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Developing battery-supercapacitor hybrid devices (BSHs) is viewed as an efficient route to shorten the gap between supercapacitors and batteries. In this study, a composite hydrogel consisting of perylene tetracarboxylic diimide (PTCDI) and reduced graphene oxide (rGO) is tested as the anode for BSHs in the electrolyte of ammonium acetate (NH

We report an electrocatalyst, Co bases (metallic Co and Co(OH)2) with fluoride-incorporated CoO coating on the surface of (CoO–F/Co), was synthesized by the electro-deposition method.

In this work, a novel acetamide-based deep eutectic solvent (DES) with Zn

We report a facile method for dispersing Mn species onto two-dimensional Co3O4 nanosheets at the nanoscale for the selective catalytic reduction (SCR) of NOx with NH3. In comparison with the reference catalysts with higher Mn loadings, the Mn/Co3O4 (0.8 wt%) catalyst exhibits improved catalytic activity and a high H2O-resistance ability. Due to the strong interaction between cobalt and manganese oxides and the increased surface area of the Co3O4 nanosheets, the catalyst with an ultralow amount of Mn at the nanoscale possesses stronger reducibility, abundant Co3+ and surface oxygen species, which in turn enhance the NH3-SCR activity.

High-performance aqueous all-organic rechargeable batteries are promising candidates for cost-effective, safe, and environment-friendly next-generation energy storage devices. Herein, two organic copolymers with nanorod-like morphology (AN-TA, and AN-PA), composed of different tertiary amines, are synthesized as the cathode material for an aqueous proton battery. The individual copolymer electrodes possess the dominated diffusion-controlled electrode kinetics resulting from the proton insertion/de-insertion along with the surface-controlled processes in 2 M HCl and 2 M H

In this work, a catalyst of graphene oxide supported CeO2 (referred to as CeO2/GO) is prepared and characterized by TEM, H2-TPR, NH3-TPD and XPS. The catalytic tests show a NO conversion of 97% at ...

Composite materials with carbon nanotubes (CNTs) and graphene oxide (GO) are considered to be superior for energy storage applications due to their intriguing structural and electrical properties. The electrochemical performance of CNT/GO-based electrodes can be improved by introducing porous carbon materials into them. Herein, we have carbonized the composite consisted of polyaniline (PANI), GO and CNTs on stainless steel plates and investigated their electrochemical performances as a free-standing and binder-free electrode for supercapacitors. The carbonized PANI with a coral-like nanostructure was formed over CNT and GO surface. Furthermore, the introduction of GO efficiently prevents the excessive agglomeration of PANI in the resultant composite materials. The carbonized composite electrode exhibited the high specific capacitance of 465 mF cm−2 at a current density of 1 mA cm−2. Moreover, the carbon electrode obtained by annealing at a higher temperature of 550 °C showed the excellent rate capability and cyclic stability. For example, the 78% of initial capacitance retention was observed when the current density changed from 1 mA cm−2 to 8 mA cm−2, and the capacitance retention of 84% was achieved after 1000 charge/ discharge cycles. This 3D hierarchically structured carbon electrode can be considered as a potential candidate for next-generation energy storage devices.

The composites consisting of vanadium oxide nanoribbons and three-dimensional graphene (VOx-3DG) are synthesized using the hydrothermal method and they are employed as binder-free cathode for supercapacitors. Although VOx-3DG exhibits the high capacitance of 325 mF cm−2 at 1 mA cm−2 in 0.5 M KCl electrolyte, its cycling stability is very poor. Therefore, an innovative and effective method is proposed to improve the stability and capacitance of VOx-3DG by adding VOSO4 into KCl electrolyte. The function of the VOSO4 additive is twofold: (i) it facilitates electrodeposition of vanadium oxide nanoneedles over the electrode surface to keep the nanoribbon structure intact during charge-discharge process, and (ii) it serves as a redox-active electrolyte to provide the additional capacitance contribution via its specific V4+/V5+ conversion. Due to the aforementioned synergistic effects, VOx-3DG electrode after 500 cycles shows the capacitance of 8072 mF cm−2 at 2 mA cm−2, being 7.2 times higher than the initial value. A series of studies are performed to optimize the overall electrode performance. For example, the loading amount of electrodeposited vanadium oxide and electrode capacitance are profoundly modulated by several parameters such as the concentration of VOSO4, the concentration and pH value of the buffer solution. Finally, the asymmetric supercapacitor with VOSO4/KCl shows the increase in energy density by 33% compared with the one with pure KCl electrolyte. Furthermore, the former delivers a maximum energy density of 16 Wh kg−1 at a power density of 200 W kg−1 and exhibits 88% capacitance retention after 10,000 cycles.

In the present work, PdxGay alloys on oxygen-species-functionalized carbon nanotubes (PdxGay/OCNTs) are prepared as catalysts for the electrooxidation of formic acid by a facile method. Among all the catalysts, the catalyst with a Pd : Ga atomic ratio of 3.9 : 1 (Pd3.9Ga1) exhibits mass activity of 1321 A g−1 and improved stability. The functional groups on the modified CNT surfaces provide anchoring sites for Pd3.9Ga1 nanoalloys of 2 nm average size. Surface analysis reveals the appearance of a Pd 4d band center shift, which may weaken the adsorption of the formate intermediate. Pd3.9Ga1/OCNT with a modified electronic structure shows enhanced catalytic activity and stability towards the HCOOH oxidation reaction.

In this work, we have demonstrated the successful incorporation of selenium (Se)/tellurium (Te) into the covalently functionalized MoS2 (B-M) nanosheets as a host using a facile solvothermal method. The chalcogen-loaded composites (Se/Te@B-M-C) are characterized by various spectroscopic and microscopic analyses. These experiments prove that the amorphous Se/Te additive is homogeneously distributed over the MoS2 nanosheets with an expanded interlayer distance of ∼10 Å. The fabricated Li–S batteries composed of the Se/Te@B-M-C cathodes exhibit superior electrochemical performances when compared to that of the pristine chalcogens and bare host. The improved charge storage characteristics of these hybrids are attributed to the uniform distribution of chalcogens as the rate accelerators and the formation of a protective solid-electrolyte interphase layer over composites. The present study demonstrates that the structurally-engineered MoS2-based composites with evenly distributed amorphous Se (or Te) chalcogens as accelerators are potential candidates for next-generation high-performance lithium–sulfur batteries with high capacity and excellent cycle stability.

Engineering the polymers with electrochemical functionality is a topic of contemporary research towards developing lightweight and low-cost energy storage devices. In this study, a pair of organic polymers is successfully synthesized by coupling the redox-active moieties such as perylenetetracarboxylic diimide together through monosulfide and disulfide groups. The introduction of two different sulfide linkages in the polymeric chain yields two distinct morphologies due to the different structures of sulfide linkage groups. These polymers are tested as the electrode materials for supercapacitors in two different water-in-salt electrolytes. The interactions of K+/NH4+ ions with polymer electrodes are separately studied in 27 m potassium acetate (KAc) and 27 m ammonium acetate electrolytes. The polymer with monosulfide moieties shows better specific capacitance, rate capability, and cyclic stability in 27 m KAc compared to the one with disulfide moieties. In order to demonstrate the practical application, the asymmetric supercapacitors are fabricated by using the polymer and activated carbon as the negative and positive electrodes, respectively. The device with 27 m KAc delivers an energy density of 29.9 Wh kg-1 at the power density of 850 W kg-1 and exhibits 79% of the initial capacitance after 10000 charge-discharge cycles at the current density of 2 A g-1.

NiSe nanoparticles are electrodeposited over a forest of carbon nanotubes (CNTs) to form an intertwined and porous network. The assynthesized composite (denoted as CNT@NiSe/SS) is used as a free-standing and multifunctional electrode for both supercapacitors and overall water splitting applications. For a supercapacitor application, CNT@NiSe/SS exhibits higher specific capacity and improved rate capability compared with individual NiSe and CNTs. A hybrid supercapacitor device consisting of battery-like CNT@NiSe/SS and EDLC-like graphene delivers a maximum energy density of 32.1 Wh kg−1 at a power density of 823 W kg−1 and has excellent stability after a floating test of 50 h. On the other hand, CNT@NiSe/SS also serves as a bifunctional electrocatalyst with high activity for overall water splitting. The CNT@NiSe/SS electrode displays excellent hydrogen and oxygen evolution reaction performance with the lowest overpotential of 174 mV at 10 mA cm−2 and 267 mV at 50 mA cm−2, respectively. The symmetrical two-electrode system requires an operating potential of 1.71 V to achieve a current density of 10 mA cm−2. Furthermore, this electrolyzer shows a negligible increment in potential after 24 h of continuous water splitting. The outstanding performances of CNT@NiSe/SS can be attributed to the synergistic effect of NiSe and CNTs.

The development of electrocatalytic nitrogen reduction reaction (NRR) at ambient conditions as an alternative to traditional high-temperature ammonia synthesis is a vibrant research topic due to the potential to significantly reduce the energy consumption required for the production of ammonia. Several noble metal-based materials have already been identified as highly active electrocatalysts for this purpose. However, the development of non-precious metal-based electrocatalysts is necessary for realizing cost-effective ammonia synthesis at large scales. This work has explored the potential of the less exploited transition metal phosphorus trichalcogenide NiPS3 as an NRR electrocatalyst. Excellent NRR activities have been achieved by exfoliating bulk NiPS3 into bi- or tri-layered nanosheets. The NH3 yield attained using exfoliated NiPS3 is 118 μg h−1 mgcat-1 with a Faraday efficiency of > 17 % at an applied potential of −0.4 V vs RHE. The NRR performance of exfoliated NiPS3 in terms of NH3 yield surpasses many non-noble metal-based catalysts reported in the literature. Further, it also exhibited a stable NRR activity of > 90% even after several repetitive cycles. Plane-wave DFT calculations at the GGA + U level have been used to investigate the reaction pathways. It could be shown that the NNR follows an associative mechanism, with the very first hydrogenation step being the potential determining step.

Formation of an inferior solid-electrolyte interface (SEI) over the electrode severely diminishes the specific capacity and cyclic stability of Li-ion batteries (LIB). Although this issue is tackled to some extent by the in-situ generation of SEI coatings via the use of electrolyte additives, the control over the optimum thickness and composition of SEI is still challenging. To address this issue, porous and flexible SEI coating is electrochemically deposited over the active electrode material from an aqueous deep-eutectic solvent. The uniform SEI film of 20 to 35 nm with the composition of C, N, F, O, and Li elements is preformed on the surface of a self-assembled composite of 1T-MoS2 and the positively charged reduced graphene oxide. With the aid of preformed SEI, the composite electrode significantly increases its specific capacity from 907 to 1350 mAh g−1 and rate capability from 28 to 75%. Even at a higher current density of 1 A g−1, specific capacity gradually rises from 960 to 1647 mAh g−1 after 2000 charge/ discharge cycles. Furthermore, the device shows indistinct electrolyte decomposition and negligible increase of charge transfer resistance during cycling. Our novel approach is extrapolated as a general protocol to improve the performance of LIBs.

In this work, a uniform thickness of a two-dimensional carbon layer wrapping a three-dimensional flower-like TiO2 (CFT) is used to support Pd nanoparticles (Pd/CFT) as efficient catalyst for selective oxidation of benzyl alcohol in a three-phase reaction system. The results of characterization reveal that the Ti O C bond plays a key role in establishing interactions between the CFT and Pd. In comparison to the Pd/AC catalyst, Pd nanoparticles (PdNPs) with active phases can be effectively anchored on the surfaces of CFT without obvious dynamic change under reaction conditions.

MoS2 has been viewed as a unique anode material for lithium-ion batteries; however, its electrochemical performance is usually restrained by poor conductivity of 2H phase and an uneven solid-electrolyte interphase (SEI). To tackle the above issues, the ternary composite is synthesized by self-assembling MoS2 2D sheets with higher percentage of metallic 1T-phase on polyaniline functionalized reduced graphene oxide (PANI-rGO) through an electrostatic interaction. The flower-like aggregate of 1T-MoS2 having increased interlayer distances is beneficial for diffusion and intercalation of lithium ions. Furthermore, the graphene substrate facilitates the electron transportation. At the current density of 0.1 and 2 A g−1, the ternary composite has the specific capacities of 812 and 333 mAh g−1 respectively. On the other hand, the cyclic stability of ternary composite can be further improved when 10 wt% fluoroethylene carbonate (FEC) is added into the traditional carbonate-based electrolyte. The capacity retention of ternary composite cycled in a FEC-mixed electrolyte is two times higher than that in a traditional electrolyte after 400 charge–discharge cycles. This is attributed to the fact that the use of FEC enables the formation of active LiF-rich SEI.

Aqueous all-organic battery-supercapacitor hybrid (BSH) devices are emerging as promising alternative energy storage systems to conventional metal-ion batteries/supercapacitors in terms of their easy processability, high tunability, cost-effectiveness, and recyclability. In this study, we demonstrate an all-organic BSH device using a record concentration of ammonium acetate (30 m NH4Ac) as a cheap and green electrolyte. This novel water-in-salt system possesses an electrochemical stability window up to 2.1 V. In addition, organic polymers comprising of perylenetetracarboxy diimide core and the mixed aromatic amine groups are employed as negative and positive electrodes, respectively. The polymers show low water solubility, good crystallinity, and nano-morphology, which make them decent candidates for the all-organic aqueous BSH device. More importantly, electrochemical kinetic analysis of polymer electrodes reveals that the negative and positive electrodes display pseudocapacitive and battery-type behaviors, respectively. For the first time, an all-organic BSH device with 30 m NH4Ac is fabricated, which delivers a specific capacity of 42 mA h g−1 at 200 mA g−1 and capacity retention of ca. 63% after 5000 cycles. It further shows the maximum energy density of 16.5 Wh kg−1 and power density of 719 Wh kg−1, depicting great potential in energy storage applications.

Herein, we report a facile method to prepare palladium nanoparticles (Pd NPs) anchored on nitrogen-doped carbon nanotubes (Pd/NCNTs) with particle size distribution uniformed. The Pd/NCNTs exhibits excellent ethanol oxidation reaction (EOR) mass activity of 2,489 A g−1, which is 5.1 times higher than commercial Pd/C. However, the anodic reaction of EOR suffers from poor efficiency and low durability. In order to solve the problem of low durability and have better understanding of the degradation mechanism of anodic catalysts, identical-location transmission electron microscopy (IL-TEM), X-ray photoelectron spectroscopy (XPS), and electrochemical measurements were carried out. These were applied to Pd/NCNTs catalyst under EOR in alkaline media. The results showed that the leaching of Pd NPs and the reduction of surface metallic Pd0 were the main reasons for the decreased EOR activity. These findings provide practical guidance for the development of catalysts with higher activity and stability for energy conversion.

The Maxwell-Boltzmann speed distribution is the probability distribution that describes the speeds of the particles of ideal gases. The Maxwell-Boltzmann speed distribution is valid for both un-mixed particles (one type of particle) and mixed particles (two types of particles). For mixed particles, both types of particles follow the Maxwell-Boltzmann speed distribution. Also, the most probable speed is inversely proportional to the square root of the mass. This paper proves the Maxwell-Boltzmann speed distribution and the speed ratio of mixed particles using computer-generated data based on Newton’s law of motion. To achieve this, this paper derives the probability density function ψ^ab(u_a;v_a,v_b) of the speed u_a of the particle with mass M_a after the collision of two particles with mass M_a in speed v_a and mass M_b in speed v_b. The function ψ^ab(u_a;v_a,v_b) is obtained through a unique procedure that considers (1) the randomness of the relative direction before a collision by an angle α. (2) the randomness of the direction after the collision by another independent angle β. The function ψ^ab(u_a;v_a,v_b) is used in the equation below for the numerical iterations to get new distributions P_new^a(u_a) from old distributions P_old^a(v_a), and repeat with P_old^a(v_a)=P_new^a(v_a), where n_a is the fraction of particles with mass M_a. P_new^1(u_1)=n_1 ∫_0^∞ ∫_0^∞ ψ^11(u_1;v_1,v’_1) P_old^1(v_1) P_old^1(v’_1) dv_1 dv’_1 +n_2 ∫_0^∞ ∫_0^∞ ψ^12(u_1;v_1,v_2) P_old^1(v_1) P_old^2(v_2) dv_1 dv_2 P_new^2(u_2)=n_1 ∫_0^∞ ∫_0^∞ ψ^21(u_2;v_2,v_1) P_old^2(v_2) P_old^1(v_1) dv_2 dv_1 +n_2 ∫_0^∞ ∫_0^∞ ψ^22(u_2;v_2,v’_2) P_old^2(v_2) P_old^2(v’_2) dv_2 dv’_2 The final distributions converge to the Maxwell-Boltzmann speed distributions. Moreover, the square of the root-mean-square speed from the final distribution is inversely proportional to the particle masses as predicted by Avogadro’s law.

Hierarchical Co9S8 hollow microspheres with nanosheet building units are synthesized via a one-step hydrothermal method. The presence of glucose in the synthesis is essential to the formation of hollow structure and influences the size and morphology of microsphere. Benefiting from the advantages of a hollow architecture, conductive carbon coating and Co9S8 nanosheet units, the composite exhibits the outstanding electrochemical properties. When the composite electrode is evaluated as the cathode material for supercapacitors, it exhibits the high specific capacitance of 514 F g-1 at 1.0 A g-1 and a capacitance retention of ca. 88% over 1000 cycles at 8 A g-1. On the other hand, the nanosheet-constructed hollow structure can efficiently promote the electrocatalytic activity of Co9S8 toward oxygen evolution reaction. Due to the fact that Co9S8 nanosheets impart largely exposed active sites, the composite exhibits a low Tafel slope of 66 mV dec-1 and no obvious degradation after 12 h water oxidation.

The composite of MoS2 and hollow carbon sphere (MoS2@HCS) is prepared via a glucose-assisted one pot synthesis. The composite consists of hierarchical spheres with a diameter of 0.5–4 μm and these hollow spheres are decorated with a number of curled and interlaced MoS2 nanosheets. After the composite is subject to the lithium intercalation, the MoS2 is converted from 2H to 1T phase. In this current work, the activities of 1T-MoS2@HCS toward photocatalytic hydrogen evolution and the reduction of I3− in dye-sensitized solar cells (DSCs) are systemically investigated. When evaluated as the photocatalyst for hydrogen evolution, the amount of evolved hydrogen over 1T-MoS2@HCS can reach 143 μmol in 2 h, being 3.6 times higher than as-synthesized 2H-MoS2@HCS. Additionally, the 1T-MoS2@HCS can be employed as the counter electrode (CE) material in DSCs. The DSCs based on 1T-MoS2@HCS CE possesses the power conversion efficiency of 8.94%, being higher than that with 2H-MoS2@HCS CE (8.16%) and comparable to that with Pt CE (8.87%). Our study demonstrates that 1T-MoS2@HCS has a great potential as an inexpensive alternative to Pt catalysts.

A hierarchically structured nanocomposite consisting of ultrathin MoS2 nanosheets densely dispersed on the surface of hollow carbon spheres (MoS2@HCS) is prepared through a glucose-assisted, one-pot synthesis. When evaluated as the cathode material for supercapacitors, MoS2@HCS exhibits pseudocapacitive behavior in a KOH electrolyte. More importantly, the capacitive performance of MoS2@HCS can be further boosted by activating the composite electrode in a KOH solution. The activation process partially removes the carbonaceous materials covering the MoS2 surface, which leads to more exposure of active electrode materials to the electrolyte. Activated MoS2@HCS exhibits a high specific capacitance value of 458 F g−1 at 1 A g−1, which is approximately 2.5 times higher than that of the MoS2 electrode. Furthermore, MoS2@HCS exhibits remarkable cycling stability, with a capacitance retention of about 86% over 1000 cycles at 8 A g−1. To further demonstrate the practical applications of composite electrode, an asymmetric supercapacitor device (ASC) is fabricated by using activated MoS2@HCS and reduced graphene oxide as the positive and the negative electrodes, respectively. The fabricated device delivers a maximum energy density of 13.7 Wh kg−1 at a power density of 616 W kg−1. Even at a high power density of 4.9 kW kg−1, the ASC device can still retain 80% of the maximum energy density.

In the present study, Pd nanoparticles supported on phosphorus-incorporated porous carbon frameworks were prepared and used in selective phenylacetylene hydrogenation. The results showed that the interaction between Pd and the doped support affected the electron density and chemisorption properties of the Pd nanoparticles, and thus enhanced the catalytic performance for phenylacetylene hydrogenation.

Phosphorous oxide (PxOy)-incorporated carbon nanotubes (PCNTs) and nitric acid treated carbon nanotubes (OCNTs) are first synthesized, then phosphorous modified palladium nanoparticles (Pd-P NPs) supported on PCNTs (Pd-P/PCNTs) and OCNTs (Pd-P/OCNTs) are synthesized and employed as electrocatalysts in a methanol oxidation reaction. Pd-P/PCNTs show enhanced electrocatalytic activity and stability in comparison to Pd-P/OCNTs. Combining surface analysis and electrochemical performance, PxOy incorporated into CNTs could create anchoring sites for Pd ions and P precursors, which could facilitate the synthesis of Pd-P NPs in an aqueous solution containing Pd ions and sodium hypophosphite serving as a reducing agent and a P source. The electronic modification of embedded Pd-P NPs on PxOy-incorporated CNTs accounts for the enhanced electrochemical performance of Pd-P/PCNTs.

In this work, a 3D porous carbon framework (PCF) supporting palladium nanoparticles (Pd/PCF) was synthesized by a simple and economical method and used for catalyzing benzyl alcohol oxidation in a continuous-flow reactor. Structural and surface characterization revealed that this coral-like PCF with increased hydrophobic and basic surface properties promotes the adsorption and desorption of the reactant and products, and also suppresses the disproportionation and facilitates the oxidation of benzyl alcohol at the same time. The Pd/PCF catalyst exhibited an improved performance in activity, selectivity, and stability when compared to the same Pd supported on a typical activated carbon (AC).

The Maxwell-Boltzmann speed distribution is the probability distribution that describes the speeds of the particles of ideal gases. The Maxwell-Boltzmann speed distribution is valid for both un-mixed particles (one type of particle) and mixed particles (two types of particles). For mixed particles, both types of particles follow the Maxwell-Boltzmann speed distribution. Also, the most probable speed is inversely proportional to the square root of the mass. The Maxwell-Boltzmann speed distribution of mixed particles is based on kinetic theory; however, it has never been derived from a mechanical point of view. This paper proves the Maxwell-Boltzmann speed distribution and the speed ratio of mixed particles based on probability analysis and Newton’s law of motion. This paper requires the probabilitydensity function (PDF) ψ^ab(u_a; v_a, v_b)of the speed u_a of the particle with mass M_a after the collision of two particles with mass M_a in speed v_a and mass M_b in speed v_b . The PDF ψ^ab(u_a; v_a, v_b) in integral form has been obtained before. This paper further performs the exact integration from the integral form to obtain the PDF ψ^ab(u_a; v_a, v_b) in an evaluated form, which is used in the following equation to get new distribution P_new^a(u_a) from old distributions P_old^a(v_a) and P_old^b(v_b). When P_old^a(v_a) and P_old^b(v_b) are the Maxwell-Boltzmann speed distributions, the integration P_new^a(u_a) obtained analytically is exactly the Maxwell-Boltzmann speed distribution. P_new^a(u_a)=∫_0^∞ ∫_0^∞ ψ^ab(u_a;v_a,v_b) P_old^a(v_a) P_old^b(v_b) dv_a dv_b, a,b = 1 or 2 The mechanical proof of the Maxwell-Boltzmann speed distribution presented in this paper reveals the unsolved mechanical mystery of the Maxwell-Boltzmann speed distribution since it was proposed by Maxwell in 1860. Also, since the validation is carried out in an analytical approach, it proves that there is no theoretical limitation of mass ratio to the Maxwell-Boltzmann speed distribution. This provides a foundation and methodology for analyzing the interaction between particles with an extreme mass ratio, such as gases and neutrinos.

Herein, we are the first to develop a co-solvent-in-deep eutectic solvent (DES) system by mixing water and acetonitrile with a typical DES electrolyte consisting of acetamide and lithium perchlorate. The addition of co-solvents not only solves the problems of high viscosity and low conductivity of DES but also provides some unique properties. For example, the presence of water improves the flame-retardant property of the DES electrolyte. In contrast, the addition of acetonitrile further improves the ionic conductivity without compromising a wide electrochemical stability window (ESW). The effects of the amount of co-solvent in DES and the optimal molar ratio between co-solvents have been investigated. When the molar ratio of acetonitrile to water is 4.4:1, hybrid DES shows the best physical properties, including a wide ESW (2.55 V), superior conductivity (15.6 mS cm−1), and low viscosity (5.82 mPa·s). Furthermore, a series of spectroscopic measurements have been performed to understand the interaction among electrolyte components. It was found that water molecules were strongly coordinated to Li+ ions, and such interaction was not affected by the presence of acetonitrile molecules. On the other hand, we have demonstrated using hydrogel consisting of 1T-MoS2 and reduced graphene oxide (rGO) as the electrode materials for supercapacitors. This hydrogel inherited the porous structure of rGO hydrogel and the high conductivity of 1T-MoS2. Finally, high voltage symmetric supercapacitors have been fabricated by using hybrid DES and hydrogel as the electrolyte and electrode, respectively. An optimized supercapacitor works at a wide operating voltage of 2.3 V and achieves the maximum energy density of 31.2 Wh kg−1 at a power density of 1164 W kg−1. Furthermore, this device exhibited 91% capacitance retention after 20,000 cycles.

The selective enrichment of a highly active form/phase of material is essential for the development of potential candidates for specific applications. Herein, we demonstrate the first example of the covalent functionalization of a highly active 1T phase of outstanding 2D material, such as MoS2, and its enrichment (>94%) using a solvent extraction technique. Covalent functionalization stabilizes the metastable 1T phase with increased interlayer distance, which makes it a more suitable candidate for energy applications. The enriched functionalized 1T-MoS2 with n-butyl groups (en-Bu-1T-MoS2) shows a lower overpotential of 169 mV (vs. Reversible Hydrogen Electrode, RHE) with the loading mass of 0.9 mg cm−2 toward the hydrogen evolution reaction (HER). The continuous HER of en-Bu-1T-MoS2-based electrode for >200 h showed only

Photocatalytic production of H2 by water splitting gives a promising solution to growing demands for clean and sustainable energy. In this work, we demonstrate the first example of using localized surface plasmon resonance (LSPR) of gold nanoparticles (AuNPs) to enhance the activity of a dye-sensitized photocatalytic system toward hydrogen evolution. For the synthesis of the photocatalyst, the AuNPs and Ni3S2 were co-deposited onto the conductive backbones of multi-walled carbon nanotubes (AuNPs@NiS@CNT) using a glucose-assisted hydrothermal method. The activity of AuNPs@NiS@CNT has been studied by sensitizing the photocatalyst with Erythrosin Yellowish (ErY) in a solution of the sacrificial reagent. It is found that AuNPs@NiS@CNT shows superior photocatalytic activity to the AuNP-free photocatalyst due to the fact that plasmonic AuNPs can significantly enhance the light-harvesting characteristics of ErY sensitizers. Furthermore, the photocatalytic activity of AuNPs@NiS@CNT nonlinearly increases with AuNP loading content and the optimal AuNP loading in the photocatalyst is 1 wt%. Compared with the AuNP-free photocatalyst, the addition of 1 wt% AuNPs to the photocatalyst leads to a 127% increase in the amount of hydrogen evolved. In addition to the contribution from the LSPR of AuNPs, the photocatalytic enhancement of AuNPs@NiS@CNT can be ascribed to the fact that the excellent electron transport properties of CNTs allow the electrons from photoexcited ErY molecules to efficiently transfer to the Ni3S2 catalyst and simultaneously prevent charge recombination. More importantly, by activating AuNPs(1 wt%)@NiS@CNT in a 1 M KOH solution for 3 days, the amount of evolved hydrogen in 3 h can be further increased to 1110 μmol. This KOH treatment may remove the partial amorphous carbon on the Ni3S2 surface to increase the number of active sites for photocatalytic hydrogen evolution. Because AuNPs@NiS@CNT shows reasonable stability and a high apparent quantum yield of 8.1%, it has great potential to be a low-cost photocatalyst for hydrogen evolution.

In this study, we demonstrate the formation of azo compounds on a composite of silver nanoparticles and graphene oxides (Ag@G) through a plasmon-assisted coupling reaction between different amine compounds. According to the time-dependent SERS experiments, 4-aminothiophenol (4ATP) molecules on Ag@G can be associated with external reactants such as 4-nitroaniline to form azo compounds when aided by the plasmons. Furthermore, the rate of the coupling reaction is dependent on the wavelength and the power of the excitation laser. It is noteworthy that the coupling reaction can only occur between two compounds containing amino groups in the presence of Ag nanoparticles. On the other hand, the NN double bond in the azo compound can be dissociated in a NaBH4 solution after 532 nm laser irradiation. The reduction of the azo compound results in the recovery of 4ATP molecules on Ag@G. Finally, we demonstrate that the plasmon-assisted coupling reaction allows for the immobilization of amine-terminated DNAs on 4ATP modified Ag@G. This DNA modified Ag@G can serve as the SERS substrate to sensitively detect its complementary DNA.

In this current work, Al-doped carbon-coated Li4Ti5O12 (LTAO/C) composites were firstly synthesized via a facile sol–gel method, and subsequently employed as anode materials for high-rate lithium-ion batteries. According to extensive material characterization including X-ray diffraction spectroscopy, high-resolution transmission microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy, LTAO/C composites were successfully not only included with an Al dopant, but also coated with a uniform carbon layer. On the basis of the synergistic effect of the Al-doping and carbon-coating, the resultant LTAO/C electrode displayed superior rate capability and cycling stability. The LTAO/C electrode demonstrates impressive capacity retention of 85.3% at 20C with respect to the discharge capacity at 1C. Additionally, the LTAO/C electrode still retained 97.9% of its initial capacity even after 100 charge/discharge cycles. These results signify that the LTAO/C electrode can be potentially considered as one of the promising anode materials for high-rate lithium-ion batteries.

Herein, the ternary composite consisting of MoS3, Au core-Ag shell nanoparticles (Au@AgNP), and reduced graphene oxide (rGO) is synthesized for photocatalytic hydrogen evolution reaction. The various characterization studies reveal the co-existence of amorphous MoS3 nanoflakes and the Au@AgNP with the dual absorptions of surface plasmon resonance (SPR) in rGO nanosheets. With the help of single dye sensitization, the ternary composite exhibits a better photocatalytic activity of 9.6 mmol h−1 g−1 with the apparent quantum yield (AQY) of 7.8% and excellent long-term stability under visible light illumination. It also shows the wavelength-dependent photocatalytic activity under the different monochromatic light radiation. Interestingly, the photocatalytic performance of ternary composite further enhances when dual dyes are utilized for sensitization. The optimized photocatalytic reaction system shows a maximum H2 production rate of 10.6 mmol h−1 g−1 with the AQY of 8.6%. The higher activity of ternary photocatalysts is attributed to the amorphous MoS3 nanoflakes with the exposed reactive sites over the conductive rGO nanosheets, which promotes the electron transfer from photoexcited dyes to MoS3. More importantly, the extended SPR absorption of Au@AgNP in-line with the maximum absorption of dye molecules improves light-harvesting ability and efficiently stimulates the dye excitation.

We report a facile route to obtain MoS2/CdS heterostructure and tested for hydrogen production activity under visible light irradiation. The MoS2/CdS heterostructure containing 15 wt% MoS2 exhibits the highest H2 production rate of 27.720 mmol g−1 h−1, which is 30.7 times higher than CdS alone. This promotion of photocatalytic activity can be assigned to the modification of MoS2 on CdS surfaces by forming interfacial interactions, which effectively inhibits the recombination of photo-generated electrons and holes. Meanwhile, MoS2 exhibits a partially crystallized status, providing abundant exposed edges with coordinatively unsaturated S and Mo atoms as the photocatalytic active sites, thus facilitating hydrogen production.

A new kind of phosphorus-doped porous carbon framework (P-PCF) was synthesized using a simple and low-cost method and was used as a support material for loading Pd nanoparticles with an average diameter of 5~7 nm (Pd/P-PCF) for benzyl alcohol oxidation. Enhanced activity, selectivity, and stability were achieved over Pd/P-PCF in comparison to the undoped counterpart catalyst (Pd/PCF). Surface analysis of the fresh and reacted catalysts revealed that the selective oxidation of benzyl alcohol is favored using the Pd/P-PCF catalyst because of the modified electronic properties of Pd nanoparticles, the metal-support interactions, as well as the hydrophobic and basic surface properties of the catalyst, which originates from the phosphorus doping.

The Co 9 S 8 nanoparticles are homogeneously deposited on the conductive backbone of 3D graphene (3DG) by using a glucose-assisted hydrothermal method. The activation process for the composite of Co 9 S 8 and 3DG involving the consecutive cyclic voltammetry scanning in a 1 M KOH solution increases surface roughness of the composite electrode. As a result, the increase in the active surface area of the activated composite electrode leads to significant enhancement of electrode performance. Because the combination of the Co 9 S 8 nanoparticles and conductive 3DG generates a profound effect on the electrode, the activated composite electrode shows a high specific capacitance of 1721 F g −1 and great cycling stability at a relatively high current density of 16 A g −1 . Furthermore an asymmetric supercapacitor device assembled from the composite of Co 9 S 8 and 3DG and reduced graphene oxide hydrogel is tested to evaluate the capacitive performance of the composite electrode in a full-cell configuration. The fabricated device is capable of functioning with an output voltage of 1.8 V and delivering a maximum energy density of 31.6 Wh kg −1 at a power density of 910 W kg −1 . More importantly, the device exhibits great long-term stability with 86% capacitance retention after 6000 charge/discharge cycles.

Synchrotron radiation soft X-ray was employed to reduce graphene oxide (GO) films in ultrahigh vacuum. The dissociation of oxygen-containing functional groups, and the formation of sp2 C–C bonds were revealed by time-resolved in situ X-ray photoelectron spectroscopy, demonstrating the X-ray reduction of GO. The number of C–O bonds of GO exhibited an exponential decay with exposure time. The X-ray reduction rate of GO was positively correlated with the intensity of low-energy secondary electrons excited from substrates by soft X-ray, indicating the C–O bonds were dissociated by secondary electrons.