Hierarchical Nanosheets Research Articles

Design of porous FeNi-carbon nanosheets by a double-effect synergistic strategy for electromagnetic wave absorption

The electromagnetic pollution problem caused by the wide application of electromagnetic waves has seriously affected human life and prompted people to research efficient electromagnetic absorption materials. In this work, a porous FeNi-carbon nanosheet was designed and synthesized by a double-effect synergistic strategy. The three raw materials achieved perfect structural synergy, organically combining the magnetic medium with carbon materials. FeNi nanoparticles are evenly distributed on hierarchical pore carbon nanosheets. This unique structure dramatically reduces the materials’ density and improves impedance matching. The minimum density of porous FeNi-carbon nanosheets (FeNi-CNSs) is 36.3 mg cm3, comparable to that of carbon aerogels. More importantly, the synergistic attenuation mechanism of dielectric loss and magnetic loss promotes the efficient attenuation of FeNi-CNSs to electromagnetic waves. The minimum reflection loss (RLmin) of FeNi-CNSs is −47.27 dB at 3.0 mm, and the effective absorption bandwidth (EAB) is as high as 7.1 GHz at 2.5 mm. More surprisingly, when the thickness is in the range of 1.8–3.0 mm, the average EAB reaches 6.22 GHz, which expands the operational range of practical applications and provides the possibility for the application and promotion of lightweight magnetic carbon nanosheet microwave absorbing materials.

Flexible High Energy Density Sodium Dual‐ion Battery with Long Cycle life

Flexible fiber‐shaped sodium dual‐ion batteries (FSDIBS) as a proof of concept are fabricated by using the hierarchical ReS2 nanosheets anchored on the carbon nanotube (ReS2@CNT) fiber as anode and graphite on the CNT as cathode. Owing to large interlayer spacing and weak layer coupling force of the ReS2 nanosheets and the anion accommodation of the graphite combined with good flexibility of the CNT fiber, the FSDIBS demonstrate outstanding electrochemical performances with high working voltage and high specific volumetric energy density, durable cycling life, and good flexibility. The FSDIBS show a specific discharge capacity of 97.8 mAh cm−3 at a current density of 630 mA cm−3 and high specific energy density of 25.12 mWh cm−3 (based on the whole volume of the two electrodes) and superb stability with a capacity retention of 91.8% even after bending for 2100 cycles. Moreover, a series of ex situ/in situ characterizations are verified that the reversible shuttles of the Na+ cations and anions between the anode and cathode are simultaneously occurred during the charge/discharge process.

Facile synthesis of hierarchical SnSe nanosheets–hydrogel evaporators for sustainable solar-powered desalination

A facile method based on the Rayleigh–Bénard convection was developed to synthesize hierarchical SnSe nanosheets–hydrogel evaporators, which have potential applications in sustainable solar-powered desalination due to their excellent water-evaporation performance.

Hierarchical porous transition metal oxide nanosheets templated from waste bagasse: General synthesis and Li/Na storage performance

As a promising anode candidate, hierarchical porous transition metal oxide nanosheets (TMO-NSs) have attracted significant interest due to their various advantages of abundant active sites, high specific capacity and shortened ion/electrons transport pathways. Although the TMO-NSs have been developed in the past decades, the previous synthesis strategies have some drawbacks such as high cost, complex synthesis techniques, and the requirement of special instruments. Herein, we develop a generalized and facile biomorphic method to synthesize various controllable hierarchical porous TMO-NSs by using waste bagasse as biotemplate. Furthermore, the porosity and pore size of as-prepared hierarchical porous TMO-NSs can be adjusted by changing the precursor solution concentration. Novel hierarchical porous TMO-NSs have been successfully prepared for many ternary or binary TMO, such as NiFe 2 O 4 , ZnFe 2 O 4 , ZnMn 2 O 4 , NiO and ZnO. Owing to their unique nanostructure, as-synthesized hierarchical porous TMO-NSs show an excellent electrochemical performance when used as anode for Li/Na-ion batteries. We believe that various hierarchical porous TMO-NSs available from the green, economical and convenient biomorphic strategy may lead to further developments in research and application on TMO-NSs materials.

Interconnected Hierarchical Porous Carbon Nanosheets Derived from Renewable Biomass for Efficient Oxygen Evolution Reaction

Interconnected Hierarchical Porous Carbon Nanosheets Derived from Renewable Biomass for Efficient Oxygen Evolution Reaction

CeO2 decorated on Co-ZIF-L-derived nickel-cobalt sulfide hollow nanosheet arrays for high-performance supercapacitors.

Transition metal sulfides have been widely explored as electrode materials for supercapacitors. Unfortunately, the slow redox reaction kinetics and severe volume changes during charge/discharge result in compromised electrochemical performance. In this work, a nickel-cobalt sulfide hollow nanosheet array decorated with cerium oxide nanoparticles (NiCoS/CeO2) has been constructed using a cobalt zeolitic imidazolate framework-L as the template coupled with subsequent solvothermal synthesis. Benefiting from the advantages of the hollow and hierarchical NiCoS nanosheets with a large number of accessible active sites and fast charge transport pathways, as well as CeO2 layers with rich oxygen vacancies and strong interaction between NiCoS and CeO2, NiCoS/CeO2 exhibits a high specific capacity of 1278.1 C g-1 (1 A g-1), which is approximately 1.9 times that of NiCoS. The asymmetric supercapacitor assembled using NiCoS/CeO2 and activated carbon shows an excellent storage capability (34.9 W h kg-1 at 850.0 W kg-1) and an impressive cycle life (91.9% capacitance retention after 10 000 charge and discharge cycles at 10 A g-1).

Rational design of double-shelled Cu2MoS4@N-doped carbon hierarchical nanoboxes toward fast and stable sodium-ion batteries

Double-shelled Cu2MoS4@NC nanoboxes, composed of an outer shell of N-doped carbon supported on the inner shell of hierarchical Cu2MoS4 nanosheets, are synthesized by a delicate template-based strategy and exhibit enhanced sodium storage performance.

Self-assembled hierarchical metal–polyphenol-coordinated hybrid 2D Co–CTA@g-C3N4heterostructured nanosheets for efficient electrocatalytic oxygen reduction

We exquisitely designed thein situgrowth of Co nanoparticles coated with tannin-carbon embedded on the hierarchical ultrathin g-C3N4nanosheets for boosting electrocatalytic oxygen reduction through the MPNs strategy.

An Integrated Cathode Engineered by Hierarchical Honeycomb-Like Copper-Molybdenum Sulfide Nanosheets for Hybrid Supercapacitor with Improved Energy Storage Capability

An Integrated Cathode Engineered by Hierarchical Honeycomb-Like Copper-Molybdenum Sulfide Nanosheets for Hybrid Supercapacitor with Improved Energy Storage Capability

3D hierarchical cobalt vanadate nanosheet arrays on Ni foam coupled with redox additive for enhanced supercapacitor performance.

Room-temperature synthesized 3D hierarchical cobalt vanadate (Co3V2O8) nanosheet arrays on Ni foam for use as supercapacitor electrode is presented. In a 3 M KOH electrolyte, the electrode exhibits a capacitance of 109.9 mA h g-1 (878.9 F g-1) at a current density of 1 A g-1. The capacitance is enhanced to 198.1 mA h g-1 (1584.5 F g-1) at 1 A g-1 through the addition of 0.05 M redox-additive K3[Fe(CN)6] into the KOH electrolyte. Furthermore, the Co3V2O8/activated carbon asymmetric supercapacitor cell with the advanced electrolyte outperforms most reported Co3V2O8-based electrodes with a remarkable energy density of 55.5 W h kg-1 at an 800 W kg-1 power density. Combining a facile synthetic strategy and excellent electrochemical performance, the obtained Co3V2O8 exhibits potential for practical application.

Boosting the energy storage performance of MOF-derived Co3S4 nanoarrays via sulfur vacancy and surface engineering.

Hierarchical Co3S4 hollow nanosheet arrays are prepared through a MOF-engaged strategy, followed by room-temperature NaBH4 treatment, resulting in simultaneous regulation of sulfur vacancies and surface morphology. The obtained electrode exhibits excellent electrochemical properties due to large active sites, fast charge diffusion and high electronic conductivity resulting from the hierarchical hollow structure and rich sulfur vacancies.

Construction of Hierarchical Copper-Based Metal-Organic Frameworks Nanosheet Assemblies as an Efficient Electrocatalyst

Construction of Hierarchical Copper-Based Metal-Organic Frameworks Nanosheet Assemblies as an Efficient Electrocatalyst

An Integrated Cathode Engineered by Hierarchical Honeycomb-Like Copper-Molybdenum Sulfide Nanosheets for Hybrid Supercapacitor with Improved Energy Storage Capability

An Integrated Cathode Engineered by Hierarchical Honeycomb-Like Copper-Molybdenum Sulfide Nanosheets for Hybrid Supercapacitor with Improved Energy Storage Capability

An Integrated Cathode Engineered by Hierarchical Honeycomb-Like Copper-Molybdenum Sulfide Nanosheets for Hybrid Supercapacitor with Improved Energy Storage Capability

An Integrated Cathode Engineered by Hierarchical Honeycomb-Like Copper-Molybdenum Sulfide Nanosheets for Hybrid Supercapacitor with Improved Energy Storage Capability

Pd/Ni-metal-organic framework-derived porous carbon nanosheets for efficient CO oxidation over a wide pH range.

Metal nanocrystal ornamented metal-organic frameworks (MOFs) are of particular interest in multidisciplinary applications; however, their electrocatalytic CO oxidation performance over wide pH ranges is not yet reported. Herein, Ni-MOF-derived hierarchical porous carbon nanosheets (Ni-MOF/PC) with abundant Ni-N x sites decorated with Pd nanocrystals (Pd/Ni-MOF/PC) were synthesized by microwave-irradiation (MW-I) followed by annealing at 900 °C and subsequent etching of Ni-MOF/C prior to Pd deposition. The fabrication mechanism comprises the generation of self-reduced reducing gases from triethylamine during the annealing and selective chemical etching of Ni, thereby facilitating the reduction of Ni-anchored MOF and Pd nanocrystal deposition with the aid of ethylene glycol and MW-I to yield Pd/Ni-N x enriched MOF/PC. The synthetic strategies endear the Pd/Ni-MOF/PC with unique physicochemical merits: abundant defects, interconnected pores, high electrical conductivity, high surface area, Ni-deficient but more active sites for Pd/Ni-N x in porous carbon nanosheets, and synergism. These merits endowed the CO oxidation activity and stability on Pd/Ni-MOF/PC substantially than those of Pd/Ni-MOF/C and Pd/C catalysts in wide pH conditions (i.e., KOH, HClO4, and NaHCO3). The CO oxidation activity study reveals the utilization of MOF/PC with metal nanocrystals (Pd/Ni) in CO oxidation catalysis.

Spontaneous Formation of Nitrogen - Doped Hierarchical Porous Microcrystalline Nanosheets with Improved Co2 Capture at Low and Medium Pressures

Spontaneous Formation of Nitrogen - Doped Hierarchical Porous Microcrystalline Nanosheets with Improved Co2 Capture at Low and Medium Pressures

Urchin-like hierarchical ruthenium cobalt oxide nanosheets on Ti3C2Tx MXene as a binder-free bifunctional electrode for overall water splitting and supercapacitors.

Synthesizing efficient electrode materials for water splitting and supercapacitors is essential for developing clean electrochemical energy conversion/storage devices. In the present work, we report the construction of a ruthenium cobalt oxide (RuCo2O4)/Ti3C2Tx MXene hybrid by electrophoretic deposition of Ti3C2Tx MXene on nickel foam (NF) followed by RuCo2O4 nanostructure growth through an electrodeposition process. Owing to the strong interactions between RuCo2O4 and Ti3C2Tx sheets, which are verified by density functional theory (DFT)-based simulations, RuCo2O4/Ti3C2Tx MXene@NF can serve as a bifunctional electrode for both water splitting and supercapacitor applications. This electrode exhibits outstanding electrocatalytic activity with low overpotentials of 170 and 68 mV at 100 A m-2 toward the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The RuCo2O4/Ti3C2Tx MXene@NF-based alkaline water-splitting cell only requires 1.62 V to achieve a current density of 100 A m-2, which is much better than that of RuO2@NF and Pt/C@NF-assembled cells (1.75 V@100 A m-2). The symmetric supercapacitor (SSC)-assembled electrode displays a high specific capacitance of 229 F g-1 at 3 A g-1. The experimental results, complemented with theoretical insights, provide an effective strategy to prepare multifunctional materials for electrocatalysis and energy storage applications.

Micro-Meso Hierarchical Porous Ultrathin Nitrogen-Doped Carbon Nanosheets with Rough Surfaces for Efficient Gas Adsorption and Separation

Micro-Meso Hierarchical Porous Ultrathin Nitrogen-Doped Carbon Nanosheets with Rough Surfaces for Efficient Gas Adsorption and Separation

3d Hierarchical Cobalt Vanadate Nanosheet Arrays on Ni Foam Coupled with Redox Additive for Enhanced Supercapacitor Performance

3d Hierarchical Cobalt Vanadate Nanosheet Arrays on Ni Foam Coupled with Redox Additive for Enhanced Supercapacitor Performance

MOF-derived N-doped ZnO carbon skeleton@hierarchical Bi2MoO6 S-scheme heterojunction for photodegradation of SMX: Mechanism, pathways and DFT calculation

Semiconductor photocatalytic degradation of pollutants is considered to be one of the promising sustainable energy routes. Nevertheless, it is challenging for photocatalysts to have excellent visible light absorption and suppress photo-generated electron-hole recombination at the same time. Here, we prepared nitrogen-doped ZnO carbon skeleton by directly calcining the metal-organic framework. Then hierarchical Bi2MoO6 nanosheets are grown in situ on its surface to synthesize S-scheme heterojunction. This special 3D layered and oxygen vacancies work together to make photo-generated electrons and holes easier to separate and migrate. Therefore, the pseudo-first-order kinetic constant of N-doped ZnO carbon skeleton@Bi2MoO6 degradation of sulfamethoxazole reaches 0.022 min–1, which is almost 10 times that of ZIF-8 derived ZnO and 27.5 times Bi2MoO6 under visible light irradiation. Meanwhile, the mechanism of driving charge transfer of S-scheme heterojunction, and the photocatalytic degradation pathway of sulfamethoxazole are also analyzed. This work will provide a new way to construct S-scheme heterojunction photocatalyst to degrade antibiotic pollutants.