Electrochemical splitting of water to produce hydrogen and oxygen is an important process for many energy storage and conversion devices. Developing efficient, durable, low-cost, and earth-abundant electrocatalysts for the oxygen evolution reaction (OER) is of great urgency. To achieve the rapid synthesis of transition-metal nitride nanostructures and improve their electrocatalytic performance, a new strategy has been developed to convert cobalt oxide precursors into cobalt nitride nanowires through N2 radio frequency plasma treatment. This method requires significantly shorter reaction times (about 1 min) at room temperature compared to conventional high-temperature NH3 annealing which requires a few hours. The plasma treatment significantly enhances the OER activity, as evidenced by a low overpotential of 290 mV to reach a current density of 10 mA cm(-2) , a small Tafel slope, and long-term durability in an alkaline electrolyte.

yields a synergism for the HER. [ 25 ] In accordance with the "volcano plot," the activity for the evolution of hydrogen is a function of the M H (metal hydride) bond strength and exhibits a peak value for metal Pt, which has an optimal M H bond strength. [ 26 ] Therefore, designing a material on the molecular scale which combines an M H-weak metal (Ni) with an M H-strong metal (Mo) is a feasible method to acquire ideal catalysts. Sasaki's group synthesized NiMoN x nanosheets on carbon support [ 21 ] and mixed close-packed Co 0.6 Mo 0.14 N 2 particles [ 20 ] via annealing corresponding precursors under ammonia gas. Both of the materials show the high HER electrocatalytic activity with low overpotential and small Tafel slope. In addition to the pristine activity of the catalysts, a variety of other parameters can limit their performance, such as roughness, conductivity, stability of the catalyst, the attachment of catalysts on electrodes. [ 27 ] In general, hazardous and unfriendly ammonia is applied as nitrogen source for synthesis of metal nitrides from metal oxide precursors at relatively high temperatures (600-800 °C). [ 21,[28][29][30] In addition, this method often results in incomplete nitrifi cation, leading to inferior electronic, mechanical and thermal properties of the as-obtained composites. In this work, we employed a novel method to synthesize 3D porous nickel molybdenum nitride on carbon cloth (NiMoN) by treating electrodeposited NiMo alloy fi lms with N 2 plasma at a relatively low reaction temperature (450 °C) and shorter duration (15 min). The obtained bimetallic nitrides exhibit a 3D porous hierarchical structure with high roughness factor (1050), and outstanding catalytic performance for HER. It is believed that this method can be employed for the synthesis of many other bimetallic nitride nanostructures for applications in battery and supercapacitors.The overall synthesis procedure for the porous NiMoN fi lms on carbon cloth is illustrated schematically in Figure 1 a. First, a dense and shiny grey NiMo alloy fi lm is deposited on commercial carbon cloth (Figure 1 c,f) via optimized pulse-electrodeposition (PED) method. Then, after being treated under N 2 RF plasma at 450 °C for 15 min, a porous and black NiMoN fi lm is obtained (Figure 1 d,g). According to the previous report, [ 31 ] the metal Mo cannot be electroplated from an aqueous solution directly without the assistant of metal Ni. With increasing the molybdenum content, the deposited alloys tend to the amorphous state and an amorphous pattern appears when the content of molybdenum is over 20 at%. [ 32 ] A further increase in the molybdenum content causes crack in the deposited fi lm. Hence, a molybdenum concentration of 20 at% in the alloy is found optimal by tuning the deposition parameters (Supporting The fossil-fuel crisis and the increasing environment issues have triggered the urgent demand for renewable and clean energy sources. Hydrogen is considered as a promising alternative energy carrier to fossil fuels because of its zero ca...

Details of a fast and sustainable bottom-up process to grow large area high quality graphene films without the aid of any catalyst are reported in this paper. We used Melaleuca alternifolia, a volatile natural extract from tea tree plant as the precursor. The as-fabricated graphene films yielded a stable contact angle of 135°, indicating their potential application in very high hydrophobic coatings. The electronic devices formed by sandwiching pentacene between graphene and aluminum films demonstrated memristive behavior, and hence, these graphene films could find use in nonvolatile memory devices also.

limited space becomes a critical parameter. The conventional carbo naceous anodes are limited by their relatively low sodium storage capacity. [1,2] Recently, alloying-type anodes, such as Sb nanorod, [3] SnS nanohoneycomb, [4] SnO nanosheet, [5] and branched SnS 2 , [6] have been extensively reported to possess enhanced sodium-ion gravimetric, areal, and volumetric storage capacities. But the cycling stability is still a major bottleneck.Great efforts have been dedicated to improving the cycling stability of the battery electrodes, particularly alloy-type materials. A well-defined conductive network is essential to accommodate the large volume change, stabilize the structure, and supply conductive channels. [7][8][9] Current research has shown that the combination of graphene, or more commonly, reduced graphene oxide (rGO), with metal oxides, sulfides, and metal alloys can significantly enhance the sodium storage performance. [8,[10][11][12][13][14] For instance, Yu et al. reported that Sb 2 S 3 /graphene composite gave a high capacity of 730 mAh g −1 and a stable charge/ discharge performance in 50 cycles. [15] SnS 2 /graphene [16] and SnS/graphene [17] nanosheets prepared by hydrothermal method with graphene oxide showed a high reversible capacity of 940 mAh g −1 at 0.03 A g −1 with 250 cycles at 7.29 A g −1 and 630 mAh g −1 at 0.2 A g −1 with 400 cycles at 1.0 A g −1 , respectively. In another work, SnO 2 /SnS/graphene heterostructure [18] delivered 729 mAh g −1 at 0.03 A g −1 with enhanced cycling stability of 500 cycles at 2.43 A g −1 . However, these laminate structures inevitably introduce excess exposure of active materials to the electrolyte, which will form thick solid-state electrolyte interface (SEI), aggregate and detach gradually from the graphene surface. Regrettably, this counters the attempt to obtain long-term cycling life with maintained high capacity.It remains a big challenge to in situ grow robust graphene onto everywhere of active material nanoarchitectures, especially for the alloying-type electrode materials.In this work, we develop a facile and rapid C-plasma strategy to in situ generate robust hierarchical graphene (hG) bundled onto tin sulfide networks to stabilize its long-cycle capacity for reversible Na-ion storage. This also illustrates that tin is applied as catalyst for the growth of graphene (growth mechanism is supported by density functional theory calculations). In contrast to the conventional laminate graphene composite structure, chemical-bonded hG provides continuous and permanently Tin and its derivatives have provoked tremendous progress of high-capacity sodium-ion anode materials. However, achieving high areal and volumetric capability with maintained long-term stability in a single electrode remains challenging. Here, an elegant and versatile strategy is developed to significantly extend the lifespan and rate capability of tin sulfide nanobelt electrodes while maintaining high areal and volumetric capacities. In this strategy, in situ bundles of robust hierarchical gr...

Developing transition metal nitrides with unique nanomorphology is important for many energy storage and conversion processes. Here, a facile and novel one‐step approach of growing 3D hierarchical nickel nitride (hNi3N) on Ni foam via nitrogen plasma is reported. Different from most conventional chemical synthesis, the hNi3N is obtained in much shorter growth duration (≤15 min) without any hazardous or reactive sources and oxide precursors at a moderate reaction zone temperature of ≤450 °C. Among possible multifunctionalities of the obtained nanocoral hNi3N, herein the performance in reversible lithium ion storage and electrocatalytic oxygen evolution reaction (OER) is demonstrated. The as‐obtained hNi3N delivers a considerable cycling performance and rate stability as a lithium ion battery anode, and its property can be further enhanced by coating the hNi3N surface with graphene quantum dots. The hNi3N also serves as an active OER catalyst with high activity and stability. Additionally, on the basis of controlled growth under different nitrogen plasma treatment time, the formation mechanism of the nanocoralline hNi3N is outlined for further extension to other materials. The results on time‐ and energy‐efficient nitrogen‐plasma‐based preparation of hNi3N pave the way for the development of high‐performance metal nitride electrodes for energy storage and conversion.

N2 plasma induces simultaneous nanoporosity and N-doping in carbon cloth, making it an active electrode for supercapacitors, batteries and probably electrocatalysts.

desirable to modify and functionalize the surface of electrode materials, such as by introducing defects, doping, and with high specific surface areas. For example, carbon materials doped with heteroatoms (N, S, P, etc.) have been extensively applied in energy storage and conversion devices. [9][10][11] In addition, commercialization of these energy devices requires not only good electrochemical performance, but also overall low cost. Therefore, for both synthesis and surface functionalization, it is meaningful to utilize cost-effective and efficient techniques.Plasma, as one of the four fundamental states of matter, consists of charged and neutral particles, in which the positive and negative ions are highly energetic and completely free to move. [12] Therefore ions in plasma show a higher chemical activity than diffusionlimited thermal reactions. [13] Plasma-assisted techniques are becoming powerful tools for nanoscale fabrication and modification, as plasmas provide a complex, reactive, and far-fromequilibrium chemical factory. Reactions that do not proceed easily at low temperatures have become possible with a short duration under a high-energy plasma ambient. Among the various types of plasmas, radio-frequency (RF) plasma systems are commonly utilized because of their energy efficiency, the short treatment duration, and the relatively low reactor-zone temperature. The plasma is produced by gas discharge initiated by RF electromagnetic fields. In this case, the electron temperature can be extremely high (10 4 −10 5 K), which makes the surface reaction very effective.The parameters of the plasma species, e.g., type of ionic particles and their densities, should be monitored and controlled. This is important if one wants to realize surface modification of electrode materials in an atomic depth. Different gas sources result in different plasma treatments, as they have different atomic, molecular, excited, and ionic species, with different densities, due to different dissociation and ionization energies. For example, nitride formation requires atomic nitrogen, which can be obtained from either nitrogen (N 2 ) gas or ammonia (NH 3 ) discharge plasma. The dissociation and ionization energies of ammonia are much lower than those of nitrogen molecules, and, hence, ammonia is preferred for plasma treatment, particularly in low-power plasma discharge. However, at moderate-or high-power plasma discharge, both are equally efficient in providing atomic nitrogen. NH 3 , however, is toxic and provides a wide variety of species in the plasma state, including N, N + , N 2 , H, H 2 , NH, and NH 2 , etc. The availability of NH 2 and H radicals in ammonia plasma may lead to amine Transition-metal compound (nitrides, carbides, phosphides, etc.) nanomaterials are under intensive research as potential advanced electrode materials in batteries, supercapacitors, and electrocatalytic water splitting. The radio-frequency plasma-assisted technique has emerged as a powerful tool in inducing nanoscale reactions, doping, defects, and nanos...

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