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In this study, the influence of high temperature on corrosion resistance of steel rebars and the mechanical strength of nano-modified mortars is investigated. Two (2) different mixtures were prepared and tested in the lab; mortars containing 0.2 wt% multi-walled carbon nanotubes (MWCNTs) and mortars without nanomaterials for comparison reasons. The specimens were heated in a furnace up to 800οC for 1 h. Destructive and non-destructive tests were used to evaluate the fire resistance and durability performance of cementitious materials. In particular, the corrosion protection provided by nanomaterials was investigated using electrochemical and mass loss measurements on reinforcing steel, whilst strength tests of mortars were also carried out to evaluate their mechanical behavior after exposure in elevated temperatures. SEM and XRD techniques were used to analyze the surface and microstructure of the steel bars and mortars. The results showed, that the CNT addition slightly improves the strength and durability of mortars exposed to high temperatures as compared with the plain OPC mortar. At the same time, the corrosion resistance of steel rebars was enhanced using carbon nanotubes in mortars after exposure to high temperatures.

Metal nanomaterials (NMs) have attracted much attention from both scientific and practical perspectives. Because the crystal structure of metal NMs is a crucial factor in determining corresponding physicochemical properties, investigations of unprecedented crystal structures facilitate development of new functions and enhancement of well-known properties. Although an infinite number of crystal structures are geometrically possible, formation of experimentally known crystal structures depends on thermodynamics. Here, we introduce synthetic strategies for new frameworks of mono-metal and alloy NMs as well as unprecedented ordered structures of alloy NMs, reveal the contribution to enhanced catalysis of the hydrogen evolution and oxygen reduction reactions, and provide perspectives on catalytic properties that depend on unique crystal structures.

Hydrogen energy has long been recognized as a clean alternative to conventional fossil fuels, which can be applied in a wide range of transportation and power generation applications. The rational design and engineering of high-performance and robust catalysts for hydrogen evolution reaction (HER) shows not a great significance but a challenge for efficient electrochemical water splitting. Herein, a new type of Ni-based Ni-ABDC precursor has been obtained, which leads to the formation of N-doped porous carbon nanomaterials uniformly coated with well-proportioned bimetallic AgNi alloys via a stepwise strategy. To their credit, all samples of AgNi/NC-X are structurally calcined from the pristine AgNi-ABDC-X by tuning the different concentration of AgNO3, which means all of them maintain the vermicelli-like morphology compared with Ni-ABDC. The series of AgNi/NC-X materials can be regarded as effective electrocatalysts for HER both in acidic and alkaline media, but an acid-leaching phenomenon is observed. Among them, the as-prepared AgNi/NC-2 exhibits a low overpotential of 103 mV at the current density of 10 mA cm−2 and decent durability with a high retention rate of 90.9% after 10 h in 1.0 M KOH electrolyte. The compelling HER properties of AgNi/NC-2 can be attributed to the synergistic effect between the hierarchical carbon materials, partial N-doping and abundant AgNi alloys. Meanwhile, this study provides a practicable method for the development of efficient HER electrocatalysts for energy applications, which can be conveniently prepared through the reasonable introduction of active components in the crystalline inorganic-organic precursors.

Adsorptive removal of heavy metal ions from wastewater is very important, and the key is the development of efficient sorbents. In this work, oxygenated alkynyl carbon materials (OACMs) were synthesized via mechanochemical reaction of CaC2 and a carbonate (CaCO3, Na2CO3, or NaHCO3) at ambient temperature. The resultant OACMs are micro mesoporous carbon nanomaterials with high specific area (>648 m2 g−1), highly crosslinked texture, and rich alkynyl and oxygenated groups. The OACMs exhibit excellent Hg(II) adsorption due to the soft acid-soft base interaction between alkynyl and Hg(II), and OACM-3 derived from CaC2 and NaHCO3 has the saturated Hg(II) adsorbance of 483.9 mg g−1 along with good selectivity and recyclability. The adsorption is mainly chemisorption following the Langmuir mode. OACM-3 also shows high adsorbance for other heavy metal ions, e.g. 256.6 mg g−1 for Pb(II), 232.4 mg g−1 for Zn(II), and 198.7 mg g−1 for Cu(II). This work expands the mechnochemical reaction of CaC2 with carbonates and possibly other oxyanionic salts, provides a new synthesis approach for functional alkynyl carbon materials with excellent adsorption performance for heavy metal ions, as well as a feasible approach for CO2 resource utilization.

In the present paper, we have studied the dependence of thermal conductivity on shape, size and dimension of nanomaterial. By using the quantitative expression of melting temperature, the expression for thermal conductivity is deduced in this work. Kapitza resistance term is also considered in the study to better explain the thermal conductivity variation in nanomaterials with scattering effect on thermal properties. The thermal conductivity is found to decreased as size of nanomaterials decease. The variation in thermal conductivity with size is calculated for nanowire, nanofilm, spherical, regular tetrahedral particle, regular octahedral particle, and regular icosahedral particle shapes. The results calculated in the present work are compared with the available experimental results to judge the validity of the present model.

SnO2 has been extensively used in the detection of various gases. As a gas sensing material, SnO2 has excellent physical-chemical properties, high reliability, and short adsorption-desorption time. The application of the traditional SnO2 gas sensor is limited due to its higher work-temperature, low gas response, and poor selectivity. Nanomaterials can significantly impact gas-sensitive properties due to the quantum size, surface, and small size effects of nanomaterials. By applying nanotechnology to the preparation of SnO2, the SnO2 nanomaterial-based sensors could show better performance, which greatly expands the application of SnO2 gas sensors. In this review, the preparation method of the SnO2 nanostructure, the types of gas detected, and the improvements of SnO2 gas-sensing performances via elemental modification are introduced as well as the future development of SnO2 is discussed.

Heterostructure engineering of electrocatalysts provides a fascinating platform to reasonably manipulate the physicochemical properties of nanomaterials and further improve their catalytic efficiency for water electrolysis. However, it still remains a huge challenge to construct well-designed core-shell heterostructured catalysts and identify the key role of components for synergistic catalysis. Herein, a melted polymeric salt tactics was innovatively developed to synthesize heterostructured Ni@Ni(OH)2 core-shell nanomaterials supported on porous carbon (named Ni@Ni(OH)2/PC), wherein well-defined Ni(OH)2-Ni heterostructure plays a pivotal role in improving electrocatalytic activity for water reduction and oxidation. Besides, the stable porous carbon support functions as a highway for continuous electron transfer between Ni and Ni(OH)2, and simultaneously enables the full exposure of accessible active sites. The fabricated Ni@Ni(OH)2/PC exhibits outstanding bifunctional electrocatalytic performance for overall water splitting (ƞ10 = 1.55 V) with a good long-time stability. This work sheds new light on the design of engineering heterostructure of active bifunctional electrocatalysts for efficient energy conversion system.

The scaled-up synthesis of organic-free monolayer nanomaterials is highly desirable, especially in obtaining green energy by electrocatalysis. In this study, a method for the scaled-up synthesis of the series of monolayer layered double hydroxides (LDHs) without the addition of organic solvents is reported via the separate nucleation and aging steps process. The resulting monolayer LDHs with the thicknesses of less than 1 nm showed a narrow thickness distribution. X-ray absorption fine-structure revealed that monolayer NiFe-LDH nanosheets have a number of oxygen and metal vacancies defects. As a practical application, monolayer NiFe-LDH nanosheets containing defects showed an enhanced electrocatalytic water oxidation activity compared with that of bulk NiFe-LDH. Density functional theory calculations uncovered that excellent catalytic activity is attributed to vacancies defects. The proposed method is an economical and universally applicable strategy for the scaled-up production of monolayer LDHs.

Seeking for extremely active and durable bifunctional electrocatalysts towards the overall water splitting possesses a strategic significance on the development of sustainable and clean energy for the replacement of fossil fuels. Ir-based nanomaterials are deemed as one of the most high-efficiency oxygen evolution reaction electrocatalysts while the hydrogen evolution reaction performance is unfavorable. In this work, we report a one-pot hydrothermal synthesis of N-doped graphene anchored Ir nanoparticles (Ir/N-rGO) with ultrasmall particle size (∼2.0 nm). Apart from the predictably superior OER performance, the resultant Ir/N-rGO also displays excellent hydrogen evolution reaction (HER) performance, requiring merely 76 and 260 mV overpotentials to achieve the current density of 10 mA cm-2 towards HER and OER, respectively. When applied as the bifunctional electrodes for overall water splitting, Ir/N-rGO needs a lower overpotential (1.74 V) to achieve a current density of 50 mA cm-2 in alkaline solution, exceeding that of Pt/C and RuO2 couple (1.85 V). Thus, the as-fabricated Ir/N-rGO has a commendable prospect in the practical application of alkaline water electrocatalysis.

Fungi show a variety of abilities in affecting metal speciation, toxicity, and mobility and mineral formation, dissolution or deterioration through several interacting biomechanical and biochemical mechanisms. A consequence of many metal-mineral interactions is the production of nanoparticles which may be in elemental, mineral or compound forms. Organisms may benefit from such nanomaterial formation through removal of metal toxicity, protection from environmental stress, and their redox properties since certain mycogenic nanoparticles can act as nanozymes mimicking enzymes such as peroxidase. With the development of nanotechnology, there is growing interest in the application of biological systems for nanomaterial production which may provide economic benefits and a lower damaging environmental effect than conventional chemical synthesis. Fungi offer some advantages since most are easily cultured under controlled conditions and well known for the secretion of metabolites and enzymes related to nanoparticle or nanomineral formation. Nanoparticles can be formed intracellularly or extracellularly, the latter being favourable for easy harvest, while the cell wall also provides abundant nucleation sites for their formation. In this article, we focus on the synthesis of nanoparticles and nanominerals by fungi, emphasizing the mechanisms involved, and highlight some possible applications of fungal nanomaterials in environmental biotechnology.

Derivatization of 2D materials for bioapplications is at the forefront of nanomaterials research nowadays. Facile synthesis of the biografted 2D derivatives and insight into the conformation of the conjugated biomolecules are two pillars, promoting advances in the field of biosensing, drug delivery and regeneration techniques. This work is devoted to the synthesis and conjugation of carboxylated graphene by aptamers followed by theoretical analysis of their conformation in the immobilized state. Employing the developed method, the hole-matrixed graphene with up to 11.1 at.% reactive carboxyl groups was synthesized and thoroughly examined via core-level spectroscopy and time-resolved methods. The mechanism of the performed carboxylation with conversion of graphene oxide into carboxylated graphene is proposed, unveiling commonly disregarded impact of ether-like components to the fingerprints of the carboxyl groups. We show successful covalent immobilization of the AO-01 aptamer against Hepatitis B protein on the synthesized C-xy graphene and for the first time reveal its conformation both in free and immobilized forms via a combination of density functional theory (DFT) calculations and molecular dynamic (MD) modeling. Taken together, these results advance the application of graphene derivatives grafted with the biomolecules in the field of biosensing.

The work is dedicated to a research into the physicochemical aspects of carbon nanopowder production from the gas phase by the pyrolysis of the initial precursors in a cyclic adiabatic process in a flow-through chemical compression reactor (CCR). The method allows the production of carbon nanomaterials, such as the carbon nanoparticles and globular soot particles, as well, as the core-shell structures representing the 4–7 nm composite particles with a SiC crystal core covered with graphene layers. Products have controlled and reproducible properties, and output capacity of the method is sufficient for technological purposes. The nanopowders are characterized by high-resolution transmission electron (TEM) and scanning electron (SEM) microscopy, X-ray diffraction analysis and Raman spectroscopy. The nanomaterials were used to manufacture their aqueous suspensions - nanofluids, which have shown their effectiveness in enhancing oil recovery in oil displacement technologies.

Nowadays, electrochemical water splitting is a securing alternative for clean-energy production and also an efficient expertise for oxygen and hydrogen production. Compared to single metal-based electrocatalyst, multi metal-based electrocatalyst offers more active sites, high surface area, and distinctive nanostructure for effective water oxidation. In this work, nickel and cobalt co-doped MnCO3 was successfully synthesized via a facile co-precipitation technique. Rhombohedral crystal phase of MnCO3 nanostructures and its crystallite sizes were thoroughly analyzed by the XRD spectra. Incorporation of doping element such as Ni and Co in MnCO3 nanostructures exhibited two different morphologies which enhanced the catalytic performance of the prepared samples. Large surface area and porosity of the nanomaterials improved the stability and activity of the prepared MnCO3 nanostructures. EDX analysis confirmed Mn, C, O, Ni and Co elements in stoichometric ratio. Moreover, the specific capacitance of (Ni, Co) co-doped MnCO3 nanostructures attained 581 F/g while the other electrodes attained only 207, 332 and 175 F/g respectively. A small Tafel slope with low overpotential of Ni, Co co-doped MnCO3 nanostructures was 20.2 mV/dec and 293 mV respectively. Therefore, the prepared electrocatalysts of Ni, Co co-doped MnCO3 nanostructure is one of the attractive anode material for high performance energy conversion applications.

Nanozymes are inorganic nanoparticles with enzyme-like features. Noble metals and metal oxide-based nanomaterials can present enzyme-mimicking behavior mediating catalytic reactions including oxidase-, peroxidase-, catalase-, and superoxide dismutase-like activities with important applications in environmental and biomedical grounds. Thus, in this study, it was designed and developed a novel nanosystem that exploits the oxidase-like (OD) behavior of gold nanoparticles (AuNPs, GOLDzyme) and the peroxidase-like (POD) characteristics of cobalt-doped magnetic iron oxide nanoparticles (MIONs, Co-MIONzyme) amalgamated in an inorganic-inorganic bi-nanozyme cascade for the degradation of dye pollutants. GOLDzyme and Co-MIONzyme nanomaterials were synthesized and stabilized by citrate and carboxymethylcellulose (CMC) ligands, respectively, using a green aqueous colloidal process at mild conditions. The physicochemical characterization results indicated that water-dispersible colloidal supramolecular nanostructures were effectively produced, with core-shell morphologies (i.e., inorganic nanoparticle core/organic-shell). The AuNPs (GOLDzyme) presented crystalline nanostructure, with a uniform spherical shape, zeta potential (ZP) = - 46 ± 3 mV, hydrodynamic diameter (DH) = 11 ± 3 nm. Analogously, the Co-MIONzyme stabilized by CMC ligand evidenced the formation of nanocrystalline substituted magnetite (CoxFe3-xO4) with uniform spherical morphology, average size = 7.0 ± 2 nm, ZP = - 47 ± 3 mV, DH = 46 ± 3 nm, and superparamagnetic behavior. When tested separately using a colorimetric assay based on a chromogenic molecule (3,3',5,5’ tetramethylbenzidine, TMB), they demonstrated catalytic activity upon the injection of each specific substrate in the medium, i.e., glucose for GOLDzyme that behaved predominantly as oxidase-like nanomaterial, and H2O2 for Co-MIONzyme, which showed a peroxidase-like or catalase-like behavior. In addition, these nanozymes demonstrated pH-dependent and temperature-dependent catalytic activities. As a proof of concept, when combined into a single-pot reaction system, these bifunctional nanozymes confirmed integrated catalytic cascade as oxidase and peroxidase-like nanocatalysts towards the oxidation of TMB and the degradation of methylene blue (MB, ~18%) as the model dye pollutant. Based on the preliminary encouraging results of this research, it can be foreseen that the combination of nanozymes paves the way for the development of new nanoplatforms for prospective applications in water treatment and environmental remediation.

Lanthanide-doped upconversion nanoparticles (Ln-UCNPs) are a new type of nanomaterials with excellent fluorescence properties, which are well applied in fluorescent biosensing. Herein we developed a multifunctional probe based on the surface engineering of core-shell structure UCNPs with polyacrylic acid (PAA). The developed PAA/UCNPs probe could be highly selective to detect and respond to Cu2+ at different pH. Cu2+ could easily combine with the carboxylate anion of PAA to quench the fluorescence of UCNPs. Therefore, we creatively proposed a fluorescent array sensor (PAA/UCNPs-Cu2+), in which the same material acted as the sensing element by coupled with pH regulation for pattern recognition of 5 thiols. It could also easily identify the chiral enantiomer of cystine (L-Cys and D-Cys), and distinguish their mixed samples with different concentrations, and more importantly, it could be combined with urine samples to detect actual level of homocysteine (Hcys) to provide a new solution for judging whether the human body suffers from homocystinuria.

Cellulose and its derivatives are natural materials with high carbon contents, but it is challenging to convert their carbon into high value-added carbonaceous materials (e.g., graphene). Here, an approach to convert the carbon in cellulose into N, P co-doped porous graphene (LIG) materials via laser induction is proposed. Cellulose nanofibrils (CNFs), a cellulose derivative with high dispersion uniformity and abundant surface hydroxyl groups, were easily formed on a bulk substrate (thickness ≥ 5 mm) containing ammonium polyphosphate (APP). Then, a 10.6 μm CO2 laser was used to scribe for 1–5 passes on the CNFs/APP substrate under an ambient environment to produce N, P co-doped porous LIG. Upon increasing the number of laser scribing passes, the IG/ID of LIG first increased and then decreased, reaching a maximum of 1.68 at 4 passes. The good pore structure and low resistance also showed that 4 laser passes were ideal. Besides, the N, P co-doped LIG also showed excellent electrochemical performance, with a specific capacitance of 221.4 F/g and capacitance retention of 89.9%. This method exploits the advantages of nanocellulose and overcomes the difficulties associated with directly compounding cellulosic materials, providing a method for the further development of biomass nanomaterials.

The effect of gold nanoparticles supported on V2O5/TiO2 nanomaterials prepared by different routes and its activity in the CO oxidation at low temperature were studied. The catalysts were characterized by N2 physisorption, X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). This study showed that the sol-gel Au-V2O5/TiO2 material exhibited higher catalytic activity after a thermal treatment at 400 °C in hydrogen than Au-V2O5/NT nanotubes, Au-V2O5/P25 Evonik and V2O5/TiO2 nanomaterials. The sol-gel Au-V2O5/TiO2 catalyst was also more active than Au/TiO2. These results could be explained by the fact that the gold species (Au° and Au1+) improved the interaction between vanadium species and TiO2, allowing high vanadium oxidation states (from V3+ to V5+) through a charge transfer effect between the support surface and Au-VOx reactive species; the presence of monovanadate and Ti3+ species led to remarkable activity in the CO oxidation from 0 °C in comparison with Au/TiO2.

Metallic element release during implant placement can lead to mucositis and peri-implantitis. Here, using ex vivo porcine mandibles, the release of metallic elements into the surrounding bone with different material and geometrical designs was quantified. Implants from BioHorizons® and Straumann® (Bone level, tapered/cylindrical, 3/4 mm body diameter, Ti-CP4/Ti-6Al-4V/Ti-15Zr) systems were used. Micro computed tomography and inductively coupled plasma optical emission spectroscopy was used to visualise and quantify metallic elements in bone, following acid digestion. Implant surfaces were examined with scanning electron microscopy and internalization of implant particles by human gingival fibroblasts (HGFs) and RAW 264.7 macrophages were demonstrated in vitro. Implants with wider body diameters resulted in higher metallic element release. Ti-6Al-4V implants released significantly more metallic elements in comparison to both Ti-CP4 and Ti-15Zr devices with similar design and dimensions. Tapered Ti-CP4 implants released less compared to those with cylindrical design. Al three types of particles were internalized by HGFs and RAW 264.7. Ti-CP4 and Ti-15Zr appear to be more suitable materials, however, further studies are required to elucidate the biological effects of the fine particles and/or metallic species from dental implants. Authors would like to raise the awareness in the dental profession community that careful evaluation of the materials used in dental implants and the potential risks of the individual constituents of any alloy are needed. The potential cytotoxicity of Ti-6Al-4V implant particles should be highlighted. Further investigations on the biological effect of the fine particles or metallic species released from dental implants are also needed. [Abstract copyright: Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.]

Due to its unique advantages, which include minimal invasiveness and relative clinical safety, phototherapy is considered to be a promising approach for cancer treatment. However, the treatment efficacy of phototherapy is often restricted by the limited depth of light penetration and the low targeting effect of phototherapeutic agents. The emergence of light-responsive nanomaterials offers a possible approach to achieve enhanced phototherapy potency. This review summarizes the progress in biomedical applications of light-responsive nanomaterials for cancer therapy, which include photothermal therapy (PTT), photodynamic therapy (PDT), light-responsive molecule delivery, and light-controlled combination therapy. Future prospects are also discussed. This review aims to demonstrate the significance of light-responsive nanomaterials in cancer therapy and to provide strategies to expand the applications of phototherapy.

Nanomaterials are beginning to play an essential role in addressing the challenges associated with hydrogen production and storage. The outstanding physicochemical properties of nanomaterials suggest their applications in almost all technological breakthroughs ranging from catalysis, metal-organic framework, complex hydrides, etc. This study outlines the applications of nanomaterials in hydrogen production (considering both thermochemical, biological, and water splitting methods) and storage. Recent advances in renewable hydrogen production methods are elucidated along with a comparison of different nanomaterials used to enhance renewable hydrogen production. Additionally, nanomaterials for solid-state hydrogen storage are reviewed. The characteristics of various nanomaterials for hydrogen storage are compared. Some nanomaterials discussed include carbon nanotubes, activated carbon, metal-doped carbon-based nanomaterials, metal-organic frameworks. Other materials such as complex hydrides and clathrates are outlined. Finally, future research perspectives related to the application of nanomaterials for hydrogen production and storage are discussed.

MnOx-Fe3O4 nanomaterials were fabricated by using the innovative scheme of pyrolyzing manganese-doped iron-based metal organic framework in inert atmosphere and exhibited extraordinary performance of NO reduction by CO (CO-SCR). Multi-technology characterizations were conducted to ascertain the properties of fabricated materials (e.g., TGA, XRD, SEM, FT-IR, XPS, BET, H2-TPR and O2-TPD). Moreover, the interaction between reactants and catalysts was ascertained by in situ FT-IR. Experimental results demonstrated that Mn was an ideal promoter for iron oxides, resulting in decrease of crystallite size, improve reducibility property, enhance the mobility and the amount of lattice O2– species, as well as strength the adsorption ability of active NO and CO to form multiple species (e.g., nitrate and carbonate). The unprecedented enhancement of CO-SCR activity over Mn-Fe nanomaterials follows the Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) reaction pathway.

The creation of an environmentally friendly synthesis method for silver nanomaterials (AgNPs) is an urgent concern for sustainable nanotechnology development. In the present study, a novel straightforward and green method for the preparation of silver nanoparticle/reduced graphene oxide (AgNP/rGO) composites was successfully developed through the combination of phytosynthesis, continuous flow synthesis and microwave-assistance. Oriental persimmon (Diospyros kaki Thunb.) extracts were used as both plant reducing and capping agents for fast online synthesis of AgNP/rGO composites. The experimental parameters were optimized and the morphologies of the prepared materials were investigated. The characterization results reveal that spherical AgNPs were quickly synthesized and uniformly dispersed on rGO sheets using the proposed online system. Fourier transform infrared spectroscopy analysis confirmed that phenols, flavonoids, and other substances in the plant extracts played a decisive role in the synthesis of AgNP/rGO composites. Using sodium borohydride (NaBH4) degradation of p-nitrophenol (4-NP) as a model, the catalytic activity of the prepared AgNP/rGO materials was evaluated. The complete degradation of 4-NP was achieved within 12 min through the use of AgNP/rGO materials, and the composite had a much better catalytic activity than the bare AgNPs and rGO had. Compared with the conventional chemical method, our online method is facile, fast, cost-efficient, and environmentally friendly.

Conformational regulation among two or more distant sites is not only one of the main pathways to accomplish multiple tasks in complex biological systems but also represents a powerful strategy to obtain stimuli-responsive supramolecular nanoconstructs with tailored physicochemical performance. We herein report the fabrication of a photochromic supramolecular assembly, which can be synergistically activated by the conformational regulation with bis(4,8-disulfonato-1,5-naphtho)-32-crown-8 and then reversibly switched by the through-space communication between restricted stilbazolium salt and photochromic dithienylethene. This work demonstrates that the synergistic conformational modulation via intra- and intermolecular interactions can be developed as a generalizable approach to construct more advanced biomimetic nanomaterials.

Perovskite solar cell (PSC) has gradually shown its great superiority in photovoltaic filed to compete commercial solar cells owing to its great advantages, such as high efficiency and low fabrication cost. On the way towards commercialization, great efforts have been achieved by accelerating charge extraction and reducing carrier recombination. Recently, two-dimensional (2D) layered materials have attracted increasing interests for application in PSCs due to their distinctive chemical and physical properties, such as high carrier mobility and tunable bandgap, which greatly determines the perovskite film growth kinetics, carrier transfer and stability of PSCs. Therefore, with the aim to better understand their recent development and application in PSC, in this review, the emerging 2D materials beyond graphene as charge transport layers, buffer layers and additives in perovskite film for enhancing the efficiency and stability of PSCs are summarized. However, there are still some crucial challenges to be addressed for commercialization. Finally, the challenges and prospects of these 2D nanomaterials for application in PSCs are further proposed for future development.

2D nanomaterials are widely investigated for biomedical applications, attributed to their large specific surface area, high therapeutic loading capacity, and unique optical, thermal, and/or electronic characteristics. Lattice defects affect the theranostic performance of 2D nanomaterials significantly by altering their electronic properties and chemical binding. Recent investigations have shown that defect-rich 2D nanomaterials are capable of enhancing tumor treatment through efficient drug delivery, photothermal and photodynamic therapies (PTT and PDT), and improving diagnostics via computed tomography (CT), photoacoustic and magnetic resonance imaging. This review summarizes recent progresses, including synthesis, characterization approach, and applications of defect-engineered 2D nanomaterials that are potentially useful in cancer treatment. The expert opinions are also proposed as the conclusion.

Fe3O4-based materials are widely used for magnetic separation from wastewater. However, they often suffer from Fe-leaching behavior under acidic conditions, decreasing their activity and limiting sustainable practical applications. In this study, covalent organic frameworks (COFs) were used as the shell to protect the Fe3O4 core, and the Fe3O4@COF core-shell composites were synthesized for As(III) removal from acid wastewater. The imine-linked COFs can in situ grow on the surface of the Fe3O4 core layer by layer with [COFs/Fe3O4]mol ratio of up to 2:1. The Fe-leaching behavior was weakened over a wide pH range of 1-13. Moreover, such composites keep their magnetic characteristic, making them favorable for nanomaterial separation. As(III) batch adsorption experiments results indicated that, when COFs are used as the shell for the Fe3O4 core, a balance between As(III) removal efficiencies and the thickness of the COF shell exists. Higher As(III) removal efficiencies are obtained when the [COFs/Fe3O4]mol ratios were

As a new type of carbon-based fluorescent nanomaterials, carbon dots (CDs) are provided with the advantages of small size, excellent photoluminescence (PL) property, easy surface modification, robust stability, good water solubility and biocompatibility, which endow them with great potential in sensing. In this review, we first describe the preparation of CDs from different starting materials via various techniques, and pre-/post-modification strategies to modulate their PL properties. Second, we outline the optical properties of CDs, including UV-vis absorption and PL, especially the PL mechanisms of CDs are presented in detail from the size effect, molecular state, surface state and defect state. Third, we summarize the research progress of CDs in sensing environmental pollutants, bioactive substances, biological microenvironments, bacteria and viruses via different mechanisms. In addition, we envision the future development trends and prospects for CDs-based nanosensors. We believe that this type of small nanoparticles will bring about big prospect in the near future.

The need to develop specific-morphology nanomaterials to produce dimethyl ether (DME), a promissory alternative fuel, by the catalytic methanol dehydration has triggered extensive research to synthesize novel materials. In this work mesoporous Al-MCM-41 nanospheres with variable size (35−90 nm) were synthesized by the sol-gel method. The size of the Al-MCM-41 nanospheres was controlled by adjustable NaOH/TEOS ratio (0.2−0.5). The Al-MCM-41 nanospheres were characterized by TPD, TEM, XRD, EDX, XPS and N2-physisorption. According to the characterization results the Al ions were successfully incorporated in the MCM-41 framework and the Al-MCM-41 nanospheres showed hexagonal and mesoporous structure. Additionally, it was observed that the higher the NaOH/TEOS ratio the smaller size of the nanosphere and, smaller Al-MCM-41 nanospheres presented more amount of medium acidic sites on its surface. The catalytic activity results showed that all samples tested reached 100% of selectivity towards DME. The smallest Al-MCM-41 nanospheres achieved 78% of DME yield at 300 °C and good catalytic activity performance below to 300 °C. The stability of the fresh and regenerated Al-MCM-41 nanospheres was evaluated for 48 h time-on-stream. High values of DME yield (> 60%) were maintained during 48 h time-on-stream showing the possibility for recycling the material.

Benefiting from their high concentration of in-plane nitrogen element, superior chemical/thermal stability, tunable electronic band structure and environmental friendly feature, graphite-like carbon nitride (g-C3N4) as a new promising metal-free material has drawn numerous attention in photo-/electric-catalysis. Comparing to the regulation of band structure in photocatalysis, the deliberately synthesis of g-C3N4 electrocatalysts is mainly focused on the construction of catalytic sites and the modulation of the charge transfer kinetics. Herein, this work reports a rapid method for synthesizing ultrafine g-C3N4 quantum dots (QDs) via electrochemical exfoliation using Al3+ ions. The uniform g-C3N4 QDs with smaller lateral dimension and thickness are collected due to the higher charge density and stronger electrostatic forces of Al3+ ions in the lattice of host materials as compared to the conventional univalent alkali cations. The as-obtained g-C3N4 QDs exhibit average lateral dimension and thickness of 3.5 nm and 1.0 nm, respectively, as determined by the TEM and AFM measurements. Also, the presence of the rich C/N defects is verified by the UV-vis spectra. Encouragingly, the ultrafine g-C3N4 QDs exhibit superior hydrogen evolution reaction (HER) performance with an ultra-low onset-potential closely approaching to 0 V, and a low overpotential of 208 mV at 10 mA/cm2, as well as a remarkably low Tafel slope (52 mV·dec-1) in acidic electrolyte. Taking the fabrication of the ultrafine g-C3N4 QDs with rich C/N defects as an example, this work provides a simple and feasible way to exfoliate 2D layered materials into low-dimensional nanomaterials towards highly-efficient electrocatalysis, as well as the exploration of their fascinating physic-chemical properties.

Surface modification by hydrophilic functional group have a tremendous influence on the catalytic activity of photocatalyst, however, there are few reports on improving piezoelectric catalytic performance through surface functionalization. Herein, OH-modified SrTiO3 was successfully obtained via a novel low-temperature solid-state precursor method and employed as a catalyst for photocatalytic, piezocatalytic and piezo-photocatalytic hydrogen production. Thanks to the super hydrophilic that is facilitating the contact of catalyst and water molecular and the more oxygen vacancies that can promote electron-hole separation, the photocatalytic, piezocatalytic and piezo-photocatalytic hydrogen generation of OH-modified SrTiO3 (OH-STO) is about two times higher than pristine SrTiO3 (STO). It is worth mentioning that the optimal piezo-photocatalytic hydrogen evolution rate of OH-STO (701.2 µmol h-1 g-1) is 5.3 times higher than the photocatalytic hydrogen evolution process of STO. This study presents a low-energy approach to the rational design of functional group modification nanomaterials that possess excellent piezo-photocatalytic performance.

An array of new nanomaterials have been designed to mimic the catalyst characteristics of natural enzymes (termed "nanozymes"), which connects an essential bridge between nanotechnology and biomedical science. Thus, the research on nanozymes has increased dramatically and a new multidisciplinary field has emerged in recent years named nanozymology. Magnetic iron oxide nanoparticles (e.g., Fe2O3 and Fe3O4, MIONs) have revealed to perform an enzyme-like activity with pH-dependent behavior. These nanozymes can catalytically decompose H2O2 into products (e.g., H2O and O2) under mild pH conditions mimicking enzyme-like bioactivity. More importantly, under mildly acidic conditions, they can use H2O2 as the substrate for producing highly toxic reactive oxygen species (ROS) through the generation of hydroxyl radicals ( OH), displaying peroxidase-like activity. Therefore, here we designed and developed a novel class of hybrid nanocatalysts based on the conjugation of GOx (natural enzyme) and MIONs (inorganic nanozyme) stabilized by a biocompatible polymer shell of carboxymethyl cellulose. They created supramolecular vesicle-like nanostructures that were tested for killing brain cancer cells (U-87 MG) in vitro, where they proved anticancer activity attributed to ferroptosis-induced cell death. These hybrid nanostructures performed as a cascade of integrated nanocatalysts: a) GOx worked as the starting catalyst, where the glucose in the medium generated H2O2; b) next, H2O2 was catalyzed by the downstream MION nanozymes (Fe3O4) via Fenton-like reactions releasing toxic species (ROS), which caused the cancer cell death. Remarkably, this nanozyme-induced cell death was more pronounced in brain cancer cells ascribed to the more acidic microenvironment than on healthy cells.

Lanthanide ions doped luminescent materials are widely studied for latent fingerprint detection. However, most of these materials are synthesized at very high temperatures and use UV C light for visualization, which is harmful to eye, skin, etc. Herein, the Gd0.95Eu0.05PO4 nanorods synthesized by a simple co-precipitation method at 185 °C were reported for latent fingerprint visualization under 395 nm light. The Gd0.95Eu0.05PO4 nanomaterial has monoclinic crystal structure and shows rod-shaped morphology. Further, these Gd0.95Eu0.05PO4 nanorods exhibit excellent photoluminescence properties and strong fuchsia emission under UV light. These nanorods have been employed for developing latent fingerprints on various porous and non-porous substrates by the powder dusting technique, which exhibits clear and well defined details with high contrast, selectivity and sensitivity under 395 nm UV light. Latent fingerprints developed after 72 h of their deposition also show clear contrast with these nanorods. Therefore, the Gd0.95Eu0.05PO4 nanorods can be used for latent fingerprint visualization applications.

To significantly improve the electrochemical performance of tin-based materials as anodes for lithium ion batteries, hybridizing tin-based nanomaterials with carbon is an effective way. This is due to carbon materials serving not only as conductive networks to increase the electrical conductivity, but also as construct void to buffer volume expansion. However, the use of excess carbon in hybrids and the low lithium storage ability of the carbon could lead to the reduced total capacity of the electrode. Herein, we develop a simple and effective approach to the synthesis of EG/SnO2-x in which SnO2 nanoparticles are tightly anchored on the surface of expanded graphite (EG) with well-defined expanded structures and highly conductive frameworks. Benefiting from the rational mass loading of SnO2, as well as the high conductivity and strong lithium storage characteristic of EG, the EG/SnO2-3 hybrid displays outstanding electrochemical performance with excellent rate capability (e.g., 406.3 mAh g–1 at 1 A g−1) and long cycling stability (e.g., 262.7 mAh g−1 over 500 cycles). In particular, the large proportion of capacity secured from a narrow voltage range of 0.01–0.3 V, corresponding to a low average working potential, is vital for the hybrids applied in high voltage full-cell LIBs.

Hydrogen energy could be a economic and powerful technology for sustainable future. Producing hydrogen fuel by electrochemical water splitting has attracted intense interest. Due to their physical and chemical properties, two-dimensional (2D) nanomaterials have sparked immense interest in water electrocatalysis for hydrogen production. This review focuses on the emerging nanocatalysts in 2D nanoarchitectures for electrocatalytic hydrogen production. The fundamentals of HER are firstly depicted, following the discussion of recent advances in typical 2D electrocatalysts for HER. The insights into the relationship among the synthetic protocols, structure, catalytic performance and thermodynamics will be discussed in details. Finally, the outlooks regarding further development of 2D nanocatalysts for HER are proposed. We hope this review will offer a comprehensive understanding in 2D nanocatalysts to promote electrochemical hydrogen production.

To inhibit the agglomeration of tin-based nanomaterials and simplify the complicated synthesis process, a facile and eco-friendly self-formed template method is reported to synthesize tin submicron spheres dispersed in nitrogen-doped porous carbon (Sn/NPC) by pyrolysis of a mixture of disodium stannous citrate and urea. The vital point of this strategy is the formation of Na2CO3 templates during pyrolysis. This self-formed Na2CO3 acts as porous templates to support the formation of NPC. The obtained NPC provides good electronic conductivity, ample defects, and more active sites. Serving as anode for Li-ion batteries, the Sn/NPC electrode obtains a stable discharge capacity of 674.1 mAh/g after 150 cycles at 0.1 A/g. Especially, a high discharge capacity of 331.2 mAh/g can be achieved after 1100 cycles at 3 A/g. Additionally, a full cell coupled with LiCoO2 as cathode yields a discharge capacity of 524.8 mAh/g after 150 cycles at 0.1 A/g. In-situ XRD is implemented to investigate the alloying/dealloying reaction mechanisms. Density functional theory calculation ulteriorly explicates that NPC heightens intrinsic electronic conductivity, and NPC especially pyrrolic-N and pyridinic-N doping facilitates the Li-adsorption ability. Climbing image nudged elastic band method reveals low Li+ diffusion energy barrier in presence of N atoms, which accounts for the terrific electrochemical properties of Sn/NPC electrode.

Immobilizing primary electroactive nanomaterials in porous carbon matrix is an effective approach for boosting the electrochemical performance of potassium-ion batteries (PIBs) because of the synergy among functional components. Herein, an integrated hybrid architecture composed of ultrathin Cu3P nanoparticles (~20 nm) confined in porous carbon nanosheets (Cu3P⊂NPCSs) as a new anode material for PIBs is synthesized through a rational self-designed self-templating strategy. Benefiting from the unique structural advantages including more active heterointerfacial sites, intimate and stable electrical contact, effectively relieved volume change, and rapid K+ ion migration, the Cu3P⊂NPCSs indicate excellent potassium-storage performance involving high reversible capacity, exceptional rate capability, and cycling stability. Moreover, the strong adsorption of K+ ions and fast potassium-ion reaction kinetics in Cu3P⊂NPCSs is verified by the theoretical calculation investigation. Noted, the intercalation mechanism of Cu3P to store potassium ions is, for the first time, clearly confirmed during the electrochemical process by a series of advanced characterization techniques.

Over the past few decades, the study of superhydrophobic coatings (SHCs) gained the significant interest of worldwide researchers due to their tremendous applications in various sectors including, the metal industry, membrane industry, automation, structures, marine, defense, and medicines. The literature is full of review papers on the basics of SHCs, their synthesis methods, and their applications. But, minimal reviews are available on silica nanoparticles-based SHCs. However, silica nanoparticles are well-known material for SHCs due to their abundance, economical, transparency and ease of surface modification by various surface-functionalizing agents compared to other nanomaterials. Furthermore, silica nanoparticles are the most preferred material for the generation of nano-level roughness in the coatings to exhibit superhydrophobicity. Therefore, there is a great need to work in this direction. This work is dedicated to the challenges, recent progress and applications of silica nanoparticles-based superhydrophobic coatings.

Facile strategy enabling the fabrication of carbon dots (CDs) with favorable performance useful for various applications is highly desirable. Here, we report the fabrication of highly fluorescent carbon dots (CDs) towards sensitive metal ion detection, brightly fluorescent printing pattern, as well as green flame retardants for synthetic polymeric materials. CDs are synthesized by solvothermal treatment of polypropylene carbonate (PPC) with ethylenediamine, and the quantum yield of CDs could increase from 30 to 86% by further adding trace of citric acid. The abundant functional groups on the surface of CDs allow CDs well incorporated into polymers to form CD-loaded polystyrene (PS) microspheres, which are employed to construct fluorescent supraballs via triphase microfluidic technique and used as “inks” for uniform fluorescent patterns. Interestingly, the resultant CDs show good flame retardancy for highly flammable polymeric foams and fibers. The CDs surpass previously reported flame-retardant additives, to show excellent combustion resistance that the addition of 20 wt% CDs causes 75% decrease in the peak of heat release rate (P-HRR) for polyurethane (PU) foams. Significantly, a molecular dynamics simulation process for PU/CDs combustion is constructed. This work may spur the preparation and application of high-performance carbon-based nanomaterials.

To meet the increasing energy demand, the research and development of efficient and clean fuel cells and metal-air batteries are of great significance. Under these circumstances, these hierarchically porous carbon nanomaterials obtained by pyrolysis of coordination polymers are regarded as excellent oxygen reduction catalysts and are expected to be used as air cathode materials. Herein, a type of 2-dimensional structure of InOF-26 has been thermally converted into ultrathin graphitized nitrogen-doped carbon nanosheets, denoted as NG-CNS. During the carbonization, the addition of ferric chloride assists in breaking the intermolecular forces between crystal structures, which is further conducive to the formation of carbon nanosheets with an improved graphitization degree. Meanwhile, the subsequent ammonia impregnation together with secondary calcination can readjust the coordination environment of nitrogen species in the carbonaceous matrix. The obtained product of NG-CNS exhibits excellent ORR performance with a high half-wave potential of 0.80 V, a large diffusion-limited current density of 6.00 mA cm−2, a small Tafel slope of 57.3 mV dec−1, to show unexpected practicability in Zn-air battery and Al-air battery. The relatively simple synthetic procedure, low cost, high repeatability, and satisfactory electrochemical performance of NG-CNS will provide a direction for the facile preparation of coordination polymer-derived carbon nanomaterials in energy storage and conversion applications.

Regulation of chemical composition and nanostructure, such as the introduction of dopant into two-dimensional nanomaterials, is a general and valid strategy for the efficient electrocatalyst design. In this work, Co4S3/Co9S8 nanosheets, with an ultrathin layer structure, were successfully synthesized via an efficient solvothermal process combined with ultrasonic exfoliation. Different metal ions (M = Fe3+, Cr3+, Mn2+ and Ni2+) were then doped by a simple cation exchange method and the effects of different dopants on the OER activities of Co4S3/Co9S8 NS were further investigated in alkaline media. The corresponding results implied that M-doped Co4S3/Co9S8 NS (M = Fe3+, Cr3+, Mn2+ and Ni2+) exhibited different electrocatalytic properties. Evidenced by XPS spectra, the different OER activities were mainly aroused by the redistribution of charge at the interface due to an electronic interaction between the doped metal ions and Co4S3/Co9S8 NS.

As a biologically active macromolecule, deoxyribonucleic acid (DNA) has the advantages of sequence programmability and structure controllability and can accurately transmit sequence information to specific biological functions. Facing the complex internal microenvironment and heterogeneity in tumor treatment, the construction and applications of DNA-based nanomaterials have become a focus point of research. In particular, the hybridization of DNA molecules with other materials endows DNA-based nanomaterials with multiple functions such as targeting, stimulus responsiveness and regulations of biological activities, making DNA nanostructures great potential in the treatment of major human diseases. In this review, the construction and characteristics of DNA-based nanomaterials are introduced. Then, the functions and applications of DNA-based nanomaterials in the delivery of chemotherapy drugs and gene drugs, stimulus-responsive release and regulation of cell homeostasis are reviewed. Finally, the future development and challenges of DNA-based nanomaterials are prospected. We envision that DNA-based nanomaterials can enrich the nanomaterial system by rational design and synthesis and address the growing demands on biological and biomedical applications in the real world.

Nanoparticles serve various purposes in the hydrocarbon industry which are utilized to improve the volume of oil and gas production. Nanomaterials are used in petroleum applications as nanoparticles, nanosensors, nanocomposites, coated nanoparticles, nanofluids etc. Thus, the application of nanotechnology in the enhanced oil recovery (EOR) method helps to extract the trapped oil present beneath the surface. Some nano ultra-fine particles are cost-effective and eco-friendly. The injected fluid interacts with the rock/oil system to create a favourable environment for oil recovery. This study focuses on a review of the different types of nanoparticles and nanomaterials used in petroleum applications. This paper aims to study the classification and characterization of nanoparticles. This also includes the physiochemical and mechanical properties of nanomaterials. The study discusses the applications of nanoparticles in chemical, miscible, thermal and microbial floodings. It mainly focuses on various mechanisms involved by adding nanoparticles such as wettability alteration, IFT reduction, rheology improvement, mobility control etc. This research also addresses new green nanomaterials and nanocomposites, which includes injecting specialized green chemicals (surfactants, alcohols, and polymers) that successfully displace oil. The IFT between the displacing fluid and the oil is reduced due to phase-behaviour properties.

Carbon dots (CDots), a class of environmentally friendly carbon-based luminescent nanomaterial, have been applied in a wide variety of fields, including bioimaging and light-emitting diodes (LEDs). Prior to these applications, however, CDots usually require modifications because some of its limitations (e.g., the aggregation-induced luminescence quenching) make it difficult to apply in solid state. In order to realize CDots-based multiple applications simultaneously, this paper examines how CDots with a strong greenish-yellow fluorescence in both dispersed and aggregated states are prepared by microwave-assisted heating salicylic acid and thiourea. Based on control testing and the analysis of density functional theory calculations, S element from thiourea is doped into CDots and proves to be critical in governing the photoluminescence (PL) emission color. Featured with excellent biocompatibility and photostability, the dispersed CDots with photoluminescence quantum yields (32%) are able to function as a biological imaging reagent in vitro and in vivo without any side effect. Furthermore, the aggregated CDots also exhibit high photoluminescence quantum yields (26%) and remarkable resistance to organic solvent. These advantages will ensure that S-doped CDots can be applied as a color conversion layer so that white LEDs with different Commission International de L’Eclariage coordinates and tunable color temperature can be fabricated.

Clean and sustainable energy is of one prime interest to current water production demands. Producing unpolluted drinking water and sustainable energy is the next big challenge to overcome. Solar steam generation has great future potentials for mankind. The need to overcome limitations of solar steam generation is in recent penchants. A highly efficient black photo-convertor nanomaterial is synthesized and functionalized to achieve 87% efficiency under one Sun (1kW.m-2) illumination. The black tin oxide (bSnO) nanomaterial was synthesized using electrocatalytic reduction approach, resulting a robust photo-convertor nanomaterial. To enhance the capabilities of water evaporation, polymerization was performed using PANI (polyaniline), and PPy (polypyrrole) referred to as bSnO@PANI and bSnO@PPy, respectively. Various physical factors as narrow bandgap, surface water ratios and localized heating are found remarkable to enhance overall efficiency. The bSnO@PANI was assessed to be at highest elevated temperature by acquiring nearly ∼82 °C in close to 100 seconds under one sun irradiance and nearly ∼56 °C when in contact with water body. Thus, final water evaporating rate recorded to be 2.04 kg.m-2 h-1 and 1.74 kg.m-2 h-1 for water and seawater, respectively. Producing drinking water from Dyed and sea-water are reported after solar evaporation. Achieving enormous evaporation rate can further be explored for green energy generation.

To develop special structure nanomaterials from nature with large specific surface areas and conduct appropriate doping may be effective ways to improve the performance of carbon-basing energy storage devices and mobile power supplies. Pure Gram-positive bacteria carbon material with dense microporous structure and properly self O, N-doping was developed towards highly performance supercapacitors for the first time. The structural characterization and electrochemial survey show that carbon derived from Gram-positive bacteria can bring unexpected material properties for its layered and nitrogen, oxygen containing peptidoglycan cell wall structure. Specifically, bifidobacterium yogurt starter powder as a representative of Gram-positive bacteria was employed and pre-carbonized at 450 °C, then re-carbonized at 700, 800 and 900 °C with KOH activated, respectively. The as-prepared Gram-positive bacteria carbons (GpBCs) have inherited the bacteria's cell wall structure to some extent, which makes the specific surface area as high as 2877 m2/g. When the mess ratio of the precursor to KOH was 1: 2 and re-carbonized at 800 °C, the sample named GpBC-800-2 exhibited a medium specific surface area (2436 m2/g), and possessed proper oxygen(11.20%) and nitrogen(0.56%) doping. For further electrochemial measurement, GpBC-800-2 delivered a specific capacitance of 220 F/g and a 94.5% retention after 10000 cycles in 6 M KOH at the current density of 1 A/g in three-electrode system. For further assessment on symmetry devices, 30 F/g specific capacitance was obtained and 97.8% retention after 10000 cycles were achieved in 6 M KOH at the current density of 1 A/g for symmetry devices. The constructed devices presented an energy density of 4.2 Wh/kg at the power density of 0.5 kW/kg, and still remained 3.19 Wh/kg at the power density of 5 kW/kg. Results of this work have given a first glance for pure Garm-positive bacteria carbon materials in supercapacitor application.

Colorimetric biosensors, based on enzyme-like nanomaterials, have come into the spotlight in virtue of their visual detection. Herein, a daisy-like zeolitic imidazolate framework-67/reduced grapheme oxide (ZIF-67/rGO) nanozyme with unique 3D hierarchical structures has been designed to realize visual detection of hydrogen peroxide (H2O2) that is recognized as a strong oxidizing agent or reactive oxygen species associated with oxidative stress in biological systems. The daisy-like ZIF-67/rGO is prepared by a facile one-step liquid-phase method conducted under room temperature. The successful introduction of rGO endows the daisy-like ZIF-67/rGO nanozyme with abundant porous structure, high specific surface area, and good charge transfer capability, which significantly accelerates the adsorbability and recognition towards the substrates and the oxidation rate of TMB-H2O2 reaction, and thus improving the nanozyme activity observably. It is conductive to nanozyme-modulated H2O2 determination. The established colorimetric biosensor platform based on ZIF-67/rGO nanozyme exhibits remarkable sensitivity and high specificity for the application in visual detection of H2O2. The detection limit of ZIF-67/rGO-based biosensor platform is as low as 3.81 μM, which is nearly 8 times lower than that of ZIF-67-based biosensor platform. Moreover, its potential applicability as an ideal platform for colorimetric biosensors is demonstrated by testing the concentration of H2O2 in milk samples, which sheds light on the promising application of the proposed biosensing system in point-of-care detection.

Enhancing the interfacial dispersion and suspension stability is crucial for magnesium hydroxide (Mg(OH)2) nanomaterials in the long-term deacidification of paper-based cultural relics. However, because of the low specific surface area and the poor solvent compatibility of as-prepared large-sized Mg(OH)2, it often tends to agglomerate and settle down during the usage and storage, that is harmful for paper protection due to its unevenly deacidification and nonuniformly distribution on paper cellulose. Herein, we propose a feasible preparation of colloidal Mg(OH)2 ultrathin nanoflakes with high dispersion stability via a simple one-step surfactant-assisted strategy. The surfactant acts as both a structure-direct agent to confine the growth of Mg(OH)2 with rich active sites and a surface modifier to enhance its solvent adaptability and dispersion stability, avoiding the common fussy procedure with additional steric stabilizer. Owing to the evenly interaction with free acid species therein and the uniformly distribution on the paper fiber as alkaline reserve, the as-obtained Mg(OH)2 presents the superior paper protection performance characterized by its safer pH of 7.29 for the original aged paper (pH = 5.03) and the excellent long-term anti-acidification effect with competitive pH of 5.47 after accelerated-aging at 105 °C for 5 months. Furthermore, Mg(OH)2 nanoflakes with surfactant-modified structure also endue them as an improved flame retardant for multifunctional paper protection. The protection with Mg(OH)2 has little effect on the paper surface properties and cellulose crystallinity, in line with the principle of least intervention. This work will put forward a feasible way toward colloidal Mg(OH)2 nanoflakes with excellent paper protection performance, shedding light on the development of emerging protection materials for paper-based cultural relics.

In recent years, phase change material emulsions (PCMEs) with enhanced energy storage capacities and good flow characteristics have drawn significant attention. However, due to the thermodynamically unstable nature and tiny particle confinement, the nanomaterial modification strategies at PCM/water interface to improve stabilities and reduce supercooling of nano-sized PCMEs (NPCMEs) are very limited and challenging. Herein, we report a facile strategy for constructing MXene-decorated NPCME with good stability, little supercooling, and high thermal conductivity by self-assembly of MXene nanosheets at PCM/water interface. The concentrations of MXene have great influences on the average droplet diameters, stabilities, and thermophysical properties of the NPCMEs. The results show that the PCMs have been well dispersed into the water in the form of quasi-spherical droplets, with average droplet diameters of 242–805 nm. The thermal conductivity of 10 wt% n-tetradecane/water NPCME containing 9 mg ml-1 MXene is 0.693 W m-1·K-1, achieving an enhancement by 15.5%, as compared to that of water. Besides, the MXene-decorated paraffin/water NPCMEs exhibit little supercooling and enhanced heat storage capacities. More importantly, this facile self-assembly strategy opens a new platform for preparing high-performance NPCMEs, which can be used as novel heat transfer fluids for thermal energy storage systems.