g Qin

Solvothermal synthesis of hierarchical flower-like β-NiS with excellent electrochemical performance for supercapacitors

A hierarchical flower-like β-NiS architecture has been successfully synthesized via a solvothermal method with diethanolamine as the coordination agent and solvent. When evaluated as an electrode material for supercapacitors, impressive electrochemical performances are achieved, with high specific discharge capacitances of 857.76 F g−1 at 2 A g−1 and 512.96 F g−1 at 5 A g−1.

General One-Pot Template-Free Hydrothermal Method to Metal Oxide Hollow Spheres and Their Photocatalytic Activities and Lithium Storage Properties

A general and facile one-pot template-free hydrothermal strategy has been developed to synthesize various metal oxide (TiO2, SnO2 and α-Fe2O3) hollow spheres with unified morphologies. The formation of hollow structure involves a trifluoroacetic acid (TFA)-assisted Ostwald ripening process. Photocatalytic activities of the as-prepared TiO2 product are evaluated by the photodegradation of Rhodamine B (RhB), which the TiO2 hollow spheres obtained from 450 °C thermal treatment exhibit higher photocatalytic activity than Degussa P25. In addition, electrochemical measurements demonstrate that all of the as-prepared metal oxides hollow spheres have the potential applications in lithium-ion battery. We have a great expectation that this synthesis strategy can afford a new universal route for functional metal oxide hollow materials preparation without using template.

Facile synthesis of novel α-Ag3VO4 nanostructures with enhanced photocatalytic activity

Novel α-Ag3VO4 nanostructures have been successfully synthesized via a facile and repeatable precipitation method by using n-BA as precipitant and complexing agent. Photocatalytic property tests for decomposition of RhB demonstrate that the as-prepared nanostructures have enhanced photocatalytic activity.

One-step extended strategy for the ionic liquid-assisted synthesis of Ni3S4–MoS2 heterojunction electrodes for supercapacitors

A convenient, self-assembly, ionic liquid-assisted method for the preparation of a Ni3S4–MoS2 heterojunction is reported. The Ni3S4 support not only provided high conductivity in the heterojunction for MoS2, but also showed more compatibility with MoS2, allowing a long cycle life. The capacity of the Ni3S4–MoS2 heterojunction is 985.21 F g−1 at a current density of 1 A g−1, and it can retain 573 F g−1 after 20 000 cycles at a current density of 10 A g−1. The Ni3S4–MoS2//AC (ASC) device demonstrated a high energy density of 58.43 W h kg−1 when the power density reached 385.95 W kg−1, and it can retain an energy density of 18.75 W h kg−1 even at a high power density of 7500 W kg−1, revealing its potential and viability for practical applications. Furthermore, this work provides a novel method to synthesize MxSy–MoS2 (M = Co, Mn, etc.) heterojunction materials in one step. These heterojunction materials could be used in a wide range of fields such as in HER catalysts, Li ion batteries and supercapacitor electrodes.

Interior design of three-dimensional CuO ordered architectures with enhanced performance for supercapacitors

Oriented assembly of low-dimensional building blocks into their higher order three-dimensional (3D) multifunctional architectures is a fascinating technique to improve the electrochemical performance of random low-dimensional materials. Here, we have successfully realized two 3D CuO ordered nanostructures (CONs) assembled by 1D and 2D building blocks via a facile solvothermal method with mixed solutions of deionized water and ethylene glycol (EG). The synergistic effect of EG and n-butylamine on the crystal nucleation and growth process dominates the fabrication of various 3D architectures. Compared with disorganized 2D nanoflakes, 3D CONs exhibit higher specific surface areas, more convenient electron and ion mobility, and greater structural stability, which contribute to the rapid and reversible redox reaction in pseudocapacitors. Impressively, the electrochemical characteristics are greatly improved by 3D CON electrodes, showing high specific capacitance (541 and 585 F g−1 at 1 A g−1), good rate capability (retaining 81% and 79% at 20 A g−1), and stable cycle life (85.3% and 86.8% capacitance retention after 8000 cycles). More importantly, the asymmetric supercapacitor based on 3D CONs expresses excellent cycling stability (85.3% capacitance retention after 10 000 cycles) and high energy density (31.47 W h kg−1 at a power density of 892 W kg−1). The design of the 3D porous ordered nanostructures would provide a novel and ideal approach for enhancing comprehensive performance of other electrode materials in energy conversion and storage fields.

Ionic liquid-assisted synthesis of mesoporous α-Ga2O3 hierarchical structures with enhanced photocatalytic activity

In this article, we successfully fabricate α-GaOOH hierarchical structures using a facile and simple one-pot ionic liquid-assisted hydrothermal method. In addition, the as-prepared α-GaOOH precursor can then be converted to mesoporous α-Ga2O3 hierarchical structures by thermal decomposition while preserving the same morphology, which exhibit enhanced photocatalytic activity.

Ionic liquid-assisted solvothermal synthesis of oriented self-assembled Fe3O4 nanoparticles into monodisperse nanoflakes

Self-assembled Fe3O4 nanoflakes have been synthesized via an ionic liquid-assisted solvothermal method. The obtained Fe3O4 nanoflakes are composed of well-aligned nanoparticles with an average diameter of about 15 nm. More importantly, the ionic liquid [C16mim]Cl (1-hexadecyl-3-methylimidazolium chloride) plays a critical role for the self-assembly of nanoparticles into nanoflakes by adsorbing onto the surfaces of the primary Fe3O4 nanoparticles.

Geometric Matching Principle for Adsorption Selectivity of Ionic Liquids: A Simple Method into the Fascinating World of Shape‐Controlled Chemistry

Ionic liquids (ILs) possess effective functions in controlling the phase and morphology of nanomaterials. However, it is still unclear how ILs affect the morphology control and what the origin of adsorption selectivity of ILs is on different crystal facets. It is a challenge to develop a simple method to select the suitable kinds of ILs for achieving the controllable synthesis of nanomaterials with designable shape. Herein, density functional theory (DFT) calculations were combined with experiment to study the interaction mechanism between ILs and crystal facets. An important relationship is proposed, named as the geometric matching principle, in which the adsorption site of substrate should not only need to meet the space requirement for interionic stacking of ILs, but also needs to maximize the interaction between adsorbed ILs and substrate. This new finding is meaningful for prediction of the adsorption selectivity of ILs and clarification of their shape-controlled chemistry.

Tensile force-induced tearing and collapse of ultrathin carbon shells to surface-wrinkled grape skins for high performance supercapacitor electrodes

With glucose as a highly accessible carbon source, mesoporous carbon nano grape skins were successfully fabricated via a facile template-based hydrothermal method and subsequent tensile force-induced tearing and collapse. The resulting carbon nano grape skins possess a novel structure as a nanosheet rolled up from the around, which maintains the ultrathin properties of the nanosheets. However, unlike carbon nanosheets, which are prone to aggregation or restacking, the carbon nano grape skins were separated from each other due to the crimp force induced by the rolled side. The largest specific surface area of 1570.9 m2 g−1 and the total pore volume of 2.429 m3 g−1 were achieved for the product obtained at 600 °C. Compared to carbon nanosheets and carbon hollow spheres obtained at 700 °C, the products obtained at 700 °C, when used as electrode materials for supercapacitors, showed a much higher specific capacitance of 268 F g−1 at 0.1 A g−1, a higher rate specific capacitance of 170 F g−1 at 10 A g−1, and better cycling stability with 94.2% capacitance retention after 10 000 cycles at 2 A g−1 in a two-electrode system.

Ni/Ni3C Core/Shell Hierarchical Nanospheres with Enhanced Electrocatalytic Activity for Water Oxidation

Developing efficient and low-cost catalysts with high activity and excellent electrochemical and structural stability toward the oxygen evolution reaction (OER) is of great significance for both energy and environment sustainability. Herein, Ni/Ni3C core/shell hierarchical nanospheres have been in situ synthesized via an ionic liquid-assisted hydrothermal method at relatively low temperature. Ionic liquid 1-butyl-3-methylimidazolium acetate has played multiple roles in the whole synthesis process. Benefiting from the high electrical conductivity, more exposed active sites and the core/shell interface effect, the obtained Ni/Ni3C core/shell hierarchical nanospheres exhibit an outstanding OER performance with lower overpotential, small Tafel slope, and excellent stability. This fundamental method and insights with in situ coupling high conductivity metal support and metal carbide in a core/shell nanoarchitecture by an ionic liquid-assisted hydrothermal method would open up a new pathway to achieve high-performance electrocatalysts toward the OER.