3D Porous Architecture Research Articles

Three-Dimensional Heteroatom-Doped Nanocarbon for Metal-Free Oxygen Reduction Electrocatalysis: A Review

The oxygen reduction reaction (ORR) at the cathode is a fundamental process and functions a pivotal role in fuel cells and metal–air batteries. However, the electrochemical performance of these technologies has been still challenged by the high cost, scarcity, and insufficient durability of the traditional Pt-based ORR electrocatalysts. Heteroatom-doped nanocarbon electrocatalysts with competitive activity, enhanced durability, and acceptable cost, have recently attracted increasing interest and hold great promise as substitute for precious-metal catalysts (e.g., Pt and Pt-based materials). More importantly, three-dimensional (3D) porous architecture appears to be necessary for achieving high catalytic ORR activity by providing high specific surface areas with more exposed active sites and large pore volumes for efficient mass transport of reactants to the electrocatalysts. In this review, recent progress on the design, fabrication, and performance of 3D heteroatom-doped nanocarbon catalysts is summarized, aiming to elucidate the effects of heteroatom doping and 3D structure on the ORR performance of nanocarbon catalysts, thus promoting the design of highly active nanocarbon-based ORR electrocatalysts.

Self-Referenced Smartphone Imaging for Visual Screening of H2S Using Cu xO-Polypyrrole Conductive Aerogel Doped with Graphene Oxide Framework.

Cu xO-polypyrrole conductive aerogel loaded on graphene oxide framework (Cu xO-PPy@GO) with a three-dimensional (3D) porous architecture was utilized for high-efficient visual screening of H2S on a flexible paper substrate. The detectable signal was acquired on a portable smartphone by using a self-referenced imaging platform equipped with the light emitting diode (LED) accompanying an image processing. As a proof-of-concept, Cu xO-PPy@GO aerogel-based sensing strategy was also developed for Na2S detection and egg spoilage monitoring. Such a flexible paper-supported sensor is expected for potential application in portable and wearable food-safety fields.

Facile synthesis of three dimensional porous cellular carbon as sulfur host for enhanced performance lithium sulfur batteries

Lithium sulfur battery has drawn intense interests due to its high theoretical specific capacity and high energy density. However, it remains a big challenge to achieve high capacities and sulfur loadings of cathode via a facile and scaled-up method for the practical applications of lithium sulfur batteries. Herein we designed a three dimensional porous cellular carbon framework (PCCF) as sulfur host via a simple template-activation method. The honeycomb architecture of the PCCF with high BET surface area could encapsulate high content sulfur and the 3D interconnected carbon framework could realize high sulfur loading electrode. Benefiting from the 3D porous cellular architecture, the obtained cellular PCCF/S cathode delivers a notable enhancement in the sulfur content, sulfur loading, cycling stability and rate performance. The PCCF/S cathode with high sulfur content of 84.75% exhibits an initial discharge capacity of 1264.4 mAh g−1 at 0.1C rate and shows good cycling stability with a low capacity decay rate of 0.14% per cycle after 200 cycles at 1C rate. With a high sulfur loading of 6.40 mg cm−2, the cell delivers an initial discharge capacity of 1162.3 mAh g−1 and maintains good cycling stability.

Powering the Internet of Things

Internet connected devices are limited by the performance of microbatteries that power them. In this issue of Joule, Hur et al. develop microbatteries with tall 3D electrodes that have high areal energy densities. These microbatteries were fabricated on a silicon wafer using silicon and polymer processing that are compatible with microelectronics, paving the way for future microbattery and microelectronics integration.

Template-Oriented Synthesis of Nitrogen-Enriched Porous Carbon Nanowhisker by Hollow TiO2 Spheres Nanothorns for Methanol Electrooxidation

Boosting the electrocatalytic property of catalyst by controlling the structure and composition is extremely important for fuel cells commercialization. We present herein a facile template-oriented strategy to controllably fabricate one-dimensional (1D) nitrogen-enriched hierarchical porous carbon nanowhisker (N-HPCN-T, T = 700, 800, and 900) through an efficient hollow TiO2 (H-TiO2) spheres nanothorns (H-TiO2/N-HPCN-T). This strategy not only effectively provides an interconnected 3D porous architecture (hollow micro/dual-meso-porous and 1D nanowhisker) but also significantly improves the specific surface area and electrical conductivity of TiO2 materials. The growth mechanism of polyaniline nanowhisker and the effect of experimental parameters have been systematically studied, and then a “template-oriented mechanism” for the nanowhisker growth is proposed. Pt nanoparticles are deposited on H-TiO2/N-HPCN-T supports using a microwave-assisted polyol process (Pt/H-TiO2@N-HPCN-T). Because of their unique st...

Three-dimensional graphene as gas diffusion layer for micro direct methanol fuel cell

The gas diffusion layer (GDL), as an important structure of the membrane electrode assembly (MEA) of the direct methanol fuel cell (DMFC), provides a support layer for the catalyst and the fuel and the product channel. Traditionally, the material of GDL is generally carbon paper (CP). In this paper, a new material, namely three-dimensional graphene (3DG) is used as GDL for micro DMFC. The experimental results reveal that the performance of the DMFC has been improved significantly by application of 3DG. The peak powers increase from 25 mW to 31.2 mW and 32 mW by using 3DG as the anode and cathode GDL instead of CP, respectively. The reason may be the decrease of charge and mass transfer resistance of the cell. This means that the unique 3D porous architecture of the 3DG can provide lower contact resistance and sufficient fuel diffusion paths. The output performance of the cell will be further improved when porous metal current collectors is used.

Porous Co3O4 decorated nitrogen-doped graphene electrocatalysts for efficient bioelectricity generation in MFCs

High-performance, low-cost, and robust oxygen reduction reaction (ORR) catalysts have played a very crucial role in the development of microbial fuel cells (MFCs). Herein, A novel in-situ Co3O4 nanoparticles (NPs) modified nitrogen-doped graphene with three-dimensional porous structure (3D GN-Co3O4) has been successfully synthesized and employed as an efficient ORR catalyst in MFCs. Benefiting from 3D porous architecture feature, highly intrinsic conductivity and synergistic effect between nitrogen-doped graphene and Co3O4 NPs, the 3D GN-Co3O4 as a cathode catalyst in alkaline condition realizes significantly enhanced electrochemical performance and outstanding cycling stability. Furthermore, the self-assembly of MFCs based on the 3D GN-Co3O4 cathode offers a high power density of 578 ± 10 mW m−2, which is even comparable to the commercial Pt/C.

Electrochemical mineralization of sulfamethoxazole over wide pH range using FeIIFeIII LDH modified carbon felt cathode: Degradation pathway, toxicity and reusability of the modified cathode

Hierarchical three-dimensional (3D) porous architecture FeIIFeIII layered double hydroxide (LDH) multiwall was grown on carbon-felt (CF) substrate via solvothermal process. The as-deposited FeIIFeIII LDH/CF cathode was composed of highly oriented and well crystallized interconnected nanowalls with high electrical conductivity and excellent catalytic activity over a wide pH range (pH 3–9) for heterogeneous electro-Fenton (HEF) degradation of antibiotic sulfamethoxazole (SMT) in aqueous medium. Mineralization efficiencies (in terms of TOC removal) of ∼97%, 93% and 90% was achieved at pH 3, 6 and 9 respectively for FeIIFeIII cathode during HEF treatment of 0.2 mM SMT solution at applied current density of 7.5 mA cm−2 using Ti4O7 anode. Comparative electro-Fenton (EF-Fe2+) with 0.2 mM Fe2+ or electrooxidation with H2O2 production (EO-H2O2) studies using raw CF cathode at similar experimental conditions showed relatively lower mineralization with highest TOC removal efficiency of 77% and 64% obtained at pH 3 for EF-Fe2+ and EO-H2O2 respectively. Oxidative degradation of SMT in HEF system was by (i) Ti4O7(OH) generated at anode surface at all pH studied, (ii) surface catalyzed process and (iii) contribution from homogeneous catalyzed process at pH 3 due to leached iron ions. The prepared FeIIFeIII LDH/CF exhibited excellent catalytic stability with good reusability up to 10 cycles of 4 h treatment at pH 6. Initial SMT solution showed relatively high toxicity but total detoxification of the solution was attained after 8 h of treatment by HEF with FeIIFeIIILDH/CF cathode. HEF with FeIIFeIII LDH/CF cathode is an exciting technique for remediation of organic contaminated wastewater.

Defective N/S-Codoped 3D Cheese-Like Porous Carbon Nanomaterial toward Efficient Oxygen Reduction and Zn-Air Batteries.

Developing a facile and cost-efficient method to synthesize carbon-based nanomaterials possessing excellent structural and functional properties has become one of the most attractive topics in energy conversion and storage fields. In this study, density functional theory calculation results reveal the origin of high oxygen reduction reaction (ORR) activity predominantly derived from the synergistic effect of intrinsic defects and heteroatom dopants (e.g., N, S) that modulate the bandgap and charge density distribution of carbon matrix. Under the guidance of the first-principle prediction, by using ultralight biomass waste as precursor of C, N, and S elements, a defect-rich and N/S dual-doped cheese-like porous carbon nanomaterial is successfully designed and constructed. Herein, the intrinsic defects are artfully generated in terms of alkaline and ammonia activation. The electrochemical measurements display that such a material owns a comparable ORR activity (E1/2 = 0.835 V) to the commercial Pt/C catalyst, along with splendid durability and methanol tolerance in alkali media. Furthermore, as cathode catalyst, it displays a high Zn-air battery performance. The excellent ORR activity of the catalyst can be attributed to its unique 3D porous architecture, abundant intrinsic defects, and high-content active heteroatom dopants in the carbon matrix.

Superhydrophobic, ultralight and flexible biomass carbon aerogels derived from sisal fibers for highly efficient oil–water separation

With the massive discharge of industrial oily wastewater and the frequent occurrence of oil spills at sea in recent years, the fabrication of superhydrophobic and durable oil-absorbing materials is urgently required for oil recovery and disposal of oily water in practical applications. In this paper, ultralight, elastic, superhydrophobic and durable carbon fiber aerogels (CFAs) derived from sisal leaves were prepared via simple alkalization, bleaching, freeze-drying and carbonization. The prepared CFAs were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption–desorption, contact angle measurement and scanning electron microscopy. The as-prepared CFAs with 3D porous architectures and excellent flexibility under compression were found to be effective oil absorption material for various oils and organic solvents. Textural analyses showed that the CFAs consist of fiber morphologies with high porosity originating from vacancies between individual fibers. The nitrogen sorption analysis confirmed that the material is mesoporous with average pore diameter of 3.03 nm and Brunauer–Emmett–Teller surface area of 399.85 m2/g. The contact angle measurements revealed that CFAs show both superoleophilic and superhydrophobic properties simultaneously with an oil contact angle of 0° and a static water contact angle of 153 ± 1°, thus the aerogels possessed a good oil–water separation ability. Furthermore, the CFAs exhibited a superior absorption capacity in the range from 90 to 188 times of their own weight for different organic solvents and oils. After recycling 10 times, the CFAs still exhibit excellent oils absorption properties, as well as exhibit excellent stability under harsh conditions, showing that the CFAs has excellent reusability performance. This work provides a green strategy to utilize low-cost biomass as raw materials to fabricate superhydrophobic CFAs as an oil absorbent, which has great potential in application of disposal of oily water and environmental protection.

Fabrication of BiOI/graphene Hydrogel/FTO photoelectrode with 3D porous architecture for the enhanced photoelectrocatalytic performance

Three-dimensional (3D) porous networkstructural BiOI-graphene hydrogel-FTO (BiOI/GH/FTO) electrode with remarkably superior photoelectrocatalytic degradation activity and photoelectrocatalytic mineralization ability was successfully prepared by a two-step electrodeposition method. The BiOI nanosheets were electrodeposited into the architectures of 3D porous graphene hydrogel which was prepared by the electrochemical reduction of GO in aqueous dispersion. The morphology and amount of BiOI can be controlled by the electrochemical deposition. With the deposition time of BiOI for 60 s and the working voltage at 1.0 V, the photoelectrocatalytic activity of the 3D BiOI/GH/FTO achieved to the maximum. The removal rate of phenol can be up to about 83% in 5 h, which was 13.8 times higher than that of BiOI/FTO electrode. The degradation rate and mineralization rate of phenol in the solution absence of Na2SO4 electrolyte were 76.8% and 56.8%, respectively, which were 13.2 times and 33.4 times as high as that of the BiOI/FTO. The enhanced photoelectrocatalytic degradation activity of 3D BiOI/GH/FTO is due to the 3D porous architecture and a larger surface area of graphene hydrogel which is favorable for reactant diffusion, and the superior electrical conductivity which promotes the charges to transfer excited by BiOI. The BiOI/GH/FTO electrode has the excellent stability. The degradation rates of phenol nearly unchanged after 4 cyclic degradations in static system and a long-term degradation for 72 h in dynamical system. Trapping experiment shows that the hole might be the main active species in photoelectrocatalytic degradation. This research provides new insights in the development of a new photoelectrocatalytic material for the removal of organic compound.

Multiporous molybdenum carbide nanosphere as a new charming electrode material for highly sensitive simultaneous detection of guanine and adenine

By introduction of Mo metal species (molybdenum-based polyoxometalates) into the Cu-MOF as co-precursor, molybdenum carbide nanosphere (MoxC@C) was prepared via a simple calcining routine and a further etching the metallic Cu process. The obtained MoxC@C showed a unique structure where well-dispersed MoxC nanoparticles (NPs) were encapsulated in porous carbon matrix. As-fabricated novel 3D porous architecture MoxC@C nanosphere exhibited a potent and persistent electro-oxidation behavior followed by well-separated oxidation peaks (peak to peak voltage is about 350 mV) toward adenine (A) and guanine (G) by differential pulse voltammetry (DPV). This excellent electrochemical performance can be attributed to the unique structure and composition of 3D MoxC@C. Furthermore, 3D MoxC@C also revealed high selectivity and sensitivity, good reproducibility, excellent stability and anti-interference ability. The calibration curves for quantitive analysis of G and A were obtained: 0.03–122 µM, and 0.02–122 µM, respectively, the detection limits were 0.0085 µM, 0.008 µM, respectively. The proposed procedure was successfully applied to detect G and A in human urine and serum samples with satisfactory recovery, which manifests its viability application for practical analysis.

Co Nanoparticles Confined in 3D Nitrogen-Doped Porous Carbon Foams as Bifunctional Electrocatalysts for Long-Life Rechargeable Zn-Air Batteries.

Proper design and simple preparation of nonnoble bifunctional electrocatalysts with high cost performance and strong durability for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) is highly demanded but still full of enormous challenges. In this work, a spontaneous gas-foaming strategy is presented to synthesize cobalt nanoparticles confined in 3D nitrogen-doped porous carbon foams (CoNCF) by simply carbonizing the mixture of citric acid, NH4 Cl, and Co(NO3 )2 ·6H2 O. Thanks to its particular 3D porous foam architecture, ultrahigh specific surface area (1641 m2 g-1 ), and homogeneous distribution of active sites (C-N, Co-Nx , and Co-O moieties), the optimized CoNCF-1000-80 (carbonized at 1000 °C, containing 80 mg Co(NO3 )2 ·6H2 O in precursors) catalyst exhibits a remarkable bifunctional activity and long-term durability toward both ORR and OER. Its bifunctional activity parameter (ΔE) is as low as 0.84 V, which is much smaller than that of noble metal catalyst and comparable to state-of-the-art bifunctional catalysts. When worked as an air electrode catalyst in rechargeable Zn-air batteries, a high energy density (797 Wh kg-1 ), a low charge/discharge voltage gap (0.75 V), and a long-term cycle stability (over 166 h) are achieved at 10 mA cm-2 .

Design and fabrication of a non-clogging scaffold composed of semi-permeable membrane

In this study, a novel concept of polymer scaffold was proposed based on 3D porous membrane architecture. It had two distinct sub-volumes intertwined with each other but separated by a single continuous smooth semi-permeable membrane. One sub-volume was used for cell culture, while the other served as a perfusion channel. Mass transfer was implemented through the interfacial porous membrane. Consequently, this scaffold was expected to be completely free from clogging problem due to growing tissue. The sample scaffolds of poly l-lactic acid (PLLA) was fabricated based on 3D UV photo-lithography and porogen leaching technique, which provided a P-surface-like architecture composed of porous membrane having smooth and fine texture with considerably high porosity. Despite high overall porosity of approximately 97%, these scaffolds had strengths and Young's moduli appropriate for regeneration of bones or cartilages. Wettability and permeability of polydopamine-coated PLLA porous membrane were sufficiently high.

A 3D architecture composite of porous vanadium nitride nanoribbons and reduced graphene oxide as a high-efficiency counter electrode for dye-sensitized solar cells.

A three-dimensional (3D) porous architecture combining porous vanadium nitride nanoribbons with reduced graphene oxide was prepared through a hydrothermal process and subsequent thermal annealing in an ammonia/argon mixed atmosphere. Then, the obtained 3D porous vanadium nitride nanoribbon/reduced graphene oxide (PVNN/RGO) composite was explored as the counter electrode of dye-sensitized solar cells (DSCs). As evidenced by the electrochemical measurements, the 3D PVNN/RGO composite demonstrates excellent electrocatalytic performance, which is comparable to that of Pt. This can be attributed to the fact that the 3D architecture composite of porous vanadium nitride and reduced graphene oxide can simultaneously provide a favorable electrolyte diffusion channel, a fast electron-transport network, and an abundance of efficient electrocatalytic active sites. By employing such PVNN/RGO composite as the counter electrode, the fabricated DSC can achieve a conversion efficiency of 7.43%, which is comparable to that of the conventional Pt counter electrode (7.74%). Therefore, the 3D PVNN/RGO composite is a promising low-cost alternative to the expensive Pt as a counter electrode in DSCs.

Self-assembly of 3D porous architectures from energetic nanoparticles for enhanced energetic performances

3D architectures with porous network of energetic molecules were designed and constructed by introduce a general approach through two-step self-assembly process.

Flexible WS2@CNFs Membrane Electrode with Outstanding Lithium Storage Performance Derived from Capacitive Behavior

AbstractFlexible electrodes have recently elicited attention due to their potential to be woven into textiles as flexible power supplies for wearable electronic devices. However, contemporary flexible electrodes generally suffer from the limited reaction kinetics and inferior stability. Here, a flexible WS2@CNFs membrane electrode is facilely fabricated via hydrothermal method and subsequent electrospinning to embed WS2 nanosheets into interconnected framework of carbon nanofibers (CNFs). Benefitting from 3D porous architecture and good conductivity of CNFs, WS2@CNFs composites exhibit outstanding cycling stability and rate capability as self‐supported binder‐free anode for lithium‐ion batteries. Especially, WS2@CNFs with 60.3 wt% of WS2 displays a discharge specific capacity as high as 545 mA h g−1 at 0.5 A g−1 after 800 cycles. Even at 2 A g−1, it maintains 62.4% of specific capacity at 0.1 A g−1, and stably cycles back at 0.1 A g−1. Kinetic analysis confirms that the capacitive mechanism is dominant in the Li‐ion storage process, which is derived mainly from the structure evolution from WS2 nanosheets to WS2/W nanoparticles during extended cycling. The reduced nanoparticles also enhance electrochemical activity, conductivity, and reversibility of the conversion reaction, resulting in the increasing capacity with cycles.

Hydrothermal growth of 3D graphene on nickel foam as a substrate of nickel-cobalt-sulfur for high-performance supercapacitors

A facile and efficient one-step hydrothermal approach is presented to prepare a three-dimensional graphene-nanosheets/nickel foam (3D NF/G) substrate for pseudocapacitive materials to utilize its high specific surface area and short ion channel lengths. Scanning electron microscope (SEM) observation shows thin graphene nanosheets (∼10 nm) are assembled into 3D porous architectures and uniformly deposited on NF for the NF/G substrate obtained under addition of KOH at low graphene oxide (GO) concentration. Raman and X-ray photoelectron spectroscopy (XPS) analysis further shows the homogenous dispersion of GO in the solution increases reducibility of graphene and avoids agglomeration of nanosheets during the hydrothermal process, which accelerate the graphene nanosheets self-assemble into 3D interconnected structures on NF. Furthermore, flower-like Ni-Co-S nanosheets was then deposited on NF/G substrate by electrodeposition to form NF/G/Ni-Co-S composite, in which 3D graphene can guarantee the high utilization of electroactive species and favorable reaction kinetics. The as-synthesized electrode shows greatly improved electrochemical performances with an ultrahigh specific capacitance of 2526 F g−1 at a current density of 2 A g−1 and of 1916 F g−1 even at a current density of 10 A g−1. Additionally, it also exhibits superior cycle stability by retaining 77.0% of its original state after 2000 cycles at high current density of 20 A g−1, indicating promising applications as an efficient electrode for supercapacitors.

Ni2 P@Carbon Core-Shell Nanoparticle-Arched 3D Interconnected Graphene Aerogel Architectures as Anodes for High-Performance Sodium-Ion Batteries.

To alleviate large volume change and improve poor electrochemical reaction kinetics of metal phosphide anode for sodium-ion batteries, for the first time, an unique Ni2 P@carbon/graphene aerogel (GA) 3D interconnected porous architecture is synthesized through a solvothermal reaction and in situ phosphorization process, where core-shell Ni2 P@C nanoparticles are homogenously embedded in GA nanosheets. The synergistic effect between components endows Ni2 P@C/GA electrode with high structural stability and electrochemical activity, leading to excellent electrochemical performance, retaining a specific capacity of 124.5 mA h g-1 at a current density of 1 A g-1 over 2000 cycles. The robust 3D GA matrix with abundant open pores and large surface area can provide unblocked channels for electrolyte storage and Na+ transfer and make fully close contact between the electrode and electrolyte. The carbon layers and 3D GA together build a 3D conductive matrix, which not only tolerates the volume expansion as well as prevents the aggregation and pulverization of Ni2 P nanoparticles during Na+ insertion/extraction processes, but also provides a 3D conductive highway for rapid charge transfer processes. The present strategy for phosphides via in situ phosphization route and coupling phosphides with 3D GA can be extended to other novel electrodes for high-performance energy storage devices.

Plasmonic Wood for High‐Efficiency Solar Steam Generation

AbstractPlasmonic metal nanoparticles are a category of plasmonic materials that can efficiently convert light into heat under illumination, which can be applied in the field of solar steam generation. Here, this study designs a novel type of plasmonic material, which is made by uniformly decorating fine metal nanoparticles into the 3D mesoporous matrix of natural wood (plasmonic wood). The plasmonic wood exhibits high light absorption ability (≈99%) over a broad wavelength range from 200 to 2500 nm due to the plasmonic effect of metal nanoparticles and the waveguide effect of microchannels in the wood matrix. The 3D mesoporous wood with numerous low‐tortuosity microchannels and nanochannels can transport water up from the bottom of the device effectively due to the capillary effect. As a result, the 3D aligned porous architecture can achieve a high solar conversion efficiency of 85% under ten‐sun illumination (10 kW m−2). The plasmonic wood also exhibits superior stability for solar steam generation, without any degradation after being evaluated for 144 h. Its high conversion efficiency and excellent cycling stability demonstrate the potential of newly developed plasmonic wood to solar energy‐based water desalination.