Tunable heteroassembly of 2D CoNi LDH and TiC nanosheets with enhanced electrocatalytic activity for oxygen evolution.

The sluggish kinetics of the oxygen evolution reaction (OER) is the bottleneck to developing hydrogen energy based on water electrolysis, which can be significantly improved using high performance catalysts. In this context, CoNi layered double hydroxide (LDH)/TiC heterostructures are obtained using electrostatic attraction of the positively charged LDH and negatively charged TiC nanosheets as the catalyst to optimize the OER performance. Such alternate stacking exhibits good catalytic activity with a lower overpotential and a small Tafel slope, outperforming their individual components.

Two-dimensional nanomaterials based on rare earth elements for biomedical applications.

As a kind of star materials, two-dimensional (2D) nanomaterials have attracted tremendous attention for their unique structures, excellent performance and wide applications. In recent years, layered rare earth-based or doped nanomaterials have become a new important member of the 2D nanomaterial family and have attracted significant interest, especially layered rare earth hydroxides (LREHs) and layered rare earth-doped perovskites with anion-exchangeability and exfoliative properties. In this review, we systematically summarize the synthesis, exfoliation, fabrication and biomedical applications of 2D rare earth nanomaterials.

Systematic Study on Swelling/Delamination of Layered Metal Oxides with Quaternary Ammonium Ions: Production of Well-Shaped/Oversized Unilamellar Nanosheets.

Enormous swelling of layered host compounds in an aqueous solution of various amines has been investigated as an important step in the synthesis of molecularly thin 2D nanosheets. However, a complete understanding of the reaction process has not been attained, which is the barrier for producing high-quality unilamellar nanosheets. Here, the swelling and delamination behaviors of platelet single crystals of protonated layered metal oxides are systematically examined with a series of tetraalkylammonium (TAA) hydroxide solutions.

Metal-Organic Framework on Fullerene (MOFOF) as a Hierarchical Composite by the Integration of Coordination Chemistry and Supramolecular Chemistry.

There is a synergy between coordination chemistry and supramolecular chemistry that has led to the development of innovative hierarchical composites with diverse functionalities. Here, we present a novel approach for the synthesis and characterization of a metal-organic framework on fullerene (MOFOF) composites, achieved through the integration of coordination chemistry and supramolecular chemistry principles. The hierarchical nature of the MOFOF harnesses the inherent properties of metal-organic frameworks and fullerenes.

Tunable Pt-NiO interaction-induced efficient electrocatalytic water oxidation and methanol oxidation.

Metal-support interaction engineering is considered an efficient strategy for optimizing the catalytic activity. Nevertheless, the fine regulation of metal-support interactions as well as understanding the corresponding catalytic mechanisms (particularly those of non-carbon support-based counterparts) remains challenging. Herein, a controllable adsorption-impregnation strategy was proposed for the preparation of a porous nonlayered 2D NiO nanoflake support anchored with different forms of Pt nanoarchitectures, single atoms, clusters and nanoparticles.

Covalently bridging graphene edges for improving mechanical and electrical properties of fibers.

Assembling graphene sheets into macroscopic fibers with graphitic layers uniaxially aligned along the fiber axis is of both fundamental and technological importance. However, the optimal performance of graphene-based fibers has been far lower than what is expected based on the properties of individual graphene. Here we show that both mechanical properties and electrical conductivity of graphene-based fibers can be significantly improved if bridges are created between graphene edges through covalent conjugating aromatic amide bonds.

Perovskite CoSn(OH) nanocubes with tuned d-band states towards enhanced oxygen evolution reactions.

The CoSn(OH) perovskite hydroxide is a structure stable and inexpensive electrocatalyst for the oxygen evolution reaction (OER). However, the OER activity of CoSn(OH) is still unfavorable due to its limited active sites. In this work, an Fe doping strategy is used to optimize the d-band state of the CoSn(OH) perovskite hydroxide.

Crystal Structure Regulation of CoSe Induced by Fe Dopant for Promoted Surface Reconstitution toward Energetic Oxygen Evolution Reaction.

Most nonoxide catalysts based on transition metal elements will inevitably change their primitive phases under anodic oxidation conditions in alkaline media. Establishing a relationship between the bulk phase and surface evolution is imperative to reveal the intrinsic catalytic active sites. In this work, it is demonstrated that the introduction of Fe facilitates the phase transition of orthorhombic CoSe into its cubic counterpart and then accelerates the Co-Fe hydroxide layer generation on the surface during electrocatalytic oxygen evolution reaction (OER).

Mild selective photochemical oxidation of an organic sulfide using OxP-polyimide porous polymers as singlet oxygen generators.

A series of porous organic polymers based on a singlet oxygen generating oxoporphyinogen ('') has been successfully prepared from a pseudotetrahedral -tetraamine precursor () by its reaction with tetracarboxylic acid dianhydrides under suitable conditions. Of the compounds studied, those containing naphthalene () and perylene () spacers, respectively, have large surface areas (~530 m g). On the other hand, the derivative with a simple benzene spacer () exhibits the best O generating capability.

Multiple Cations Nanoconfinement in Ultrathin VO Nanosheets Enables Ultrafast Ion Diffusion Kinetics Toward High-performance Zinc Ion Battery.

Nanoconfinement of cations in layered oxide cathode is an important approach to realize advanced zinc ion storage performance. However, thus far, the conventional hydrothermal/solvothermal route for this nanoconfinement has been restricted to its uncontrollable phase structure and the difficulty on the multiple cation co-confinement simultaneously. Herein, this work reports a general, supramolecular self-assembly of ultrathin VO nanosheets using various unitary cations including Na, K, Mg, Ca, Zn, Al, NH , and multiple cations (NH + Na, NH + Na + Ca, NH + Na + Ca +Mg).

Construction of Hierarchical Films via Layer-by-Layer Assembly of Exfoliated Unilamellar Zeolite Nanosheets.

Zeolites have been widely applied as versatile catalysts, sorbents, and ion exchangers with unique porous structures showing molecular sieving capability. In these years, it is reported that some layered zeolites can be delaminated into molecularly thin 2-dimensional (2D) nanosheets characterized by inherent porous structures and highly exposed active sites. In the present study, two types of zeolite nanosheets with distinct porous structures with MWW topology (denoted mww) and ferrierite-related structure (denoted bifer) are deposited on a substrate through the solution process via electrostatic self-assembly.

Tungsten Nitride/Tungsten Oxide Nanosheets for Enhanced Oxynitride Intermediate Adsorption and Hydrogenation in Nitrate Electroreduction to Ammonia.

Electrochemical NO reduction reaction (NORR) is a promising technique for green NH synthesis. Tungsten oxide (WO) has been regarded as an effective electrocatalyst for electrochemical NH synthesis. However, the weak adsorption and the sluggish hydrogenation of oxynitride intermediates (NO, e.

Heterointerface engineering of NiFe (oxy)hydroxides/CNTs by anchoring of sub-nano Au for efficient water oxidation.

Heterointerface engineering of NiFe (oxy)hydroxides is a prospective way of improving OER activity by the pre-catalysis of metal hydroxides accompanying the modulation of defects, but enhancement of the kinetics is controversial. Herein, phase transformation of NiFe hydroxides was proposed and heterointerface engineering was optimized by sub-nano Au anchoring in simultaneously formed cation vacancies. Controllable size and concentrations of anchored sub-nano Au in the cation vacancies resulted in the modulation of the electronic structure at the heterointerface, and improved water oxidation activity was ascribed to the enhanced intrinsic activity and charge transfer rate.

Advanced Pt-based electrocatalysts for the hydrogen evolution reaction in alkaline medium.

Water electro-splitting driven by renewable energy is significant in energy conversion for the development of hydrogen energy sources. The hydrogen evolution reaction (HER) directly generating hydrogen products occurs in cathode catalysis. Over the years, significant progress has been made to boost the HER efficiency by exploratively designing highly active and economical Pt-based electrocatalysts.

Porous and Partially Dehydrogenated Fe -Containing Iron Oxyhydroxide Nanosheets for Efficient Electrochemical Nitrogen Reduction Reaction (ENRR).

The design and development of efficient catalysts for electrochemical nitrogen reduction reaction (ENRR) under ambient conditions are critical for the alternative ammonia (NH ) synthesis from N and H O, wherein iron-based electrocatalysts exhibit outstanding NH formation rate and Faradaic efficiency (FE). Here, the synthesis of porous and positively charged iron oxyhydroxide nanosheets by using layered ferrous hydroxide as a starting precursor, which undergoes topochemical oxidation, partial dehydrogenated reaction, and final delamination, is reported. As the electrocatalyst of ENRR, the obtained nanosheets with a monolayer thickness and 10-nm mesopores display exceptional NH yield rate (28.

CNT-MXene ultralight membranes: fabrication, surface nano/microstructure, 2D-3D stacking architecture, ion-transport mechanism, and potential application as interlayers for Li-O batteries.

Multiwalled carbon nanotubes (MWCNTs) have shown effectiveness in improving the suitability of MXenes for energy-related applications. However, the ability of individually dispersed MWCNTs to control the structure of MXene-based macrostructures is unclear. Here, the correlation among composition, surface nano- and microstructure, MXenes' stacking order, structural swelling, and Li-ion transport mechanisms and properties in individually dispersed MWCNT-TiC films was investigated.

Reversible Ammonium Ion Intercalation/de-intercalation with Crystal Water Promotion Effect in Layered VOPO ⋅2 H O.

The non-metal NH carrier has attracted tremendous interests for aqueous energy storage owing to its light molar mass and fast diffusion in aqueous electrolytes. Previous study inferred that NH ion storage in layered VOPO ⋅2 H O is impossible due to the removal of NH from NH VOPO leads to a phase change inevitably. Herein, we update this cognition and demonstrated highly reversible intercalation/de-intercalation behavior of NH in layered VOPO ⋅2 H O host.

Advanced hematite nanomaterials for newly emerging applications.

Because of the combined merits of rich physicochemical properties, abundance, low toxicity, , hematite (α-FeO), one of the most chemically stable compounds based on the transition metal element iron, is endowed with multifunctionalities and has steadily been a research hotspot for decades. Very recently, advanced α-FeO materials have also been developed for applications in some cutting-edge fields. To reflect this trend, the latest progress in developing α-FeO materials for newly emerging applications is reviewed with a particular focus on the relationship between composition/nanostructure-induced electronic structure modulation and practical performance.

Synthesis of a Hexagonal Phase ZnS Photocatalyst for High CO Selectivity in CO Reduction Reactions.

ZnS materials exhibit very negative potential of the conduction band, which is promising in photocatalytic reduction reactions. Unfortunately, previously reported ZnS materials for photocatalysis are mainly in the cubic phase, which produce high activity for H evolutions and low activity toward CO reductions. Herein, a hexagonal phase ZnS photocatalyst is fabricated for highly efficient CO reduction reactions.

Nanoporous Hollow Carbon Spheres Derived from Fullerene Assembly as Electrode Materials for High-Performance Supercapacitors.

The energy storage performances of supercapacitors are expected to be enhanced by the use of nanostructured hierarchically micro/mesoporous hollow carbon materials based on their ultra-high specific surface areas and rapid diffusion of electrolyte ions through the interconnected channels of their mesoporous structures. In this work, we report the electrochemical supercapacitance properties of hollow carbon spheres prepared by high-temperature carbonization of self-assembled fullerene-ethylenediamine hollow spheres (FE-HS). FE-HS, having an average external diameter of 290 nm, an internal diameter of 65 nm, and a wall thickness of 225 nm, were prepared by using the dynamic liquid-liquid interfacial precipitation (DLLIP) method at ambient conditions of temperature and pressure.

Lithiophilic and Anticorrosive Cu Current Collector via Dual-Bonded Porous Polymer Coating for Stable Lithium-Metal Batteries.

Li metal is the ultimate anode material for next-generation high-energy-density rechargeable batteries. However, the uncontrollable growth of Li dendrites and low Coulombic efficiency (CE) prevent it from practical applications in Li metal batteries (LMBs). Here, a facile and low-cost strategy is developed to decorate a Cu current collector with a self-assembled γ-aminopropyltrimethoxysilane (γ-APS) film.

Seed-Derived Hierarchically Porous Carbon Materials for High-Performance Supercapacitor Applications.

The electrical double-layer supercapacitance performance of the nanoporous carbons prepared from the (Amala) seed by chemical activation using the potassium hydroxide (KOH) activator is reported. KOH activation was carried out at different temperatures (700-1000 °C) under nitrogen gas atmosphere, and in a three-electrode cell set-up the electrochemical measurements were performed in an aqueous 1 M sulfuric acid (HSO) solution. Because of the hierarchical pore structures with well-defined micro- and mesopores, seed-derived carbon materials exhibit high specific surface areas in the range of 1360 to 1946 m g, and the total pore volumes range from 0.

Review on recent progress in WO-based electrochromic films: preparation methods and performance enhancement strategies.

Transition metal oxides have drawn tremendous interest due to their unique physical and chemical properties. As one of the most promising electrochromic (EC) materials, tungsten trioxide (WO) has attracted great attention due to its exceptional EC characteristics. This review summarizes the background and general concept of EC devices, and key criteria for evaluation of WO-based EC materials.