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Pt-based bimetallic alloys have attracted intensive interests as highly efficient and stable heterogeneous catalysts for fuel cell applications, and searching flexible free-standing nanomembranes has been on the research focus because of their promising applications in catalysis, nanoelectronics, batteries, and sensing. Herein, a flexible free-standing paper composed of FePt alloy nanoparticles on nitrogen-doped paper (FePt-NG paper) has been developed as integrated electrode towards electrocatalytic oxidation of formic acid. It is found that, N doping is beneficial for the well dispersion of FePt nanoparticles on NG paper. The synergistic effect between Fe and Pt, as well as N doping effect simultaneously assures the improved catalytic activity of FePt-NG paper, making it the promising flexible electrode for application in fuel cell system. Moreover, the synthesis strategy could be used for the construction of other free-standing electrode towards catalysis, sensing, and battery applications. Graphical Abstract: [ABSTRACT FROM AUTHOR]

Porous frameworks with geometry nanostructures have attracted increasing research interest due to their specific architectures which offer structural advantages for energy conversion and storage. Here, we firstly report the synthesis of porous cubes constructed by hybrid SnO 2 -CoS nanoparticles using cubic CoSn(OH) 6 precursor as template. The porous nanostructures, nanosized subunits, as well as the cubic geometry feature offer abundant pores and channels for electrolyte diffusion, ensure large contact surface area between electrolytes and active materials, shorten transport distance of lithium ion, and supply voids to buffer the huge volume variation, making it an ideal candidate for reversible lithium storage. When used as anode material for lithium-ion batteries (LIBs), the developed sample exhibits outstanding electrochemical properties of large reversible capacity, high rate capability, and stable durability (750 mAh g −1 at 100 mA g −1 after 100 cycles). [ABSTRACT FROM AUTHOR]

Highlights: [•] FePt alloy nanoparticles anchored RGO composites are successfully synthesized. [•] The alloying of Fe with Pt is demonstrated with XRD and elemental maps. [•] FePt/RGO show enhanced catalytic activity on FA/methanol oxidation than Pt/RGO. [•] FePt/RGO also exhibit improved tolerance to CO poisoning than Pt/RGO. [Copyright &y& Elsevier]

[Display omitted] • Sulfur on CoFe alloys embedded in nitrogen-doped carbon nanosheets is designed. • M−S n 2- is the robust catalysis sites for HER. • The synergisms between sulfur and CoFe@NC are beneficial for HER. • 2D NC interacted 3D network supplies easily accessible active sites and rapid charge transfer. • The present S-CoFe@NC exhibits Pt-like HER performance in neutral media. Seeking novel low-cost non-noble metal based electrocatalysts with high efficiency is of great significance to promote industrial application of hydrogen evolution reaction (HER). Herein, we originally demonstrate sulfur on CoFe alloys embedded in nitrogen-doped carbon nanosheets (S-CoFe@NC) catalyst with extremely robust HER activity in neutral media. The present sample exhibits active HER performance with ultralow overpotential of 37 mV at current density of 10 mA cm−2 and Tafel slope of 34 mV dec-1, which is the same as commercial Pt/C. Systemic studies show that strong interaction between bridging S n 2- and CoFe@NC introduces M−S n 2- as the robust catalysis sites for HER, which is also beneficial for the charge exchange. The specific structure of NC nanosheet interconnected network provides structure advantages for easily accessible active sites and fast charge transfer for electrocatalysis. Thus, this work paves a way for the development of new class of sulfur based electrocatalyst with efficient HER performance for neutral water splitting. [ABSTRACT FROM AUTHOR]

• S, N co-doped carbon nanosheets are prepared as SIBs anode. • S, N co-doping endows enlarged interlamellar spacing and defective active sites for improved sodium storage. • S, N co-doping improves Na+ diffusion coefficient. • High capacity of 270 mAh g−1 is obtained at 0.1 A g−1 after 100 cycles. • Capacity of 100 mAh g−1 is achieved at high rate of 1 A g−1 after long-term 1000 cycles. Heteroatom doping into specific nanostructure is believed as the leading solution for developing the advanced carbon materials for sodium ion batteries (SIBs), however, the preparation and understanding of heteroatoms co-doped carbon anodes are still challenging. Herein, the sulfur and nitrogen co-doped (weight content of 15.64% for N and 3.1% for S) carbon nanosheets (SNC) are prepared by treating nitrogen-rich carbon nanosheets with sublimation sulfur. The S, N co-doping is responsible for the enlarged interlamellar spacing of 0.38 nm and abundant defect-introduced active sites. These structure features combined with the advantage of nanosheet are significant for activating sodium ion storage properties, endowing SNC with high Na+ storage capacity of 270 mAh g−1 at 0.1 A g−1 and 100 mAh g−1 at 1 A g−1 after 1000 cycles. More importantly, the kinetic analysis is carried out to illustrate that S, N co-doping can improve the Na+ diffusion coefficient in carbon anode and enhance the ion storage. This work deepens the understanding on the boosting effect of heteroatoms dual-doping for the sodium ion storage of carbon materials, which conduces to development of advanced heteroatom doped carbon anodes for SIBs. [ABSTRACT FROM AUTHOR]

Rational design and constructing advanced materials with intriguing nanostructures towards highly efficient and sustainable energy conversion and storage have received focused research efforts, but exploring effective strategies to accomplish this mission is still challenging. Aiming at this goal, we construct MoS 2 nanosheets on Fe 3 O 4 nanospheres via a SiO 2 shell assisted sacrifice template method for the first time. The shell-core structured MoS 2 @Fe 3 O 4 catalyst is well characterized by XRD, Raman, TEM, SEM, and XPS techniques. SEM and TEM show that MoS 2 nanosheets possess edge exposed feature and defect-rich structure, assuring the maximum active sites for electrochemical hydrogen evolution reaction (HER). Raman characterization reveals the chemical coupling between MoS 2 and Fe 3 O 4 , indicating the formation of MoS 2 @Fe 3 O 4 heterostructure at the shell-core interface. High-resolution TEM (HRTEM) shows abundant defects at the heterostructures, which supplies more catalytic sites. The improved catalytic sites are proved by electrochemical capacitance measurements, and the enhanced catalytic activity over each site is also probed. Therefore, MoS 2 @Fe 3 O 4 exhibits remarkably enhanced catalytic activity for water splitting due to the above mentioned benefits. [ABSTRACT FROM AUTHOR]

Exploration of novel advanced materials for energy conversion and storage is on the research focus. Herein, we firstly develop FeMo 4 S 6 nanosheets via a hydrothermal process as advanced energy materials. TEM and XRD characterizations reveal that FeMo 4 S 6 nanosheets possess distinctive layered structure with an interlayer distance of 0.64 nm and 10–14 layers in thickness. Rooted in the intriguing layered 2D structural advantages and multicomponent effect, the sample exhibits large and stable lithium storage properties when it is used as anode material for lithium-ion batteries. It is also evaluated as electrocatalyst for water splitting and shows promising catalytic activity for hydrogen evolution, including low onset overpotential and stable cycling durability. [ABSTRACT FROM AUTHOR]

MoS 2 has emerged as an efficient hydrogen evolution catalyst and its activity is believed to be mainly determined by two factors: the amount of edge sites and electrical conductivity. To achieve improved catalytic activity, the few-layered oxygen-incorporated MoS 2 ultrathin nanosheets are prepared for the construction of hybrid nanosheets with graphene substrates using one-pot hydrothermal method for the first time. XRD, Raman, SEM, TEM, EDS and TGA techniques are used to characterize the hybrids. The moderate oxygen-incorporation into MoS 2 creates abundant edge sites and improves the conductivity. The tight coupling between the hybrid nanosheets expedites the electrical transfer. Endowed with the above advantages, the hybrid nanosheets are ideal electrocatalysts for hydrogen evolution reaction (HER) and exhibit high activity, which is demonstrated by the ultralow onset overpotential (120 mV), large cathodic current density (65.5 mA cm −2 at η = 300 mV), and small Tafel slope (51 mV decade −1 ), as well as superior cycling stability. Our enhanced understanding of this highly active MoS 2 hybrid catalyst for HER may facilitate the development of economical electrochemical hydrogen production systems. [ABSTRACT FROM AUTHOR]

A layer-by-layer assembled composite of graphene nanosheets (GNSs) wrapped monodisperse cobalt sulfides (CoS 2 ) nanocages has been prepared via a solvothermal method. The flexible GNSs in the layered composite act as the effective matrix to encapsulate the monodisperse CoS 2 nanocages, buffer the volume changes and prevent the aggregation of the CoS 2 nanocages during electrochemical cycling. The loosely stacked GNSs, which are induced with the insertion of CoS 2 , are convenient for electrolyte wetting and serve as highway for the rapid electron and lithium transport. The monodisperse nanocages can supply additional space to tolerate the volume changes, shorten lithium diffusion path, and do not tend to aggregate. As a result, the specific sample can deliver a high capacity approaching 800 mA h g −1 after 150 cycles at 100 mA g −1 and 697 mA h g −1 after 300 cycles at 500 mA g −1 , in addition to good capacity retention and excellent rate capability, making it a promising candidate as next-generation anode materials for lithium-ion batteries. [ABSTRACT FROM AUTHOR]