Rational design of hierarchical nanostructure arrays as integrated electrodes with the capability of storing energy has been studied extensively. However, a low electronic/ionic transport rate and structural instability hampered their practical application. In this study, we have fabricated carbon-sheathed NiMoO4 nanowires standing on nickel foam (NF) and employed as a free-standing electrode for supercapacitor. The unique structure revealed remarkable electrochemical behavior including a high areal capacitance, ∼70% capacitance retention at 100 mA cm–2, and an stability during cycling (86% retention after 50,000 cycles). In addition, an NF@NiMoO4@C//activated carbon hybrid supercapacitor presents 201.3 F g–1 of specific capacitance along with an 72.4 W h kg–1 of energy density. The carbon sheath, which prevents the structural pulverization of NiMoO4 and provides another conductive path together with Ni foam, is responsible for the superior electrochemical performances. Our work demonstrates an improved step toward rational design of high-performance integrated electrodes for a supercapacitor with a new vision for theoretical and practical applications.Keywords: Carbon; Integrated electrode; Ni foam; NiMoO4; Supercapacitor;

ZnS@MoS2 core–shell nanospheres were first prepared via a nanotemplate-assisted hydrothermal method. After the removal of ZnS with dilute hydrochloric acid, hollow MoS2 nanospheres (HNS) were successfully obtained. The as-synthesized HNS display a unique hollow structure assembled by ultrathin nanosheets with rich defects. Furthermore, the HNS exhibit an enhanced performance in the electrochemical energy storage devices, for example, in a Li-ion battery, they exhibit a discharge capacity of 750 mA h g−1 at a current density of 100 mA g−1 even after 50 cycles, and in a supercapacitor, they exhibit a specific capacitance of 142.0 F g−1 at a current density of 1 A g−1. These values are much higher than those obtained for their solid counterparts. The present study provides an easily available method for the design and fabrication of other hollow nanomaterials with high energy storage performances.

Clean Pt nanoclusters with a diameter of 1.0–2.4 nm, supported on reduced graphene oxide (rGO) nanosheets, were successfully synthesized by simple in situ thermolysis of a Pt-carbonyl complex. The supported Pt nanoclusters are in an electron-deficient state because of the electron transfer between the nanoclusters and the rGO sheets. The as-prepared Pt-1 nm/rGO shows high catalytic activity for the 100% selective hydrogenation of nitrobenzene, with the turnover frequency (TOF) reaching 975.4 h−1 at 25°C and 1 atm. This number is higher than the previously reported value for the heterogeneously catalyzed hydrogenation of nitrobenzene. The proposed process follows a direct hydrogenation mechanism, as is revealed by the analyses of the intermediate products. This work presents a facile and effective synthetic approach for achieving highly efficient nanocatalysts, and can be extended to obtain other metal catalysts with ultra-small sizes and excellent performance.本文以羰基铂为前驱体, 采用简便的原位热解方法, 成功地合成了负载在还原氧化石墨烯(rGO)纳米片上的直径为1.0–2.4 nm的清洁Pt纳米团簇. 由于Pt纳米团簇和rGO片之间的电子转移, 所制备的负载Pt纳米团簇处于缺电子状态. 在25°C、1 atm下, 制备的Pt纳米团簇-1 nm/rGO催化剂的硝基苯选择性加氢的转换频率(TOF)达到975.4 h−1. 这个数值是目前硝基苯的非均相催化氢化所报道的活性最高值. 此外, 根据中间产物分析, Pt-1 nm/rGO催化硝基苯加氢的机理是直接氢化. 这项工作在构筑高效催化剂方面提供了一个简单有效的途径, 并且可以进一步扩展制备其他具有超小尺寸和卓越性能的金属催化剂.

The synthesis of layered transition metal dichalcogenide nanocrystals with excellent properties in energy conversion and storage has been well documented in the past several years. However, due to the metallic character of Te, the realization of the chemical synthesis of uniform well-defined MoTe2 nanostructures still remains a challenge, especially to achieve metastable 1T′-MoTe2. In this work, we have developed a colloidal chemical strategy for the synthesis of ultrathin 1T′-MoTe2 nanosheets. The as-achieved sample was characterized by a layered-expanded feature with an interlayer distance of 0.723 nm and rich defects. The shapes of 1T′-MoTe2 can be controlled by varying Mo precursors and the reaction atmosphere, where CO plays an essential role in determining the nanosheet feature. Interestingly, the optimized few-layer 1T′-MoTe2 nanosheets can be used as an efficient supercapacitor electrode with specific capacitances of 1393 F g−1 and 714 F g−1 at current densities of 1 A g−1 and 100 A g−1, respectively. An asymmetric 1T′-MoTe2//activated carbon supercapacitor exhibits a maximum specific capacitance of 158.9 F g−1 with an energy density up to 56.4 W h kg−1. To the best of our knowledge, it is the first time that ultrathin MoTe2 nanosheets have been used as ideal electrode materials for supercapacitors. The present work highlights a facile synthetic strategy to realize uniform transition metal telluride nanostructures for enhancing their electrochemical performances.

•One-step solvothermal method to synthesize CoSe2/carbon paper catalytic electrode.•CoSe2 nanosheets on carbon paper as highly efficient electrochemical water splitting catalyst.•The interlayer of CoSe2 was expanded to offer more electroactive site.Water splitting associated with the conversion and storage of renewable energy is considered to be the most significant strategy to create hydrogen. Herein, an efficient self-supported electrode was developed by in-situ growth of interlayer expanded lamellar cobalt diselenide (CoSe2) nanosheets (NS) on carbon paper (CP) substrate (CoSe2 NS@CP). The analyses of TEM, SEM and XRD confirmed that the CP is homogeneously coated by few stacking layers of interlayer expanded lamellar structured CoSe2. This rationally designed nanostructure can provide more active sites for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The bifunctional electrode exhibits high electrocatalytic performance with −128 mV vs. RHE onset potential for the HER in 0.5 mol dm−3 H2SO4 and +1521 mV vs. RHE for the OER in 1.0 mol dm−3 KOH. Besides, small electrolysis potentials of −201.1 mV vs. RHE and +1636 mV vs. RHE are needed to drive the HER and OER at current density of 100 mA cm−2. Finally, a small overall cell voltage (ca. +1.75 V) was used to drive the water splitting reaction in 1.0 mol dm−3 KOH. The CoSe2 NS@CP electrode showed both excellent catalytic activity with overall current density of 100 mA cm−2 at 2.13 V and tremendous durability with negligible decrease in potential at a constant current of 20 mA cm−2 for more than 30 hours. Thus this rationally designed electrode material can be readily applied for large-scale water splitting process.Download high-res image (300KB)Download full-size image

In this work, rationally designed 3D cobalt sulfide nanoflowers (3D CoS NF) were prepared by a facile one-step solvothermal method. The 3D CoS NFs were assembled from low dimensional building blocks with thin 2D nanoflakes with an average thickness of 19 nm (between 1 and 100 nm). SEM and TEM images revealed that the flower-like hierarchitecture consisted with an average diameter of 12 μm. XRD data indicated that the as-prepared sample had a pure hexagonal CoS crystal structure. Such 3D CoS NF was applied for fast-charge storage device which delivered a specific capacity of 669 C g−1 at a current density of 1 A g−1. By assembling the 3D CoS NF into an asymmetric supercapacitor (ASC), the device showed 129.0 C g−1 capacity and long cycle stability (85.7% retention after 3000 cycles).

The development of visible-light-responsive photocatalysts is a promising challenge in the management of environmental pollution. Silver–silver halide nano-photocatalysts have received intensive attention due to their excellent photocatalytic performance in recent years, where silver nanoparticles/nanoclusters demonstrate plasmonic enhanced light absorption efficiency and have been considered as an important component in various functional photocatalytic nanocomposite materials, serving for harvesting visible light. This review provides an overall survey on the state-of-the-art silver–silver halide-based photocatalysts, fundamental understanding of their plasmonically induced photo-reactions and their major environmental applications. We first discuss the basic concepts of localized surface plasmon resonance, and outline the general mechanism of silver–silver halide-based photocatalysis. We then discuss the latest progress in the design and fabrication of silver halide based photocatalysis using various strategies. Next, we highlight some selected examples to demonstrate the new applications of silver/silver halide nano-photocatalysts. Eventually, we provide an outlook of the present challenges and some perspectives of new directions in this interesting and emerging research area.

•Layer expanded MoS2 nanosheet.•Hydrothermal synthesis of MoS2/CF nanocomposite.•Efficient HER electrocatalyst.Molybdenum disulfide (MoS2) has become a promising electrochemical catalyst for reduction of protons to hydrogen in the so-called hydrogen evolution reaction (HER). In order to increase the HER activity, a huge effort has been made to design MoS2 catalysts with affording more active sites and higher conductivity. In this paper, an efficient HER electrochemical catalyst has been developed through an in-situ reduction of ammonium tetrathiomolybdate (ATTM) on carbon fibers (CFs) to afford layer-expanded MoS2/CFs composites (LE-MoS2/CFs). X-ray diffraction (XRD) indicates the interlayer of MoS2 nanosheets was expanded with d spacing 9.9 Å, and transmission electron microscopy (TEM) shows the lattice distance as 0.99 nm, which is agreed with XRD data. The HER test shows that the LE-MoS2/CFs with Mo/C molar ratio of 0.04 has the highest catalytic activity with the lowest overpotential (131 mV vs. RHE) and the highest current density (10 mA cm−2 at 200 mV vs. RHE), owing to a balance between the numbers of exposed active edge sites of MoS2 and fast transport paths for electrons provided by CFs.

The design of efficient artificial photosynthetic systems that harvest solar energy to drive the hydrogen evolution reaction via water reduction is of great importance from both the theoretical and practical viewpoints. Integrating appropriate co-catalyst promoters with strong light absorbing materials represents an ideal strategy to enhance the conversion efficiency of solar energy in hydrogen production. Herein, we report, for the first time, the synthesis of a class of unique hybrid structures consisting of ultrathin Co(Ni)-doped MoS2 nanosheets (co-catalyst promoter) intimately grown on semiconductor CdS nanorods (light absorber). The as-synthesized one-dimensional CdS@doped-MoS2 heterostructures exhibited very high photocatalytic activity (with a quantum yield of 17.3%) and stability towards H2 evolution from the photoreduction of water. Theoretical calculations revealed that Ni doping can increase the number of uncoordinated atoms at the edge sites of MoS2 nanosheets to promote electron transfer across the CdS/MoS2 interfaces as well as hydrogen reduction, leading to an efficient H2 evolution reaction.

Uncontrolled massive CO2 emission into the atmosphere is becoming a huge threat to our global climate and environment. Carbon capture and storage (CCS), starting with the crucial step of CO2 capture and separation, provides a promising approach to alleviate this issue. The major challenge for CO2 capture and separation is exploring efficient adsorbent materials with high storage capacity and selectivity. This review firstly summarized the significant advancement in a variety of state-of-the-art adsorbent materials. Then, particular attention was focused on the practical strategies to enhance CO2 capture and separation based on current adsorbent materials by topological structure design, chemical doping, chemical functionalization, open metal sites, and electric fields. These strategies paved constructive ways for the design and synthesis of novel adsorbent materials. Finally, we gave a perspective view on future directions in this rapidly growing field.

•The presence of Ce improves the distribution of Pt nanoparticles on Pt/Ce–Al2O3.•Ce addition can enhance the surface reducibility of Pt nanoparticles.•There is an improvement of catalytic behavior at low Ce contents.•The Pt/Ce–Al2O3 catalyst showed the high resistance to carbon deposition.The catalyst of Pt nanoparticles loaded on Al2O3 support has been prepared by a facile liquid phase synthesis–ultrasonic vibration method. With propane dehydrogenation as a probe reaction, the influence of promoter cerium (Ce) on the catalyst was investigated by means of transmission electron microscope (TEM), X-ray diffraction (XRD), N2 adsorption–desorption, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy of CO adsorption, H2-temperature programmed reduction (H2-TPR), and catalytic properties for propane dehydrogenation. The results revealed that the Pt nanograins with diameter of 1.6–4.8 nm were evenly dispersed on the Ce-containing Al2O3 support. The introduction of a small amount Ce into Pt/Al2O3 results in a bimetallic surface interaction, enhancing the surface reducibility and dispersity of Pt nanoparticles. The study of propane dehydrogenation performance shows that Ce-containing Pt catalyst is more active and less coke deposition than Ce-free Pt/Al2O3 counterpart. This study can provide an insight into the design and development of new Pt-based catalyst, especially for the improvement of catalytic activity and stability towards alkane dehydrogenation.

Owing to far-ranging industrial applications and theoretical researches, tailored synthesis of well-defined nanocrystals has attracted substantial research interest. Herein, β-AgI nanoplates have been synthesized through a facile polyvinylpyrrolidone (PVP)-assisted-aqueous-solution (PAAS) method under mild conditions. The parametric studies on the effect of ratio of reactants, solvents and surfactants were performed, revealing that a molar ratio of I− to Ag+ of 1.2 in deionized water and the presence of appropriate PVP as stabilizing agent can stimulate the preferred orientation growth of AgI nanoplates. The as-synthesized AgI nanoplates exhibit excellent photocatalytic activity and enhanced durability towards the degradation of organics, i.e., rhodamine B (RhB), under visible light illumination in comparison with corresponding bulk nanoparticles. A possible photocatalytic reaction mechanism was discussed, revealing O2˙− and h+ are main reactive species and free ˙OH radicals in solution also contribute to the degradation reaction. The superior photocatalytic performance renders the as-achieved AgI nanoplates promising candidates for applications in the fields of environmental purification or water disinfection. The present work opens an avenue to the synthesis of other shaped silver halide nanophotocatalysts.

Hollow CdS nanostructures have been synthesized by a two-step ionic exchange route, which consists of a first synthesis of Ag2S intermediated hollow frames derived from the reaction of S2− ions with AgCl cube-tetrapods, and a subsequent ion-exchange conversion of the obtained Ag2S to CdS hollow nanoframes. The investigation of the corresponding transformation process with scanning electronic microscopy (SEM) revealed that the obtained CdS particles preserved the framework of the original template. The solar-driven hollow structured CdS modified with 5% (w/w) of promoter of Pt nanoparticles/nanoclusters manifested a high hydrogen evolution rate of 10.07 mmol h−1 g−1, corresponding to the apparent quantum yield of 9.6% measured at a single length of 435 nm, which is due to efficient charge separation, fast transport of the photogenerated carriers, and fast photochemical reaction at the CdS/Pt/electrolyte interfaces. The present work can benefit the development of other hollow structured nano-photocatalysts with high efficiency towards new energy applications.

•Concave AgI nanoparticles have been synthesized for the first time.•Concave AgI nanoparticles exhibit a much higher efficiency in photocatalysis.•Concaving particles benefit adsorption capacity and interfacial electron transfer.•The surfaces in concave AgI nanoparticles are different from those in spherical AgI nanoparticles.Concave particles represent a new class of structures with their surfaces curving in or hollowed inward and thus presence of regions with negative curvatures. Owing to the potential high-index facets and negative curvatures, crystalline particles with concave surfaces are expected to show unexplored or substantially enhanced performance in comparison with the counterpart particles with convex surfaces. In this report, we highlight a facile approach for the first-time synthesis of concave AgI nanoparticles through a controlled etching of spherical AgI particles in a solution containing ethylenediamine, absolute alcohol, and polyvinylpyrrolidone. Physical parameters including morphology and size of the resulting concave AgI particles can be tuned by carefully controlling the reaction conditions such as the amount of precursors and the injection rate of precursor solutions. Most importantly, the concave AgI particles exhibit a much higher efficiency towards photocatalytic degradation of organic molecules than the corresponding spherical AgI particles. The as-synthesized concave AgI particles are expected to be useful not only for the fundamental investigation on shape- and composition-dependent properties but also for potential applications in photocatalysis, electrocatalysis, photonics, etc.Concave AgI nanoparticles have been synthesized through controlled etching of spherical AgI particles. The concave particles exhibit a much higher photocatalytic activity than the spherical ones towards degradation of organic pollutant.

Three-dimensional (3D) TiO2 with an acanthosphere-like morphology composed of nanothorns has been used as a suitable support to fabricate a visible-light-induced 3D AgI@TiO2 nanophotocatalyst. The structural characterization revealed that the size of the obtained AgI@TiO2 nanocomposite was close to that of pristine TiO2 particles, where AgI nanoparticles were evenly dispersed on the surfaces of “thorns” of TiO2. The as-achieved 3D AgI@TiO2 nanophotocatalyst exhibited enhanced photocatalytic performance towards photodegradation of organic pollutants, e.g., rhodamine B (RhB), in comparison with TiO2, P25, AgI and AgI@P25 with the same quantity. The enhanced photocatalytic performance is attributed to the strong visible light absorption and the defined interfaces between AgI nanoparticles and TiO2 nanothorns with efficient separation of photogenerated carriers. The excellent performance of the 3D AgI@TiO2 nanophotocatalyst suggests its promising applications in water treatment and environmental remediation.

Heterostructured Ag@AgBr/AgCl nanocashews have been synthesized by an anion-exchange reaction between AgCl nanocubes and Br− ions followed by photoreduction. Compared to polyhedral Ag@AgBr nanoparticles, the obtained nanostructures exhibit enhanced photocatalytic activity towards decomposition of organic pollutants, i.e., rhodamine-B (RhB). For example, only 2 min is taken to completely decompose RhB molecules with the assistance of these novel heterostructured nanoparticles under visible light irradiation. Furthermore, the as-synthesized nanocatalyst can be reused 20 times without losing activity, showing its high stability. Interestingly, the novel heterostructured Ag@AgBr/AgCl nanophotocatalyst also shows efficient visible light conversion of CO2 to energetic fuels, e.g. methanol/ethanol. Therefore, the present route opens an avenue to achieve highly efficient visible-light-driven nanophotocatalysts for applications in environmental remediation and resourceful use of CO2.

A magnetic visible-light response core-shell Fe3O4@SiO2@AgCl:Ag nanocomposites with enhanced photocatalytic performance has been prepared by combining polyol, sol–gel and photo-reduction methods. Room temperature magnetic hysteresis curves show that the as-synthesized Fe3O4@SiO2@AgCl:Ag nanoparticles display ferromagnetic behaviour with saturation magnetization of 10.76 emu g−1. This property indicates that the nanophotocatalyst can be easily separated by applying an external magnetic field. Furthermore, the as-achieved nanophotocatalyst exhibits high activity and stability toward decomposition of organic pollutant, e.g., Rhodamine B (RhB). For example, it takes only 4 min to degrade RhB molecules with the assistance of magnetic nanocomposites under visible-light irradiation. The nanophotocatalyst can be reused eight times without loss of activity. The high activity, stability and magnetic recyclability of the nanophotocatalyst afford it promising applications in environmental remediation, water disinfection and potential use in industry.

Uniform AgCl nanocubes with an average edge length of 85 nm have been prepared by a facile reverse micelle method. Partially reducing the as-produced AgCl nanocubes enables us to achieve a class of sunlight-driven plasmonic AgCl:Ag nanophotocatalysts. The optical absorption spectrum of the thus-achieved nanophotocatalyst exhibits strong absorption in the visible region due to surface plasmon resonance (SPR) of silver nanoparticles. Under sunlight illumination the hybrid AgCl:Ag nanoparticles exhibit high activity and durability towards decomposition of organic pollutant, e.g., methyl orange. The catalyst can be reused for 19 times without loss of activity. The possible photocatalytic mechanism is discussed, which indicates that metallic silver nanograins (or nanoparticles) play a critical role in enhancing photocatalytic performance and stabilizing the photocatalyst. These features mean the present nanophotocatalyst can be applied in environmental remediation, and waste water disinfection.

Oil-soluble MoS2 nanoparticles with narrow size distribution have been synthesized by a facile composite-surfactants-aided-solvothermal process. The as-prepared nanoparticles can be directly used as hydrogenation nanocatalysts or as precursors to achieve efficient supported nanocatalysts. The surfaces of these nanoparticles are proposed to be encapsulated within a layer of organic modifiers, which are responsible for the enhancement of their solubility in organic solvents. The activated-carbon supported MoS2 nanocatalysts exhibit higher activity than the unsupported ones towards hydrogenation reactions of naphthalene, owing to the synergistic effects between nanoparticles and supports. The advantages of the present nanocatalysts, such as removal of conventional presulfiding requirements and reduction of nanoparticle aggregations, make them become promising applications in related petroleum chemical industry.

Owing to far-ranging industrial applications and theoretical researches, tailored synthesis of well-defined nanocrystals has attracted substantial research interest. Herein, β-AgI nanoplates have been synthesized through a facile polyvinylpyrrolidone (PVP)-assisted-aqueous-solution (PAAS) method under mild conditions. The parametric studies on the effect of ratio of reactants, solvents and surfactants were performed, revealing that a molar ratio of I− to Ag+ of 1.2 in deionized water and the presence of appropriate PVP as stabilizing agent can stimulate the preferred orientation growth of AgI nanoplates. The as-synthesized AgI nanoplates exhibit excellent photocatalytic activity and enhanced durability towards the degradation of organics, i.e., rhodamine B (RhB), under visible light illumination in comparison with corresponding bulk nanoparticles. A possible photocatalytic reaction mechanism was discussed, revealing O2˙− and h+ are main reactive species and free ˙OH radicals in solution also contribute to the degradation reaction. The superior photocatalytic performance renders the as-achieved AgI nanoplates promising candidates for applications in the fields of environmental purification or water disinfection. The present work opens an avenue to the synthesis of other shaped silver halide nanophotocatalysts.

The development of visible-light-responsive photocatalysts is a promising challenge in the management of environmental pollution. Silver–silver halide nano-photocatalysts have received intensive attention due to their excellent photocatalytic performance in recent years, where silver nanoparticles/nanoclusters demonstrate plasmonic enhanced light absorption efficiency and have been considered as an important component in various functional photocatalytic nanocomposite materials, serving for harvesting visible light. This review provides an overall survey on the state-of-the-art silver–silver halide-based photocatalysts, fundamental understanding of their plasmonically induced photo-reactions and their major environmental applications. We first discuss the basic concepts of localized surface plasmon resonance, and outline the general mechanism of silver–silver halide-based photocatalysis. We then discuss the latest progress in the design and fabrication of silver halide based photocatalysis using various strategies. Next, we highlight some selected examples to demonstrate the new applications of silver/silver halide nano-photocatalysts. Eventually, we provide an outlook of the present challenges and some perspectives of new directions in this interesting and emerging research area.

Uncontrolled massive CO2 emission into the atmosphere is becoming a huge threat to our global climate and environment. Carbon capture and storage (CCS), starting with the crucial step of CO2 capture and separation, provides a promising approach to alleviate this issue. The major challenge for CO2 capture and separation is exploring efficient adsorbent materials with high storage capacity and selectivity. This review firstly summarized the significant advancement in a variety of state-of-the-art adsorbent materials. Then, particular attention was focused on the practical strategies to enhance CO2 capture and separation based on current adsorbent materials by topological structure design, chemical doping, chemical functionalization, open metal sites, and electric fields. These strategies paved constructive ways for the design and synthesis of novel adsorbent materials. Finally, we gave a perspective view on future directions in this rapidly growing field.

Uniform AgCl nanocubes with an average edge length of 85 nm have been prepared by a facile reverse micelle method. Partially reducing the as-produced AgCl nanocubes enables us to achieve a class of sunlight-driven plasmonic AgCl:Ag nanophotocatalysts. The optical absorption spectrum of the thus-achieved nanophotocatalyst exhibits strong absorption in the visible region due to surface plasmon resonance (SPR) of silver nanoparticles. Under sunlight illumination the hybrid AgCl:Ag nanoparticles exhibit high activity and durability towards decomposition of organic pollutant, e.g., methyl orange. The catalyst can be reused for 19 times without loss of activity. The possible photocatalytic mechanism is discussed, which indicates that metallic silver nanograins (or nanoparticles) play a critical role in enhancing photocatalytic performance and stabilizing the photocatalyst. These features mean the present nanophotocatalyst can be applied in environmental remediation, and waste water disinfection.

ZnS@MoS2 core–shell nanospheres were first prepared via a nanotemplate-assisted hydrothermal method. After the removal of ZnS with dilute hydrochloric acid, hollow MoS2 nanospheres (HNS) were successfully obtained. The as-synthesized HNS display a unique hollow structure assembled by ultrathin nanosheets with rich defects. Furthermore, the HNS exhibit an enhanced performance in the electrochemical energy storage devices, for example, in a Li-ion battery, they exhibit a discharge capacity of 750 mA h g−1 at a current density of 100 mA g−1 even after 50 cycles, and in a supercapacitor, they exhibit a specific capacitance of 142.0 F g−1 at a current density of 1 A g−1. These values are much higher than those obtained for their solid counterparts. The present study provides an easily available method for the design and fabrication of other hollow nanomaterials with high energy storage performances.

Three-dimensional (3D) TiO2 with an acanthosphere-like morphology composed of nanothorns has been used as a suitable support to fabricate a visible-light-induced 3D AgI@TiO2 nanophotocatalyst. The structural characterization revealed that the size of the obtained AgI@TiO2 nanocomposite was close to that of pristine TiO2 particles, where AgI nanoparticles were evenly dispersed on the surfaces of “thorns” of TiO2. The as-achieved 3D AgI@TiO2 nanophotocatalyst exhibited enhanced photocatalytic performance towards photodegradation of organic pollutants, e.g., rhodamine B (RhB), in comparison with TiO2, P25, AgI and AgI@P25 with the same quantity. The enhanced photocatalytic performance is attributed to the strong visible light absorption and the defined interfaces between AgI nanoparticles and TiO2 nanothorns with efficient separation of photogenerated carriers. The excellent performance of the 3D AgI@TiO2 nanophotocatalyst suggests its promising applications in water treatment and environmental remediation.

A magnetic visible-light response core-shell Fe3O4@SiO2@AgCl:Ag nanocomposites with enhanced photocatalytic performance has been prepared by combining polyol, sol–gel and photo-reduction methods. Room temperature magnetic hysteresis curves show that the as-synthesized Fe3O4@SiO2@AgCl:Ag nanoparticles display ferromagnetic behaviour with saturation magnetization of 10.76 emu g−1. This property indicates that the nanophotocatalyst can be easily separated by applying an external magnetic field. Furthermore, the as-achieved nanophotocatalyst exhibits high activity and stability toward decomposition of organic pollutant, e.g., Rhodamine B (RhB). For example, it takes only 4 min to degrade RhB molecules with the assistance of magnetic nanocomposites under visible-light irradiation. The nanophotocatalyst can be reused eight times without loss of activity. The high activity, stability and magnetic recyclability of the nanophotocatalyst afford it promising applications in environmental remediation, water disinfection and potential use in industry.

The synthesis of layered transition metal dichalcogenide nanocrystals with excellent properties in energy conversion and storage has been well documented in the past several years. However, due to the metallic character of Te, the realization of the chemical synthesis of uniform well-defined MoTe2 nanostructures still remains a challenge, especially to achieve metastable 1T′-MoTe2. In this work, we have developed a colloidal chemical strategy for the synthesis of ultrathin 1T′-MoTe2 nanosheets. The as-achieved sample was characterized by a layered-expanded feature with an interlayer distance of 0.723 nm and rich defects. The shapes of 1T′-MoTe2 can be controlled by varying Mo precursors and the reaction atmosphere, where CO plays an essential role in determining the nanosheet feature. Interestingly, the optimized few-layer 1T′-MoTe2 nanosheets can be used as an efficient supercapacitor electrode with specific capacitances of 1393 F g−1 and 714 F g−1 at current densities of 1 A g−1 and 100 A g−1, respectively. An asymmetric 1T′-MoTe2//activated carbon supercapacitor exhibits a maximum specific capacitance of 158.9 F g−1 with an energy density up to 56.4 W h kg−1. To the best of our knowledge, it is the first time that ultrathin MoTe2 nanosheets have been used as ideal electrode materials for supercapacitors. The present work highlights a facile synthetic strategy to realize uniform transition metal telluride nanostructures for enhancing their electrochemical performances.