Ultra-large Surface Area Research Articles

Voltage regulation toward stable cycling of sodium vanadium oxy-fluorophosphates for high-performing, mechanically robust aqueous sodium-ion hybrid capacitors

Sodium vanadium oxy-fluorophosphates (Na3V2O2x(PO4)2F3−2x, NVOPF, 0 ≤ x ≤ 1) are promising cathodes for aqueous sodium-ion hybrid capacitors (ASIHCs) due to their high theoretical capacity and operation potential. However, the extremely poor cycle life and unclear failure mechanism greatly hinder their application in ASIHCs. Here, the intrinsic capacity degradation mechanism of NVOPF is elucidated and a unique voltage regulation strategy is proposed. By slightly compressing the charge cut-off voltage to 1.0 V (vs. SCE, saturated calomel electrode), the vanadium dissolution of NVOPF nanocomposite is significantly suppressed and superior cycling stability is achieved (79.67 % after 800 cycles), among the best reported for NVOPF operating in aqueous electrolytes. Microporous zeolite-templated carbon (ZTC) with ultra-large surface area is selected as a unique capacitive anode for pairing and intentionally activated via an electrochemical oxidation, providing huge pseudocapacitance that is ∼23 times higher than pristine ZTC. Furthermore, a high-performing 2.1 V quasi-solid-state NVOPF-based ASIHC is developed by designing an electrode-compatible polyacrylamide (PAM)-17 m (mol kg−1) NaClO4 hydrogel electrolyte with high ionic conductivity and adhesiveness, which not only provides recordable cycle stability, superior rate performance and high energy/power density, but also demonstrates exceptional safety, flexibility, and robust durability against extreme conditions, including short circuit, nail penetration and mechanical damage.

Evaluation of adsorption performance and mechanisms of a highly effective 3D boron-doped graphene composite for amitriptyline pharmaceutical removal

Three-dimensional heteroatom-doped graphene presents a state-of-the-art approach for effective remediation of pharmaceutical wastewater on account of its distinguished adsorption and physicochemical attributes. Amitriptyline is an emerging tricyclic antidepressant pollutant posing severe risks to living habitats through water supply and food chain. With ultra-large surface area and plentiful chemical functional groups, graphene oxide is a favorable adsorbent for decontaminating polluted water. Herein, a new boron-doped graphene oxide composite reinforced with carboxymethyl cellulose was successfully developed via solution-based synthesis. Characterization study revealed that the adsorbent was formed by graphene sheets intertwined into a porous network and engrafted with 13.37 at% of boron. The adsorbent has a zero charge at pH 6 and contained various chemical functional groups favoring the attachment of amitriptyline. It was also found that a mere 10 mg of adsorbent was able to achieve relatively high amitriptyline removal (89.31%) at 50 ppm solution concentration and 30 °C. The amitriptyline adsorption attained equilibrium within 60 min across solution concentrations ranging from 10 to 300 ppm. The kinetic and equilibrium of amitriptyline adsorption were well correlated to the pseudo-second-order and Langmuir models, respectively, portraying the highest Langmuir adsorption capacity of 737.4 mg/g. Notably, the predominant mechanism was chemisorption assisted by physisorption that contributed to the outstanding removal of amitriptyline. The saturated adsorbent was sufficiently regenerated using ethanol eluent. The results highlighted the impressive performance of the as-synthesized boron-doped adsorbent in treating amitriptyline-containing waste effluent.

Wafer-Level, High-Performance, Flexible Sensors Based on Organic Nanoforests for Human-Machine Interactions.

High-performance flexible sensors are essential for real-time information analysis and constructing noncontact communication modules for emerging human-machine interactions. In these applications, batch fabrication of sensors that exhibit high performance at the wafer level is in high demand. Here, we present organic nanoforest-based humidity sensor (NFHS) arrays on a 6 in. flexible substrate prepared via a facile, cost-effective manufacturing approach. Such an NFHS achieves state-of-the-art overall performance: high sensitivity and fast recovery time; the best properties are at a small device footprint. The high sensitivity (8.84 pF/% RH) and fast response time (5 s) of the as-fabricated organic nanoforests are attributed to the abundant hydrophilic groups, the ultra-large surface area with a huge number of nanopores, and the vertically distributed structures beneficial to the transfer of molecules up and down. The NFHS also exhibits excellent long-term stability (90 days), superior mechanical flexibility, and good performance repeatability after bending. With these superiorities, the NFHS is further applied as a smart noncontact switch, and the NFHS array is used as the motion trajectory tracker. The wafer-level batch fabrication capability of our NFHS provides a potential strategy for developing practical applications of such humidity sensors.

Enhanced adsorption capacity of tetracycline on porous graphitic biochar with an ultra-large surface area.

Excessive tetracycline in the water environment may lead to the harming of human and ecosystem health. Removing tetracycline antibiotics from aqueous solution is currently a most urgent issue. Porous graphitic biochar with an ultra-large surface area was successfully prepared by a one-step method. The effects of activation temperature, activation time, and activator dosage on the structural changes of biochar were investigated by scanning electron microscopy, Brunauer-Emmett-Teller, X-ray powder diffraction, and Raman spectroscopy. The effect of the structure change, adsorption time, temperature, initial pH, and co-existing ions on the tetracycline removal efficiency was also investigated. The results show that temperature had the most potent effect on the specific surface area, pore structure, and extent of graphitization. The ultra-large surface area and pore structure of biochar are critical to the removal of tetracycline. The q e of porous graphitic biochar could reach 1122.2 mg g-1 at room temperature. The calculations of density functional theory indicate that π-π stacking interaction and p-π stacking interaction can enhance the tetracycline adsorption on the ultra-large surface area of graphitic biochar.

Emerging 2D pnictogens: a novel multifunctional photonic nanoplatform for cutting-edge precision treatment.

The elements of the pnictogen group, known as the 15th (VA) family in the periodic table, including phosphorus (P), arsenic (As), antimony (Sb) and bismuth (Bi), have been widely used by alchemists to treat various diseases since ancient times and hold a pivotal position in the history of medicine, owing to their diverse pharmacological activities. Recently, with the development of modern nanotechnology, pnictogen group elements appear in a more innovative form, namely two-dimensional (2D) pnictogens (i.e. phosphorene, arsenene, and bismuthene) with a unique layered crystal structure and extraordinary optoelectronic characteristics, which endow them with significant superiority as a novel multifunctional photonic nanoplatform for cutting-edge precision treatment of various diseases. The puckered layer structure with ultralarge surface area make them ideal drug and gene delivery vectors that can avoid degradation and reduce target effects. The anisotropic morphology allows their easier internalization by cells and may improve gene transfection efficiency. Tunable optoelectronic characteristics endow them with excellent phototherapy performance as well as the ability to act as an optical switch to initiate subsequent therapeutic events. This review provides a brief overview of the properties, preparation and surface modifications of 2D pnictogens, and then focuses on its applications in cutting-edge precision treatment as a novel multifunctional photonic nanoplatform, such as phototherapy, photonic medicine, photo-adjuvant immunotherapy and photo-assisted gene therapy. Finally, the challenges and future development trends for 2D pnictogens are provided. With a focus on 2D pnictogen-based multifunctional photonic nanoplatforms, this review may also provide profound insights for the next generation innovative precision therapy.

Zero-Carbon Emission Chemical Method to Remove Formaldehyde without Catalyst by Highly Porous Polymer Composites at Room Temperature.

Herein, the fabrication of reduced graphene oxide (RGO)-templated polymer composites for chemical removal of gaseous formaldehyde under ambient conditions is presented. The chemical removal of formaldehyde is achieved by a nucleophilic addition reaction between formaldehyde and aminooxy groups on the polymer chain ends to form the oxime bonds with the only byproduct of H2 O. RGO is essential since it not only has an ultralarge surface area but also can act as a perfect template for immobilizing pyrene-terminated and aminooxy-functionalized polymers via strong π-π stacking interactions, while melamine foam provides a three-dimensional skeleton for loading RGO/polymer composites to afford a porous 3D structure for efficient formaldehyde removal. Since the oxime bond can be cleaved into aminooxy group in acidic media, the RGO/polymer composite can be regenerated for repeatable usage, which shows an excellent performance of adsorbing 14mg of formaldehyde by 100mg of the polymer at ambient condition.

Electrocatalytic Reduction of Carbon Dioxide to High-Value Multicarbon Products with Metal–Organic Frameworks and Their Derived Materials

The electrocatalytic carbon dioxide reduction reaction (CO2RR) holds great potential in promoting carbon neutral through effectively converting CO2 molecules to useful chemicals and fuels. The high-efficiency electrochemical conversion of CO2 to single-carbon products has been well realized, while more efforts are needed for the generation of high-value multicarbon products. Metal–organic frameworks (MOFs), featuring porous structures, high chemical tunability, and ultralarge surface area, have attracted increasing attention in the electrochemical CO2RR. Herein, we review the recent progress of electrocatalytic CO2RR on MOF-based materials toward multicarbon products. First, the structure of MOFs is briefly introduced. Then, the electrocatalytic CO2RR performance and the corresponding catalytic mechanism of pristine MOFs (classified according to the kind of organic ligands/linkers) and MOF-derived materials (including metal nanomaterials, single-atom catalysts and nanocomposites) toward the multicarbon product generation are systematically discussed. Finally, critical challenges and potential opportunities are highlighted to inspire the rational design and targeted synthesis of advanced MOF-based materials for high-performance electrocatalytic CO2 reduction toward multicarbon products.

Metal-organic-framework based catalyst for hydrogen production: Progress and perspectives

Fossil fuel shortage and global warming have inspired scientists to search for alternative energy sources which are green, renewable, and sustainable. Hydrogen formed from water splitting has been considered as one of the most promising candidates to replace traditional fuels due to its low production cost and zero-emission. Metal-organic frameworks (MOFs) have been considered as potential catalysts for hydrogen production from water splitting account for their flexible structure, ultra-large surface area, and chemical component diversification. This paper reviews different kinds of MOF-related electrocatalysts, involving metals, metal oxides, single atoms, metal phosphides, metal nitrides, and metal dichalcogenides for hydrogen production. Also, MOF-based photocatalysts consisting of pristine MOFs, MOFs as supporters, and MOF-derived heterojunction architectures are reviewed. The finding of MOF-based catalysts for hydrogen generation is summarized. The pros and cons of different MOF-based materials as catalysts for water splitting are discussed. Finally, current challenges and the potential developments of these unique materials as catalysts are also provided.

Ultraviolet-Induced Interfacial Crystallization of Uniform Nanoporous Biphasic TiO2 Spheres for Durable Lithium-Ion Battery

Porous TiO2 has been widely studied as an anode material of lithium-ion battery, most of which, however, are crystalline with a limited surface area (e.g., 50–120 m2/g) and a large pore size of 10–20 nm greatly exceeding the ion radium of Li+ ion and its complexes. Herein a facile UV-induced interfacial crystallization method is developed for the sol–gel-derived amorphous hydrous TiO2 spheres (HTS) at ambient condition. Tuning the dispersant (e.g., ethanol, H2O, methanol, or their mixture) and the wavelength of the light source allows for selective control over the crystal phase of anatase, rutile, or their biphase formed at the spherical surface, although the total crystallinity remains poor. The optimal nanoporous biphasic TiO2 spheres of anatase and rutile upon 254 nm UVC irradiation of HTS in H2O and methanol mixed solution for 4 h exhibit an ultralarge surface area of 358.1 m2/g and comprise numerous micropores and small mesopores (∼3.31 nm), rendering the fabricated LIB with high current density, rate capacity, cycle performance, and Li+ transfer rate. A superior electrochemical reversible specific capacity of 128.6 mAh/g can be attained over 1000 cycles of charge/discharge processes at 1C rate. Our simple and general synthesis strategy is promising for the rational design of various photostable materials with improved crystallinity, tunable crystal phases, large surface area, and applicable pore size.

Construction of multiple electromagnetic loss mechanism for enhanced electromagnetic absorption performance of fish scale-derived biomass absorber

Biomass-derived porous carbon materials have attracted considerable attention as promising electromagnetic (EM) wave absorbers due to their lightweight characteristic, ultra large surface area as well as high dielectric loss. However, the dielectric loss alone is difficult to achieve high EM wave absorption performance. In this work, core-shell Co@Co3O4/porous carbon composites are designed and synthesized by a facile hydrothermal and subsequent pyrolysis process through using fish scale as carbon precursor, Co(NO3)2·6H2O as Co source, aiming to offer more loss mechanism and achieve high EM wave absorption performance. As expected, the as-prepared composite showed strong absorption (−89.3 dB at 2.4 mm) with broadened bandwidth (11.92–18 GHz at 2 mm). Such excellent absorption performance could be attributed to the reasonable design of composite. Special porous structure not only is beneficial to the impedance matching to allow EM wave to enter absorber as much as possible, but also could offer a conductive path for electronic, booming conductive loss. Besides, the designed unique core-shell structure provides Co-Co3O4 interfaces along with Co3O4-C, C-void interfaces are propitious to enhance interface polarization loss. Moreover, Co@Co3O4 nanoparticles could also supply the magnetic loss to composites to further absorb EM wave from another point. Although there are many previous works about Co@Co3O4 have been reported, little works have been done on the composites of biomass porous carbon with core-shell Co@Co3O4 with such excellent EM wave absorption performance. This work indicates that the as-obtained core-shell Co@Co3O4/C could be a candidate for dealing with the increasing EM wave pollution.

Functional Graphene Derivatives for Chemotherapy-Based Synergistic Tumor Therapy

Starting from simplex drug delivery system, the graphene oxide (GO) and reduced GO (rGO) materials have been developed to be “combo” nanoplatforms containing multiple therapeutic modalities, such as the targeted drug delivery, imaging, as well as photothermal therapy (PTT) due to their distinctive physical/chemical and optical properties including excellent biocompatibility, modifiable active groups, ultra-large surface area, and intense photothermal effect. The graphene-based nanoplatforms were used for the stimuli-responsive nanocarriers, showing excellent therapeutic effects activated by endogenous stimuli including low pH, overexpressed enzymes, biomolecules, elevated glutathione, and exogenous stimuli including light, magnetic/electric field, and ultrasound. More importantly, for multimodal synergistic therapy originated from the enhanced collaborative interactions among several monotherapy types, the obtained remarkable super-additive effects were not the results just through single therapy or their theoretical combination. In this review, the recent progresses of smart graphene-based nanoplatforms for integrated cancer therapy and bio-imaging are presented. Current challenges and future perspectives of graphene-based nanoplatforms in the biomedical field are also discussed.

Strategic use of nanotechnology in drug targeting and its consequences on human health: A focused review.

Since the development of first lipid-based nanocarrier system, about 15% of the present pharmaceutical market uses nanomedicines to achieve medical benefits. Nanotechnology is an advanced area to meliorate the delivery of compounds for improved medical diagnosis and curing disease. Nanomedicines are gaining significant interest due to the ultra small size and large surface area to mass ratio. In this review, we discuss the potential of nanotechnology in delivering of active moieties for the disease therapy including their toxicity evidences. This communication will help the formulation scientists in understanding and exploring the new aspects of nanotechnology in the field of nanomedicine.

Covalent organic frameworks derived hollow structured N-doped noble carbon for asymmetric-electrolyte Zn-air battery

We report a relatively low-temperature molten salt strategy to prepare hollow structured N -doped noble carbon (h-NNC) with highly desirable features of ultra-large surface area (1957 m2 g−1) and high graphitization, endowing the h-NNC with high activity toward catalysis of oxygen reduction reaction in acidic medium. The h-NNC is applied as cathode catalyst of an asymmetrical-electrolyte Zn-air battery, which exhibits an open circuit voltage of 2.11 V, a power density up to 270 mW cm−2, and an energy density of 1279 W h kg−1, behaving advantages over the conventional Zn-air batteries.

Synergetic promotional effect of oxygen vacancy-rich ultrathin TiO2 and photochemical induced highly dispersed Pt for photoreduction of CO2 with H2O

The ultrathin TiO2 nanosheets (TiO2-U) with abundant defects were successfully fabricated as substrates to support well-dispersed Pt nanoparticles with low metal loading by photochemical route (P), with impregnated Pt/TiO2-U, Pt/TiO2-bulk and photoreduced Pt/TiO2-bulk as control samples, to focus on studying the inductive effect of oxygen vacancy-rich ultrathin TiO2 on highly dispersed Pt nanoparticles, and their synergetic promotional effect for CO2 photoreduction. As expected, P-Pt/TiO2-U exhibited excellent photocatalytic efficiency for the selective conversion of CO2 into CH4 and CO. The ultrathin TiO2 nanosheets with a large number of low coordinative sites and ultralarge surface area promoted the rate of electron-transfer. The ultrafine Pt nanoparticles induced by photochemical strategy facilitated the efficient separation of electron–hole pairs. Furthermore, the synergy of metal and support improved the adsorption ability of CO2. These three factors were considered to drive jointly the enhancement of catalytic performance in this system. This work offers deep insights for the design of highly efficient catalysts with coordinatively unsaturated sites for CO2 photoconversion in the presence of H2O.

Omnipotent phosphorene: a next-generation, two-dimensional nanoplatform for multidisciplinary biomedical applications.

Phosphorene, also known as single- or few-layer black phosphorus (FLBP), is a new member of the two-dimensional (2D) material family and has attracted significant attention in recent years for applications in optoelectronics, energy storage and biomedicine due to its unique physicochemical properties and excellent biocompatibility. FLBP is regarded as a potential biological imaging agent for cancer diagnosis due to its intrinsic fluorescence (FL) and photoacoustic (PA) properties and negligible cytotoxicity. FLBP-based photothermal and photodynamic therapies have emerged with excellent anti-tumour therapeutic efficacies due to their unique physical properties, such as near-infrared (NIR) optical absorbance, large extinction coefficients, biodegradability and reactive oxygen species (ROS) or heat generation upon light irradiation. Furthermore, FLBP is a promising drug delivery platform because of its high drug-loading capacity due to its puckered layer structure with an ultralarge surface area, and FLBP is size-controllable with facile surface chemical modification. Because of the marked advantages of FLBP nanomaterials in biomedical applications, an overview of the latest progress and paradigms of FLBP-based nanoplatforms for multidisciplinary biomedical applications is presented in this tutorial review.

Fabrication of hollow-structured FeOx-MnOx oxidative catalysts with ultra-large surface area

In this work, hollow-structured MnOx and FeOx-MnOx were synthesized by self-template route and applied for CO oxidation. FeOx-MnOx exhibited better catalytic activity than MnOx. It could convert 79.1% CO at 20°C and had a higher CO conversion during the temperature ramping. The FeOx species could react with HCl and greatly helped to increase the specific surface area (428.5m2g−1) and pore volume (0.82cm3g−1) of the catalyst. The reserved FeOx in the FeOx-MnOx sample enhanced the redox properties and increased the amount of reactive oxygen species.

Bifunctional MOF‐Derived Carbon Photonic Crystal Architectures for Advanced Zn–Air and Li–S Batteries: Highly Exposed Graphitic Nitrogen Matters

Nitrogen‐rich porous carbons (NPCs) are the leading cathode materials for next‐generation Zn–air and Li–S batteries. However, most existing NPC suffers from insufficient exposure and harnessing of nitrogen‐dopants (NDs), constraining the electrochemical performance. Herein, by combining silica templating with in situ texturing of metal–organic frameworks, a new bifunctional 3D nitrogen‐rich carbon photonic crystal architecture of simultaneously record‐high total pore volume (13.42 cm3 g−1), ultralarge surface area (2546 m2 g−1), and permeable hierarchical macro‐meso‐microporosity is designed, enabling sufficient exposure and accessibility of NDs. Thus, when used as cathode catalysts, the Zn–air battery delivers a fantastic capacity of 770 mAh gZn−1 at an unprecedentedly high rate of 120 mA cm−2, with an ultrahigh power density of 197 mW cm−2. When hosting 78 wt% sulfur, the Li–S battery affords a high‐rate capacity of 967 mAh g−1 at 2 C, with superb stability over 1000 cycles at 0.5 C (0.054% decay rate per cycle), comparable to the best literature value. The results prove the dominant role of highly exposed graphitic‐N in boosting both cathode performances.

Three-dimensional ZnFe2O4@MnO2 hierarchical core/shell nanosheet arrays as high-performance battery-type electrode materials

In this paper, a highly ordered three-dimensional ZnFe2O4@MnO2 core/shell nanosheet arrays (ZnFe2O4@MnO2 NSAs) on three-dimensional (3D) Nickel foam (Ni foam) have been prepared via a facile, stepwise hydrothermal approach and further investigated as a battery-type electrode material. It is found that the honeycomb-like ZnFe2O4@MnO2 NSAs have outstanding electrochemical performances using cyclic voltammetry (CV), galvanostatic charge-discharge (CD), and electrochemical impedance spectroscopy (EIS) in a three-electrode system. Based on the unique nanostructure, the ZnFe2O4@MnO2 NSAs exhibit an exceptional capacity of 1084 C g−1 at current density of 2 A g−1 and long-term capacity retention of 96.1% after 5000 cycles at current density of 4 A g−1. Moreover, the ZnFe2O4 nanosheet arrays (ZnFe2O4 NSAs) also have 714 C g−1 at a current density of 2 A g−1 exhilaratingly and the capacity value is proven to be the highest when compared with other structures of ZnFe2O4 taken from the other literatures. Some synergistic effects are identified to be responsible for the observations: Firstly, high crystalline quality of the ZnFe2O4 NSAs core which is directly grown on 3D Nickel foam (a conductive current collector), allowing fast electron transport; secondly, the unique structure of honeycomb-like MnO2 shell that has an ultralarge surface area for electrochemical reaction; thirdly, smart combination of ZnFe2O4 and MnO2 effectively utilizes their different virtues and also compensate their defects; finally, highly conductive 3D Ni foam substrate, which fully eliminate conductive additives and binders.

NO catalytic oxidation over an ultra-large surface area LaMnO3+δ perovskite synthesized by an acid-etching method

After etched by acid solution, abundant cationic vacancies appear in A sites of the perovskite structure, leading to a loose structural framework which may contribute the extra surface area, the formation of oxygen vacancies and Mn4+.

Graphene oxide-based polyethersulfone core–shell particles for dye uptake

Graphene oxide (GO), a graphene nanomaterial with great application potential, possesses promising adsorption abilities towards various water contaminants due to the ultra-large surface area and the nature of electric charge on the surface.