As-obtained 3D Research Articles

Carbon dots as reductants to fabricate three-dimensional Au mesoflowers as SERS substrates

Abstract Reductive carbon dots (CDs) were obtained by a hydrothermal method using citric acid and diethylenetriamine as carbon sources. Three-dimensional Au mesoflowers (3D Au MFs) could be fabricated by directly mixing HAuCl4 and CD solution without using any extra reductant and morphology-directing reagent. The as-obtained 3D Au MFs exhibited high surface-enhanced Raman spectroscopy (SERS) activity in detection of methylene blue.

3D porous sponge-like sensors prepared from various conductive nanohybrids-filled melamine sponge toward human motion detections

Melamine sponge (MS) is a commercial material with low density, high porosity, and superior elasticity, which has been utilized to design and produce three‐dimensional (3D) porous sponge-like sensors. Notably, this material is environment‐friendly and inexpensive. In the present study, an MS filled with various hybrid source bridges, as 3D porous sponges, was designed and prepared by using a simple and low-cost immerse-filling method and then submerged into various hybrid source mixtures with the support of an MS framework with a hole-opened structure. The structurally morphological, chemical, thermal, and mechanical properties of the as-obtained 3D porous sponges were further determined for potential changes in the structure of these sponges after filling the hybrid source mixtures in/on the MS framework. The presence of functional hybrid sources in the 3D porous sponges indicated that such sponges have reached a good sensitivity, stretch ability, and repeatability under compressing, stretching, bending, and twisting deformations. In addition, these sponges were effectively applied for detecting and monitoring concomitantly small- and large-scale movements of the human body, that is, the various motions of the knee, elbow, finger, wrist, and foot insole. Therefore, the 3D porous sponges prepared in this study can be considered as a promising candidate for practical applications as flexible or wearable devices.

Constructing a 3D crumpled MXene host for high-performance lithium metal anode

Lithium metal anode is aroused widespread attention because of its high specific capacity and the lowest reduction potential. However, the commercial application of lithium metal anode is impeded by the uncontrollable growth of lithium dendrite and low Coulombic efficiency (CE). Herein, we construct a three-dimensional (3D) crumpled MXene (C-MXene) sheets host for advanced composite lithium metal anode, where the C-MXene sheets are prepared by a co-solvent freeze drying method. Benefiting from the unique properties of high electronic conductivity, rich lithium nucleation sites, and the continuously porous structure, such C-MXene host delivers a high cycling stability and low over-potential at a high current density of 5.0 mA cm−2 with a deposition capacity of 3.0 mAh cm−2. Furthermore, a full lithium metal cell is constructed with the as-obtained 3D C-MXene@Li anode and LiFePO4 (LFP) cathode, which shows excellent rate and cycling performance.

Room-Temperature Magnetism in 2D MnGa4 -H Induced by Hydrogen Insertion.

2D room-temperature magnetic materials are of great importance in future spintronic devices while only very few are reported. Herein, a plasma-enhanced chemical vapor deposition approach is exploited to construct the 2D room-temperature magnetic MnGa4 -H single crystal with a thickness down to 2.2nm. The employment of H2 plasma makes hydrogen atoms can be easily inserted into the MnGa4 lattice to modulate the atomic distance and charge state, thereby ferrimagnetism can be achieved without destroying the structural configuration. The as-obtained 2D MnGa4 -H crystal is high-quality, air-stable, and thermo-stable, demonstrating robust and stable room-temperature magnetism with a high Curie temperature above 620K. This work enriches the 2D room-temperature magnetic family and opens up the possibility for the development of spintronic devices based on 2D magnetic alloys.

Ultrafast Charge Transfer 2D MoS2 /Organic Heterojunction for Sensitive Photodetector.

The 2D MoS2 with superior optoelectronic properties such as high charge mobility and broadband photoresponse has attracted broad research interests in photodetectors (PD). However, due to the atomic thin layer of 2D MoS2 , its pure photodetectors usually suffer from inevitable drawbacks such as large dark current, and intrinsically slow response time. Herein, a new organic material BTP-4F with high mobility is successfully stacked with 2D MoS2 film to form an integrated 2D MoS2 /organic P-N heterojunction, facilitating efficient charge transfer as well as significantly suppressed dark current. As a result, the as-obtained 2D MoS2 /organic (PD) has exhibited excellent response and fast response time of 332/274 µs. The analysis validated photogenerated electron transition from this monolayer MoS2 to subsequent BTP-4F film, whereas the transited electron is originated from the A- exciton of 2D MoS2 by temperature-dependent photoluminescent analysis. The ultrafast charge transfer time of ≈0.24ps measured by time-resolved transient absorption spectrum is beneficial for efficient electron-hole pair separation, greatly contributing to the obtained fast photoresponse time of 332/274 µs. This work can open a promising window to acquire low-cost and high-speed (PD).

Coupling Nonstoichiometric Zn0.76Co0.24S with NiCo2S4 Composite Nanoflowers for Efficient Synergistic Electrocatalytic Oxygen and Hydrogen Evolution Reactions

Transition-metal sulfide-based composite nanomaterials have garnered extensive interest not only for their unique morphological architectures but also for exploring as a noble-metal-free cost-effective, durable, and highly stable catalyst for electrochemical water splitting. In this work, we synthesized in situ nonstoichiometric Zn0.76Co0.24S with NiCo2S4 binary composite flowers (Zn0.76Co0.24S/NiCo2S4) in one step by thermal decomposition of Zn2[PDTC]4 and Ni[PDTC]2 complexes by a solvothermal process in a nonaqueous medium from their molecular precursor, and their potential application in electrochemical oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) was investigated. Field-emission scanning electron microscopy and transmission electron microscopy analyses revealed the flower-shaped morphology of as-synthesized Zn0.76Co0.24S/NiCo2S4. Again, the structural and chemical compositions were confirmed through powder X-ray diffraction and X-ray photoelectron spectroscopy studies, respectively. The as-obtained 3D flower-type Zn0.76Co0.24S/NiCo2S4 nanostructure was further subject to electrochemical OER and HER in alkaline and acidic media, respectively. Zn0.76Co0.24S/NiCo2S4 showed low overpotential values of 248 mV (Tafel slope, 85 mV dec–1) and 141 mV (Tafel slope, 79 mV dec–1) for OER and HER activities, respectively, due to the synergistic effects of Zn0.76Co0.24S and NiCo2S4. Several long-term stability tests also affirmed that the Zn0.76Co0.24S/NiCo2S4 composite nanostructure is a highly stable and efficient electrocatalyst toward OER and HER activities as compared to the recently reported superior bifunctional electrocatalysts as well as state-of-the-art materials.

A Three-Dimensional Silicon-Diacetylene Porous Organic Radical Polymer

A Three-Dimensional Silicon-Diacetylene Porous Organic Radical Polymer

Boosting catalytic performance of hierarchical Co/Co0.85Se microspheres via Mott-Schottky effect toward triiodide reduction and alkaline hydrogen evolution

Interface engineered composites composing of metal and transition metal selenides have been deemed as promising substitutes as noble Pt in the fields of the energy conversion. Herein, the well-defined hierarchical Co/Co 0.85 Se microsphere with Mott-Schottky (M-S) effect was synthesized by the facile solvothermal method (Co/Co 0.85 Se-3). Interestingly, the as-obtained 3D Co 0.85 Se microsphere was assembled by 2D porous nanosheets. The characteristics including M-S heterojunction and hierarchical structure endows Co/Co 0.85 Se microsphere with high specific surface area, good conductivity, and synergistic effect between metal Co and Co 0.85 Se. More concretely, the optimized Co/Co 0.85 Se exhibits outstanding catalytic activity toward triiodide reduction reaction (IRR). When employed as the counter electrode (CE) catalyst for dye-sensitized solar cell (DSSC), a photoelectric conversion efficiency (PCE) of 8.31 % is achieved, which is 3.36 % higher than that of Pt-control device (8.04 %). Moreover, Co/Co 0.85 Se-3 displays remarkable catalytic activity for hydrogen evolution reaction (HER) with a low overpotential of 107 mV at the current density of 10 mA cm −2 under alkaline condition (1.0 M KOH), accompanying with Tafel slope of 140 mV dec −1 . Our discovery provides an effective approach to develop the cost-effective advanced catalysts to promote the application of DSSC and HER. The hierarchical Co/Co 0.85 Se microspheres with unique Mott-Schottky structure exhibited excellent catalytic performance in the fields of DSSC and HER. • Hierarchical Co/Co 0.85 Se microsphere with M-S effect was synthesized. • Synergy between Co and Co 0.85 Se increases the catalytic activity of Co/Co 0.85 Se-3. • Performance of Co/Co 0.85 Se-3 for DSSC was higher than that of Pt. • Co/Co 0.85 Se-3 exhibited remarkable catalytic property for alkaline HERs.

CTAB-assisted construction of 3D flower-sphere S-scheme Bi12O17Br2/Bi4O5Br2 heterojunction with enhanced visible-light photocatalytic performance

In this study, novel 3D flower-sphere S-scheme Bi12O17Br2/Bi4O5Br2 heterojunction was successfully synthesized at room temperature through a facile co-precipitation method. As the morphology controlling reagent and bromine resource, cetyltrimethylammonium bromide (CTAB) surfactant played significant roles in Bi12O17Br2/Bi4O5Br2 crystal growth and heterostructure construction. The BB-10 (Bi12O17Br2/Bi4O5Br2, pH = 10) heterojunction with hierarchical heterostructure presented excellent photocatalytic activity under visible light for antibiotic tetracycline (TC), malachite green (MG) and methyl violet (MV) removal and the photodegradation efficiency could reach 97.3%, 90.4% and 87.5%, respectively. In addition, when CTAB was replaced by cetyltrimethylammonium chloride (CTAC), the as-obtained 2D flower-like type-I BCB-10.5 (BiOCl/Bi4O5Cl2, pH = 10.5) heterojunction also exhibited outstanding visible-light photocatalytic activity for the removal of TC, MG and MV. Greatly enhanced photocatalytic activity owed to synergistic effects including unique hierarchical morphology, large specific surface area and suitable band structures. According to the active species trapping experiments, feasible photocatalytic mechanisms were proposed.

Direct acidic graphene oxide enabled fabrication of three-dimensional molybdenum trisulfide and reduced graphene oxide nanohybrid aerogels with simultaneous energy storage and electrocatalytic capability

To confront the ever-growing energy and environmental concerns, the rational design and development of newer yet high-performance energy storage and conversion materials are highly desirable. Herein, we proposed a scalable and simplistic approach to prepare a three-dimensional (3D) MoS3/reduced graphene oxide (RGO) aerogel as an efficient electroactive material. Under a benign in-situ hydrothermal method, an acidic graphene oxide was directly used as support and catalyst to form uniformly dispersed MoS3 nanoparticles within porous 3D RGO architecture. Owing to its unique synergy of plentiful exposed active sites and highly porous conductive network, the resulting nanohybrid was successfully used as a supercapacitor electrode and electrocatalyst for hydrogen evolution reaction (HER). The as-obtained 3D MoS3/RGO nanohybrid-based electrode provides a higher specific capacitance of 576.5 F·g−1, more significant than the pristine MoS3 electrode (206.4 F g−1). Likewise, an asymmetric supercapacitor (ASC) device assembled using the MoS3/RGO and activated carbon (AC) delivers a maximum energy density of 35.2 Wh kg−1 at a power density of 528 W kg−1, over a voltage window of 1.5 V. Moreover, remarkable cycling stability accompanied by 92% capacitance retention was also observed. Similarly, the resulting 3D MoS3/RGO nanohybrids display significant HER activity, requiring a smaller overpotential of only 0.121 V to accomplish a current density of 10 mA·g−1 in conjunction with a smaller Tafel slope value of 60 mV dec−1 in 0.5 M H2SO4. Such remarkable electrocatalytic activity is accredited to its unique porous nanoarchitecture, sulfur-rich active centers, and improved conductivity. Overall, the implemented optimal methodology offers technological scalability in the fabrication of low-cost 3D nanohybrids electrodes composed of graphene and TMDs for various energy-related applications.

General Synthesis of Two-Dimensional Porous Metal Oxides/Hydroxides for Microwave Absorbing Applications.

Metal oxides/hydroxides with a two-dimensional (2D) porous structure have extensive applications in catalysis, microwave absorption, and energy storage fields due to their large specific surface areas, massive exposed active sites, and good structural integrities. Herein, a general surfactant-assisted vapor diffusion-deposition self-assembly method is developed to synthesize various 2D porous metal oxides/hydroxides. Benefiting from the structure-directing effect of surfactants and the precise tuning of nucleation and growth process that results from this vapor diffusion-deposition strategy, a 2D porous structure is constructed. To explore the advantages of such 2D porous structure, electromagnetic characteristics and absorbing properties of as-obtained materials are investigated. The minimum reflection loss (RL) of 2D porous NiFe2O4 is -23.1 dB at 6.4 GHz, and the effective absorption bandwidth (EAB) is 5.1 GHz. However, the minimum RL is only -15.0 dB at 8.7 GHz and the EAB is 3.9 GHz for NiFe2O4 particles. In addition, the as-obtained 2D porous NiFe2O4 exhibits superior absorbing properties compared with many previously reported nickel ferrites. Furthermore, the microwave absorbing mechanism of 2D porous NiFe2O4 is investigated.

High-Performance Solar Steam Generator Based on Polypyrrole-Coated Fabric via 3D Macro- and Microstructure Design.

Due to the abundance and easy availability of solar energy resources, solar-driven water evaporation provides a sustainable way to obtain clean water from wastewater and seawater. However, achieving a high evaporation rate with excellent light absorption remains a critical challenge in the structural regulation of evaporators. Herein, inspired by the natural transpiration process in plants (blue spruce), we designed a three-dimensional (3D) cone-shaped solar steam generator based on vertical polypyrrole nanowires-coated fabric (VPPyNWs-fabric). The microstructure design of polypyrrole (PPy) increases the solar energy absorption of the incident light through multiple reflections between the VPPyNWs, while the macrostructure design of the 3D evaporator possesses an enlarged surface area for energy harvesting, wide path for water supply, and open structure for vapor diffusion. As a proof of concept, the as-obtained 3D VPPyNWs-fabric-based solar steam generator demonstrates a fast water evaporation rate of 2.32 kg m-2 h-1 with high solar absorption of 97% and solar-to-vapor conversion efficiency of 98.56% at 1 kW m-2 energy density. In addition, the solar steam generator can be steadily applied in various water conditions, e.g., seawater, dye wastewater, and acidic and alkaline wastewater. This high-performance evaporator via 3D macro- and microstructure design offers a new avenue for better utilization of solar energy.

Three-dimensional reduced graphene oxide/cobaltosic oxide as a high-response sensor for triethylamine gas at room temperature

Three-dimensional (3D) reduced graphene oxide (rGO)/cobaltosic oxide (Co3O4) nanocomposites were prepared by a simple and low-cost hydrothermal method. Characterization results confirmed that rGO sheets were self-assembled to form a crosslinked porous network structure and Co3O4 nanoparticles were uniformly attached to the surface of rGO with the specific surface area of 306.49 m2/g. More importantly, the as-obtained 3D rGO/Co3O4 nanocomposites exhibited superior gas sensing property for ultra-low concentration detection of triethylamine (TEA) at room temperature; this was because of the mesoporous structure, large specific surface area, and excellent charge carrier transport properties of the nanocomposites. The response value of the 3D rGO/Co3O4 nanocomposite sensors to 1 ppm TEA gas was approximately 35% at room temperature, with extremely fast response and recovery time. 3D rGO/Co3O4 nanocomposites with excellent sensing performance have potential applications in the field of gas sensors.

Facile and Scalable Synthesis of 3D Structures of V10O24·12H2O Nanosheets Coated with Carbon toward Ultrafast and Ultrastable Zinc Storage

Three-dimensional (3D) structures of V10O24·12H2O nanosheets coated with carbon (denoted as V10O24@C) are facially and cost-effectively fabricated by reducing the V2O5-based aqueous solution with ethanol under hydrothermal conditions. By using the 3D V10O24@C as the cathode of zinc-ion batteries, the as-obtained 3D V10O24@C sample delivers excellent charge-discharge cycling capability, superior rate performance, and reasonable specific capacity, and a specific capacity of ca. 133.3 mA h g-1 and a 94.1% capacity retention are achieved even after 10000 cycles at a high current density of 10 A g-1 (∼80 C). Furthermore, it provides a facile and scalable approach to synthesize the 3D structures of pure-phased vanadium oxide nanosheets or other nanoscale metal oxides coated with carbon.

Rational design of bamboo mat-like 3D Ni foam@NiO@PPy nanoarray electrode for binder-free, high-loading and high-areal capacity lithium storage

Achieving high capacity and good cyclability of transition metal oxides anodes remains a challenge for lithium-ion batteries (LIBs) because of their poor conductivity and severe volume change. In this work, a bamboo mat-like nanoarray electrode consisting of NiO nanoarray interlayer and polypyrrole (PPy) coating layer growing directly on three-dimensional nickel foam (3D NF) conductive substrate (denoted as 3D NF@NiO@PPy) is reported to overcome the challenge. The 3D NF current collector can provide more active growth sites and thus achieve high loading (about 5.5 mg cm–2). The bamboo mat-like NiO nanoarray reduces the Li+ ions diffusion path and enhances the contact surface areas with the electrolyte, which can improve the electrochemical properties. The in-situ growth PPy coating can not only effectively suppress the volume expansion of NiO during the charge and discharge process, but also effectively improve the electrical conductivity of the electrode within a certain thickness range. Benefiting from this unique structure, the as-obtained 3D NF@NiO@PPy binder-free nanoarray electrode exhibits stable cycle performance and high reversible areal capacity of 4.90 mA h cm-2 at 0.5 mA cm-2. Remarkably, a large reversible capacity of 1.10 mA h cm-2 is also achieved even after 200 cycles at a relatively high current density of 2.5 mA cm-2. This work proposes a feasible strategy to enhance the capacity and stability of NiO anode and provides a new way for the practical application of self-supporting electrodes.

GEA Group, Germany

Three-dimensional (3D) reduced graphene oxide (rGO)/cobaltosic oxide (Co3O4) nanocomposites were prepared by a simple and low-cost hydrothermal method. Characterization results confirmed that rGO sheets were self-assembled to form a crosslinked porous network structure and Co3O4 nanoparticles were uniformly attached to the surface of rGO with the specific surface area of 306.49 m2/g. More importantly, the as-obtained 3D rGO/Co3O4 nanocomposites exhibited superior gas sensing property for ultra-low concentration detection of triethylamine (TEA) at room temperature; this was because of the mesoporous structure, large specific surface area, and excellent charge carrier transport properties of the nanocomposites. The response value of the 3D rGO/Co3O4 nanocomposite sensors to 1 ppm TEA gas was approximately 35% at room temperature, with extremely fast response and recovery time. 3D rGO/Co3O4 nanocomposites with excellent sensing performance have potential applications in the field of gas sensors.

People & Appointments

Three-dimensional (3D) reduced graphene oxide (rGO)/cobaltosic oxide (Co3O4) nanocomposites were prepared by a simple and low-cost hydrothermal method. Characterization results confirmed that rGO sheets were self-assembled to form a crosslinked porous network structure and Co3O4 nanoparticles were uniformly attached to the surface of rGO with the specific surface area of 306.49 m2/g. More importantly, the as-obtained 3D rGO/Co3O4 nanocomposites exhibited superior gas sensing property for ultra-low concentration detection of triethylamine (TEA) at room temperature; this was because of the mesoporous structure, large specific surface area, and excellent charge carrier transport properties of the nanocomposites. The response value of the 3D rGO/Co3O4 nanocomposite sensors to 1 ppm TEA gas was approximately 35% at room temperature, with extremely fast response and recovery time. 3D rGO/Co3O4 nanocomposites with excellent sensing performance have potential applications in the field of gas sensors.

Parker Hannifin Corp, USA

Three-dimensional (3D) reduced graphene oxide (rGO)/cobaltosic oxide (Co3O4) nanocomposites were prepared by a simple and low-cost hydrothermal method. Characterization results confirmed that rGO sheets were self-assembled to form a crosslinked porous network structure and Co3O4 nanoparticles were uniformly attached to the surface of rGO with the specific surface area of 306.49 m2/g. More importantly, the as-obtained 3D rGO/Co3O4 nanocomposites exhibited superior gas sensing property for ultra-low concentration detection of triethylamine (TEA) at room temperature; this was because of the mesoporous structure, large specific surface area, and excellent charge carrier transport properties of the nanocomposites. The response value of the 3D rGO/Co3O4 nanocomposite sensors to 1 ppm TEA gas was approximately 35% at room temperature, with extremely fast response and recovery time. 3D rGO/Co3O4 nanocomposites with excellent sensing performance have potential applications in the field of gas sensors.

Enhanced mass transfer in three-dimensional single-atom nickel catalyst with open-pore structure for highly efficient CO2 electrolysis

Design of efficient catalysts for electrochemical reduction of carbon dioxide (CO2) with high selectivity and activity is of great challenge, but significant for managing the global carbon balance. Herein, a series of three-dimensional (3D) single-atom metals anchored on graphene networks (3D SAM-G) with open-pore structure were successfully mass-produced via a facile in-situ calcination technique assisted by NaCl template. As-obtained 3D SANi-G electrode delivers excellent CO Faradaic efficiency (FE) of >96% in the potential range of −0.6 to −0.9 V versus reversible hydrogen electrode (RHE) and a high current density of 66.27 mA cm−2 at −1.0 V versus RHE, outperforming most of the previously reported catalysts tested in H-type cells. Simulations indicate that enhanced mass transport within the 3D open-pore structure effectively increases the catalytically active sites, which in turn leads to simultaneous enhancement on selectivity and activity of 3D SANi-G toward CO2 electroreduction. The cost-effective synthesis approach together with the microstructure design concept inspires new insights for the development of efficient electrocatalysts.

Direct growth of Fe-incorporated NiSe microspheres on FeNi alloy foam as a highly efficient electrocatalyst for oxygen evolution reaction

Transition metal selenides with special structures and rational component modulation have received tremendous research interest to ameliorate the sluggish kinetics of oxygen evolution reaction (OER) in electrochemical water splitting. Here, we propose a facile hydrothermal treatment strategy to prepare porous Fe-incorporated NiSe microspheres via in situ selenization of iron–nickel foam. The as-obtained 3D integrated anode demonstrates excellent electrocatalytic performance towards OER in concentrated alkaline media (1.0 M KOH), with a small onset overpotential of 170 mV, an overpotential as low as 236 mV to achieve a current density of 50 mA cm−2, and a small Tafel slope of 53 mV dec−1. The overpotential at 50 mA cm−2 shows no obvious change during the whole durability test for 24 h, indicating long-term stable electrocatalytic activity. Characterizations of the electrode after stability test reveal the oxidation of the crystallized Fe-incorporated NiSe microspheres which probably generates amorphous Ni(Fe)OOH. The microspheres were partially dissolved and connected with each other to form a wormlike porous structure. The superior OER activity is largely attributed to the highly active Fe–Ni selenide and derived oxyhydroxide of 3D porous structure on the FeNi foam substrate. The facile synthesis strategy in this work can be conveniently applied to the preparation of a variety of selenides of metal foams with different compositions as highly efficient electrocatalysts.