their thermodynamics and kinetics were investigated comparatively. Their performances for recycling and regeneration were also evaluated. The results indicated that SMGO exhibited an enhanced maximum sorption capacity for Pb(II) up to 1162.60 mg·g −1 higher than MGO by 25.75% and achieved adsorption equilibrium faster, which can be attributed to the fact that SMGO has more oxygen-containing functional groups on the sheet basal planes and especially at the sheet edges than SMGO. The adsorption of Pb(II) on MGO and SMGO was a spontaneous and endothermic process and well fitted the pseudo-second-order kinetics and the Langmuir sorption model. Significantly, MGO and SMGO nanosheets still kept the high sorption capacities of 514.26 mg·g −1 and 700.35 mg·g −1 after the 5 cycles, respectively, promising of enormous potential applications. [ABSTRACT FROM AUTHOR]