Graphene nanoribbons (GNRs) derived from the unzipping of carbon nanotubes are used as a catalyst carrier for MoS2 with different layers via a facile solution route. Efficient hydrodesulfurization (HDS) of carbonyl sulfide (COS) has been achieved over the MoS2/GNR composites. It is revealed that single layer MoS2 anchored on GNRs (SL-MoS2/GNRs) is successfully fabricated by the assistance of cetyltrimethylammonium bromide (CTAB). The catalytic activities of the SL-MoS2/GNRs, few-layer MoS2 supported on GNRs (FL-MoS2/GNRs) and pure MoS2 with a multi-layer structure (ML-MoS2) are investigated, and the layer-dependent catalytic activity of MoS2 has been demonstrated in the hydrogenation of COS. The order of the catalytic performance for the three catalysts is SL-MoS2/GNRs > FL-MoS2/GNRs > ML-MoS2, especially within a low temperature range (180–280 °C) of the HDS reaction. The superior catalytic activity of SL-MoS2/GNRs can be ascribed to the high density of the active sites in single-layer MoS2. Due to the edge effect of GNRs, single layer MoS2 supported on GNRs is thinner and shorter than MoS2 anchored on graphene nanosheets (GS). The synergy between single layer MoS2 and GNRs may be mainly responsible for the better catalytic performance of SL-MoS2/GNRs. This work offers a feasible strategy for the synthesis of single-layer MoS2 supported on GNRs for efficient HDS application.

•Highly dispersed monolayer MoS2/RGO (ML-MoS2/RGO) catalyst has been prepared.•ML-MoS2/RGO shows high catalytic activity for the HDS of COS at low temperature.•Layer-depended catalytic performance of MoS2 active component has been demonstrated.Highly active monolayer MoS2/reduced graphene oxide (ML-MoS2/RGO) catalysts have been fabricated with the assistance of cetyltrimethylammonium bromide via a solution route. The as-prepared catalysts are systematically investigated by X-ray diffraction, Raman spectra, field emission scanning electron microscopy and high-resolution transmission electron microscopy. Layer-depended catalytic performance of MoS2 active component has been demonstrated in the model hydrodesulfurization reaction of carbonyl sulfide. The ML-MoS2/RGO composites show superior catalytic activity compared with few-layer MoS2/RGO (FL-MoS2/RGO) catalyst or bulk MoS2 with multilayer structure, which can be ascribed to more exposure of MoS2 active sites on monolayer MoS2 combined with high dispersion of monolayer MoS2 nanoparticles on RGO sheets. This work offers a facile strategy for the synthesis of monolayer MoS2 supported on RGO for efficient catalysis applications.Download high-res image (307KB)Download full-size image

Nitrogen-doped graphene nanoribbon aerogels (N-GNRAs) are fabricated through the self-assembly of graphene oxide nanoribbons (GONRs) combined with a thermal annealing process. Amino-groups are grafted to the surface of graphene nanoribbons (GNRs) by an epoxy ring-opening reaction. High nitrogen doping level (7.6 atm% as confirmed by elemental analysis) is achieved during thermal treatment resulting from functionalization and the rich edge structures of GNRs. The three dimensional (3D) N-GNRAs feature a hierarchical porous structure. The quasi-one dimensional (1D) GNRs act as the building blocks for the construction of fishnet-like GNR sheets, which further create 3D frameworks with micrometer-scale pores. The edge effect of GNRs combined with nitrogen doping and porosity give rise to good electrical conductivity, superhydrophilic, highly compressible and low density GNRAs. As a result, a high capacity of 910 mA h g−1 is achieved at a current density of 0.5 A g−1 when they are tested as anode materials for lithium ion batteries. Further cell culture experiments with the GNRAs as human medulloblastoma DAOY cell scaffolds demonstrate their good biocompatibility, inferring potential applications in the biomedical field.

Interlayer expanded MoS2 grown on graphene nanoribbon aerogel (GNRA) has been synthesized and used as anode material for high performance lithium and sodium ion batteries (LIBs, SIBs). The edge effect of graphene nanoribbons including the enormous oxygen functional groups and the insertion of edge carbon layers leads to the formation of MoS2 with large interlayer spacing. The expansion boosts the intercalation and diffusion of alkaline ions (Li+ and Na+) in layered MoS2. As tested for LIBs, the MoS2/GNRA electrodes exhibit excellent rate performance as capacity of 303 mAh g−1 can still be achieved even at a high current density of 30 A g−1. Long cycling performance for 1800 cycles at 10 A g−1 further confirms their superior stability. The hybrid structures also show good performance for SIBs, specific capacities of 372–203 mAh g−1 are obtained at a current density range of 0.5–15 A g−1. A capacity of 158 mAh g−1 is still kept even after 1500 cycles at 5 A g−1. This work provides a facile method to control the structure of layered metal sulfides and confirms their potential applications in energy storage and conversion.

A series of nitrogen-doped mesoporous carbons (NMCs) were prepared using Pluronic F127 as a structure directing agent, phloroglucinol and formaldehyde as carbon precursor and dicyandiamide as nitrogen source. The obtained nitrogen-doped mesoporous carbons possess high nitrogen content of 6.37–19.28 wt%. Due to the feature of high nitrogen contents, NMCs show superior H2S adsorption performance with breakthrough sulfur capacity of 0.48 mmol g−1 at room temperature and ambient pressure. It is revealed that in addition to the nitrogen content, nitrogen configuration and porosity of the carbon materials also influence significantly their sulfur capacity. This work offers a facile strategy for the synthesis of porous carbon materials with excellent performance in the adsorptive removal of H2S.

Nitrogen-doped graphene nanoribbons (N-GNRs) were synthesized through longitudinal unzipping of nitrogen-doped carbon nanotubes filled with iron nanowires (Fe@CNx-CNTs) by means of nitric acid oxidation. Benefiting from their N doping and edge effect, N-GNRs showed high capacity, excellent cycling performance and rate capability as anode materials in lithium ion batteries (LIBs).

In this work, a novel strategy to obtain the graphene-supported palladium catalyst for the hydrodesulfurization of carbonyl sulfide (COS) in coal gas is presented. By employing the low temperature dielectric barrier discharge (DBD) plasma, well-dispersed Pd nanoparticles with particle size of about 2 nm supported on graphene sheets (PL-Pd/GS) have been synthesized through a facile one-step route, in which the graphite oxides and PdCl2 were simultaneously reduced in hydrogen plasma. The as-prepared PL-Pd/GS catalyst shows higher catalytic efficiency in the COS hydrogenation, compared to a traditional Pd/C catalyst, as well as Pd/GS reduced by hydrogen at high temperature or by ethylene glycol reduction in liquid phase. Characterizations using XRD, FT-IR, Raman, and HRTEM techniques reveal that the improved performance of PL-Pd/GS for COS conversion is attributed to small size and uniform dispersion of Pd nanoparticles on graphene sheets resulting from the efficient low temperature treatment in DBD plasma. This finding inspires the in situ preparation of various metal–graphene sheets catalysts by taking advantage of plasma, and paves a new avenue to make use of graphene sheets as a support material to improve catalytic activity.

In this work, we report a novel synthesis of two-dimensional (2D) N-doped mesoporous carbon nanosheets (NMCS) with high nitrogen content and developed porosity from microporous Zn-based zeolitic imidazolate framework (ZIF-8) polyhedrons in a molten salt medium. The ZIF precursors allow high nitrogen content of the NMCS while the molten salt medium leads to the formation of 2D nanosheets with mesoporosity during the pyrolysis process. The obtained NMCS exhibit highly catalytic activity in the metal-free catalytic oxidation of H2S toward elemental sulfur at room temperature, high breakthrough sulfur capacity is achieved over NMCS, much superior to that of ZIF-8 derived N-doped porous carbons obtained by direct pyrolysis. The transformation of three-dimensional ZIF-8 into nitrogen-doped 2D carbon nanosheets via molten salt media has great potential for the large-scale and green production of porous carbon nanosheets for highly efficient desulfurization and energy storage-conversion.

In this study, hydrogenation of carbonyl sulfide (COS) has been investigated over nano-catalyst derived from single-crystalline Co3O4 nanocrystals with different morphology. Co3O4 nanocrystals, i.e. nanorods and nanopolyhedra, are synthesized by a facile ethylene glycol route and subsequent thermal process. After in situ presulfidation, hydrodesulfurization (HDS) of COS is conducted on these unsupported catalysts in the temperature range of 150–300 °C. Compared with the sulfided nanopolyhedra, the catalytic activity of the sulfided nanorods is much higher especially at low temperature of 200 °C. Surface areas, crystalline phase and particle size distributions of the nanocrystals are determined by Brunauer–Emmet–Teller method, X-ray diffraction and transmission electron microscopy, respectively. It is shown that the catalytic properties of the as-prepared nanocrystals are dependent on the nature of their surface structure, and the crystal plane of Co3O4 plays an important role in determining its degree and easiness of presulfurization and consequently HDS performance for COS. The shape-controlled synthesis of nanocrystals may be an effective means for promoting reactive activities for HDS catalysts.Graphical abstract.Download high-res image (110KB)Download full-size imageHighlights► Co3O4 nanocrystals with controllable shape are synthesized by the Ref's method. ► Hydrogenation activity of carbonyl sulfide (COS) is studied over sulfided Co3O4. ► The catalytic property of COS depends on the shape of unsupported sulfided Co3O4. ► Sulfided Co3O4 nanorods is superior to nanopolyhedra for the hydrogenation of COS.

Nitrogen-doped graphene nanoribbons (N-GNRs) were synthesized through longitudinal unzipping of nitrogen-doped carbon nanotubes filled with iron nanowires (Fe@CNx-CNTs) by means of nitric acid oxidation. Benefiting from their N doping and edge effect, N-GNRs showed high capacity, excellent cycling performance and rate capability as anode materials in lithium ion batteries (LIBs).

Graphene nanoribbons (GNRs) derived from the unzipping of carbon nanotubes are used as a catalyst carrier for MoS2 with different layers via a facile solution route. Efficient hydrodesulfurization (HDS) of carbonyl sulfide (COS) has been achieved over the MoS2/GNR composites. It is revealed that single layer MoS2 anchored on GNRs (SL-MoS2/GNRs) is successfully fabricated by the assistance of cetyltrimethylammonium bromide (CTAB). The catalytic activities of the SL-MoS2/GNRs, few-layer MoS2 supported on GNRs (FL-MoS2/GNRs) and pure MoS2 with a multi-layer structure (ML-MoS2) are investigated, and the layer-dependent catalytic activity of MoS2 has been demonstrated in the hydrogenation of COS. The order of the catalytic performance for the three catalysts is SL-MoS2/GNRs > FL-MoS2/GNRs > ML-MoS2, especially within a low temperature range (180–280 °C) of the HDS reaction. The superior catalytic activity of SL-MoS2/GNRs can be ascribed to the high density of the active sites in single-layer MoS2. Due to the edge effect of GNRs, single layer MoS2 supported on GNRs is thinner and shorter than MoS2 anchored on graphene nanosheets (GS). The synergy between single layer MoS2 and GNRs may be mainly responsible for the better catalytic performance of SL-MoS2/GNRs. This work offers a feasible strategy for the synthesis of single-layer MoS2 supported on GNRs for efficient HDS application.

Flexible, interconnected sulfur/reduced graphene oxide nanoribbon paper (S/RGONRP) is synthesized through S2− reduction and evaporation induced self-assembly processes. The in situ formed sulfur atoms chemically bonded with the surface of reduced graphene oxide nanoribbons and were physically trapped by the compact assembly, which make the hybrid a suitable cathode material for lithium–sulfur batteries.