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Metal–nitrogen–carbon materials (Fe–N/C) have been extensively studied as one of the most excellent electrocatalysts with good catalytic activities and cheap price towards the oxygen reduction reaction (ORR). The rational design of metal–organic framework (MOF) derived carbon materials with rapid mass transport ability and good stability is a great challenge to achieve. Herein, intensive research of Fe–N/C catalysts prepared from assembling MOFs with cheap iron phthalocyanine (FePc) for the ORR is innovatively carried out. A series of Fe–N/C nano-architectures are simply synthesized by a convenient assembling method under different temperatures (800 to 1000 °C). The assembly method at high temperatures tunes the number of FeNx active sites and intensifies the exposure of interior active sites. The highly dispersing Fe20–N/C electrocatalyst treated at 900 °C exhibits remarkable stability and excellent ORR activities with a half-wave potential of 0.866 V (vs. RHE) in alkaline solution, which is higher than that of commercial Pt/C (0.838 V vs. RHE) under the same test conditions. X-ray photoelectron spectroscopy results illustrate that incorporated MOFs interact with the active centre of FePc, tend to enhance the electron transition and to promote the kinetics of the ORR. Overall, highly dispersed Fe–N/C MOF-based materials are excellent non-precious metal electrocatalysts for energy and environmental applications.

Polyaluminum chloride (PAC) is an inorganic polymer material that has the advantages of a simple preparation process and special electronic structure. It is considered to be the most efficient and widely used flocculation material for water treatment. In this work, PAC has been used as a Lewis acid catalyst in interdisciplinary fields because of its polynuclear Al-O cation structure. Further, its catalytic mechanism in green organic synthesis has been studied in detail by using the multicomponent Biginelli reaction as the probe. The effect of solvent on the self-assembly and aggregation process of PAC materials was investigated using optical microscopy, UV-Vis spectrophotometry, particle size analysis, XPS, IR, SEM and HR-TEM. The results show that the PAC materials have different morphological characteristics in different solvents. The Al-O-Al cations were transformed in the ethanol solvent to form new multi-nuclear cation aggregates Al

Due to its high strength, toughness, corrosion resistance and wear resistance, long chain polyamide (LCPA) has attracted broad interest. Nevertheless, its wide application in industrial fields is still being restricted because the starting material acquisition step involving diacid and diamine remains a major obstacle. Herein, we circumvent this obstacle by developing a novel polymer with similar properties by a green and efficient copolymerization process of carbon dioxide (CO2)-based dicarbamate with diamide diol under vacuum conditions, named poly(urethane-co-amide) (PUA). The semi-crystalline PUAs with high number-weight-average molecular weights (Mn, up to 41.3 kDa) were readily obtained, and these new polymers show high thermal stability (above 300 °C). Thanks to its unique chain structure, the amide, urethane and urea groups can endow the polymer with a high density cross-linking network via hydrogen bonds and high crystallinity that can result in high strength, up to 54.0 MPa. The dynamic thermomechanical analysis (DMA) results suggest that the phase separation exists within the new polymers, endowing the PUAs with a toughness higher than that of long chain polyamides. Consequently, this work not only develops a useful new polymer like commercial polyamides with high performance as a long chain polyamide candidate, but also provides a new way of utilizating CO2.

Fluorescent probes have been demonstrated to be promising candidates as biomarkers and biological carriers. Our study focuses on the development of a novel amphiphilic fluorescent probe with good photostability, high water solubility, excellent specificity and promising loading capability for tumor diagnosis and treatment. At first, BODIPY dye and O-carboxymethyl chitosan were prepared via a chemical reaction. Then, the prepared BODIPY dye and cRGD were bonded to O-carboxymethyl chitosan successively via an acylation reaction. Finally, we obtained the desired amphiphilic fluorescent probe: BODIPY–O-CMC–cRGD, which was based on the fluorescence resonance energy transfer (FRET) principle for selective visualization of tumors in vitro. Through a series of experiments, we found that this fluorescent probe possessed better fluorescence characteristics and tumor targeting properties. Simultaneously, by self-assembly, the amphiphilic probe encapsulated the other flexible structure of BODIPY2 and the rigid structure of porphyrin, which formed distinct nanoparticles with different particle sizes. Hence, we could observe different phagocytosis processes of the two nanoparticles in the tumor cells via the fluorescence of dyes by confocal laser scanning microscopy. Therefore, the results suggest that the fluorescent probe has advantages in tumor detection, and the constructed tumor-specific nanoparticles show high clinical potential to be utilized not only in visual and precise diagnosis but also in excellent drug delivery for tumor treatment. Henceforth, we will prepare new targeted and visualized pharmaceuticals by replacing BODIPY2 and porphyrin with antineoplastic drugs for future tumor treatment.

A novel fluorescent probe was constructed by the self-assembly of monosubstituted BODIPY and a novel targeted hydrophobin named hereafter as HFBI-RGD. Optical measurements and theoretical calculations confirmed that the spectral properties of the probe were greatly influenced by the BODIPY structure, the appropriate volume of BODIPY and the cavity of HFBI-RGD. The experiments in vivo and ex vivo demonstrated that the probe had excellent ability for tumor labelling.

In this paper, we report a novel organic fluorescent nanoparticle based on exciplexes for cell imaging. Through a reprecipitation method, we used a combination of 1,1-bis((di-4-tolylamino)phenyl)cyclohexane (TAPC) and 2,7-bis(diphenylphosphoryl)-9,9′-spirobi[fluorene] (SPPO13) to form nanoparticles. In the aggregated structures, TAPC and SPPO13 were forced into proximity that led to the corresponding exciplex formation. A red-shifted fluorescence emission with considerably longer fluorescence lifetimes ascribed to exciplex emission can be achieved. Along with the good stability and low cytotoxicity of organic nanoparticles, the prepared TAPC/SPPO13 exciplex nanoparticles were successfully applied in live cell imaging. These properties make TAPC/SPPO13 exciplex nanoparticles good candidates for cellular labeling and imaging materials.

Graphene-based multifunctional composites were prepared by encapsulating of magnetic ZnFe2O4@chitosan (ZnFe2O4@CS) particles into graphene oxide (GO) layers. The obtained ZnFe2O4@CS/GO were characterized using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Adsorption of basic fuchsin (BF) onto the ZnFe2O4@CS/GO was investigated using pH, adsorption time, initial BF concentration and temperature. Kinetic data and adsorption isotherms were better fitted by a pseudo-second-order kinetic model and Langmuir isotherm model, respectively. The values of activation parameters such as free energy (ΔG, −14.02 to −16.56 kJ mol−1), enthalpy (ΔH, 23.27 kJ mol−1) and entropy (ΔS, 127.75 J mol−1 K−1) were calculated, suggesting that the adsorption was a spontaneous, favorable and endothermic process in nature. The results demonstrated that the ZnFe2O4@CS/GO composites are potentially suitable materials for the removal of organic dyes from large volumes of wastewater.

Parallel and vertical interfaces in vertically and parallelly aligned nanocomposite thin films have been shown to be an effective method to manipulate functionalities. However, tuning the physical properties by modulating the microstructure of the self-assembled nanocomposite films and understanding the physical properties underlying the manipulation is still a challenge. In this work, BaTiO3:NiO (BTO:NiO) nanocomposite films with nanomultilayer, nanocolumnar and nanogranular structures have been prepared on Nb:SrTiO3 (Nb:STO) substrates by a pulsed laser deposition (PLD) method. These films have been used as a model system to investigate the relationship between the microstructure and the ferroelectric properties. The polarization, dielectricity and leakage can be separately modulated by tuning the microstructures. The experimental results show that the remanent polarization of the nanocomposite films is much higher than that of the pure BTO films. By precisely modulating the microstructure, a significantly enhanced polarization (>70% higher than pure BTO for the nanomultilayer structure) and dielectricity (>60% and >240% higher than pure BTO for the nanomultilayer and nanocolumnar structure, respectively) are realized in these films. These results demonstrate that tunable ferroelectric properties can be realized by controlling the microstructures in the epitaxial BTO:NiO nanocomposite thin films, which will be expected to be applied in the devices such as supercapacitors, solar cells and non-volatile memory applications.

A cellulose sulfonate catalyst (HS-cellulose sulfonate) with high stability, excellent catalytic activity and high acidity value (about 1.55 mmol g−1) was successfully prepared by SO3 gas phase sulfonation. The basic morphology and nanostructure of the catalyst were determined by HRTEM, XRD, IR, TG, etc. In addition, the catalyst was applied to the catalytic reaction of a dihydroquinazolinone derivative and a xanthene compound, and very valuable results were obtained. The development and preparation of cellulose sulfonate catalysts provide a good approach for the development and application of cellulose, and also an important application of green organic catalytic synthesis methodology.

Due to its high strength, toughness, corrosion resistance and wear resistance, long chain polyamide (LCPA) has attracted broad interest. Nevertheless, its wide application in industrial fields is still being restricted because the starting material acquisition step involving diacid and diamine remains a major obstacle. Herein, we circumvent this obstacle by developing a novel polymer with similar properties by a green and efficient copolymerization process of carbon dioxide (CO

Applications of europium-doped NaYF4 (NaYF4:Eu3+) nanoparticles in biomedical fields will inevitably increase their exposure to humans, therefore, the assessment of toxicities must be taken into consideration. It was reported that NaYF4:Eu3+ nanoparticles could accumulate in the bone. However, the potential effect of NaYF4:Eu3+ nanoparticles on bone marrow stromal cells (BMSCs) has not been reported. In this study, NaYF4:Eu3+ particles with diameters of 50 and 200 nm (NY50 and NY200) were prepared and characterized by scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, photoluminescence excitation and emission spectra, and dynamic light scattering. The cytotoxicity of NaYF4:Eu3+ particles on BMSCs and the associated mechanisms were further studied. The results indicated that NaYF4:Eu3+ particles could be uptaken into BMSCs and primarily localized in the lysosome. NaYF4:Eu3+ particles effectively inhibited the viability of BMSCs in a size-dependent manner at 24 and 48 h. After cells were treated with 20 μg mL−1 of NY50 and NY200 for 24 h, NaYF4:Eu3+ particles could trigger cell necrosis in a size-dependent manner. The percentage of necrotic BMSCs (PI+/Annexin V−) increased to 15.93 and 14.73%. Necrosis was further verified by increased lactate dehydrogenase leakage. Meanwhile, both NY50 and NY200 induced an increased cell population in the S and G2/M phases. The following mechanism is involved in NaYF4:Eu3+ particle-induced BMSCs necrosis: the NaYF4:Eu3+ particles lead to lysosomal rupture by lysosomal swelling, permeabilization of lysosomal membranes, and increased cathepsins B and D. In addition, NaYF4:Eu3+ particle-induced BMSCs necrosis is also directly caused by the overproduction of ROS through injury to the mitochondria. This study provides novel evidence to elucidate the toxicity mechanisms for bone metabolism and may be beneficial to more rational applications of these nanomaterials in the future.

Dye-sensitized solar cells (DSSCs) fabricated with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) composite gel electrolytes containing variable amounts of modified kaolin were studied in this work. The kaolin was modified with silane coupling agent γ-aminopropyltriethoxysilane (KH550), and the modified kaolin (M-KL) was characterized by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The results of X-ray diffraction (XRD) and differential scanning calorimetry (DSC) indicated that the crystallinity of polymer membranes decreased with the addition of M-KL nanoparticles. The ionic conductivity and diffusion coefficient (I3−) of polymer gel electrolytes (PGEs) reached optimum values of 9.452 × 10−3 S cm−1 and 10.37 × 10−6 cm2 s−1 for 3 wt% M-KL, respectively, which contributed to higher short-circuit current density (Jsc) and photoelectric conversion efficiency (η) of the corresponding DSSCs. The optimum level of η reached 7.48% under the illumination of 100 mW cm−2, an increase of 16.3% compared with the DSSC without M-KL.

The combination of a metal with a semiconductor is a promising route to improve the solar-to-chemical conversion efficiency of photocatalysts. In this article, ultrathin Pd nanosheets are integrated with semiconductor TiO2 nanosheets for photocatalytic hydrogen evolution, which acts as a cocatalyst and plasmonic agent in ultraviolet and visible-near-infrared spectral regions, respectively. Owing to the unique two-dimensional (2D) nanostructure, the Pd nanosheet cocatalyst realizes the large TiO2–Pd interfacial area for electron transfer as well as a large Pd exposed area for reduction reactions, while the plasmonic Pd nanosheets offer strong vis-NIR light absorption for “hot” electron production as well as a large interfacial area for “hot” electron injection. As a result, the Pd nanosheets achieve improved photocatalytic activity in comparison with three-dimensional Pd nanotetrahedrons under both light irradiations. This work underlines the importance in choosing a suitable shape of metal in the surface and interface design of semiconductor–metal hybrid photocatalysts as well as the advantages of 2D metal nanostructures in realizing high photocatalytic performance.

The competitive oxidation reaction mechanism of methanol on the Ru(0001) surface has been investigated by periodic density functional theory (DFT). Stable adsorption configurations, elementary reaction energies and barriers, the potential energy surface (PES), and the electrochemical potential analysis were elucidated. The results showed that O–H bond activation was more competitive than C–H and C–O bond activation during the initial methanol oxidation. Competitive pathways occurred for CH3OH oxidation to CH2O via CH3OH → CH3O → CH2O versus CH3OH → CH2OH → CH2O, further to COOH via the CO pathway CH2O → CHO → CO → COOH versus the non-CO pathway CH2O → CH2OOH → CHOOH → COOH, and finally oxidation to CO2. Taking PES and the electrochemical potential analysis into account, CH3OH → CH2OH → CH2O → CH2OOH → CHOOH → COOH → CO2 appeared to be the preferred oxidation pathway. The OH group could inhibit CO formation by directly reacting with CH2O to yield CH2OOH but could not efficiently remove the CO that had already been produced by the reactions.

The crystal configuration, electronic structure, charge-carrier transport, and optical properties of Ge-based MAGeX3 perovskites (MA = CH3NH3+; X = Cl−, Br−, and I−) and AGeI3 (A = Cs+, MA, FA (HC(NH2)2+), MO (CH3C(NH2)2+), and GA (C(NH2)3+)) were investigated using first-principles theory. The results showed that the increase in Ge–X bonds (from Cl− to I−) in MAGeX3 increased the volumes, weakened the covalent coupling of Ge–X, lowered the bandgaps, reduced the electron and hole effective masses, and red shifted the absorption spectra. Different A cations in the AGeI3 systems altered the package of perovskite crystals and thus significantly influenced the electronic and optical properties of those perovskites. Electronic property analyses revealed that the valence band maxima (VBM) of AGeI3 perovskites were mainly contributed by the I 5p and Ge 4s orbitals, whereas the conduction band minima (CBM) were dominated by Ge 4p orbitals. In AGeI3 perovskites, the bandgap increased and the absorption spectrum blue shifted in the sequence of Cs+ → MA → FA → MO → GA. Our results highlighted the effects of A and X on the photoelectronic properties of Ge-based perovskites.

Herein, we present a simple and rapid method to synthesize porous silicon/carbon microtube composites (PoSi/CMTs) by adopting a unique configuration of acid etching solution. The CMTs can act as both conductive agent and buffer for Si volume change during the charge and discharge process. The highly reversible capacity and excellent rate capability can be ascribed to the structure, where porous silicon powders are wrapped by a network of interwoven carbon microtubes. The composites show specific capacities of more than 1712 mA h g−1 at a current density of 100 mA g−1, 1566 mA h g−1 at 200 mA g−1, 1407 mA h g−1 at 400 mA g−1, 1177 mA h g−1 at 800 mA g−1, 1107 mA h g−1 at 1000 mA g−1, 798 mA hg−1 at 2000 mA g−1, and 581 mA h g−1 at 3000 mA g−1 and maintain a value of 1127 mA h g−1 after 100 cycles at a current density of 200 mA g−1. Electrochemical impedance spectroscopy (EIS) measurements prove that charge transfer resistance of PoSi/CMT composites is smaller than that of pure PoSi. In this study, we propose a quick, economical and feasible method to prepare silicon-based anode materials for lithium-ion batteries.

Fluorescent probes have been demonstrated to be promising candidates as biomarkers and biological carriers. Our study focuses on the development of a novel amphiphilic fluorescent probe with good photostability, high water solubility, excellent specificity and promising loading capability for tumor diagnosis and treatment. At first, BODIPY dye and

In order to decrease the brittle–toughness transition temperature and increase the mechanical strength of poly(propylene carbonate) (PPC), a series of multiblock copolymers of poly(propylene carbonate)-multiblock-poly(butylene succinate) (PPC-mb-PBS) are designed and synthesized. 1H-NMR, DOSY and GPC results demonstrate the successful synthesis of PPC-mb-PBSs with designed multiblock sequence. The thermal, crystalline and mechanical properties of these PPC-mb-PBSs are evaluated by DSC, TGA, POM, tensile and tearing testing. Experiment results demonstrate that crystallinity, thermal and mechanical properties of PPC-mb-PBSs can be readily modulated by changing the composition and block length of PPC and PBS moieties. It is found that all the prepared PPC-mb-PBSs are semi-crystalline polymers with a melting temperature at 93–109 °C and a Tg at around −40 °C. Both crystallization rate and crystallinity of the multiblock copolymers increase with increasing both PBS content and PBS block length. As a consequent, the tensile strength increases with increasing PBS/PPC block ratios at room and lower temperatures. In conclusion, the amorphous PBS phase in the block copolymers acts as soft segment, endowing PPC-mb-PBS copolymers with much better flexibility than PPC at low temperature of 273 K when PPC segments are frozen.

A MePPh2-catalyzed [4 + 2] cycloaddition reaction of unsaturated pyrazolones with allenoates was described. The reaction affords the spiropyrazolone derivatives in moderate to excellent yields with moderate to good diastereoselectivities under mild conditions. Using thiourea-based bifunctional phosphines as chiral catalysts, an asymmetric variant of this [4 + 2] cycloaddition reaction has been achieved, giving chiral spiropyrazolone derivatives in moderate to excellent yields with moderate to excellent diastereoselectivities and excellent enantioselectivities (89–95% ee).

A photoluminescent biosensor was developed for the detection of microRNA (miRNA) combined signal amplification of long-range self-assembled DNA cascades with upconversion nanoparticles. The sensor exhibited superior sensitivity with a detection limit of microRNA-21 (miR-21) as low as 1 fM, which may represent the potential of being used in miRNA analysis and clinical diagnosis of breast cancer.

First-principle calculations were performed to explore the initial reduction of CO2 on perfect and O-defective CeO2 (111) surfaces via direct dissociation and hydrogenation, to elucidate the product selectivity towards CO, COOH, or HCOO. The results showed that CO2 prefers a bent configuration with the C atom of CO2 occupying the oxygen vacancy site. Reductive hydrogenation CO2 + H → COOH* was more competitive than CO2 + H → HCOO* on both perfect and O-defective CeO2 (111) surfaces. Comparatively, CO2 hydrogenation towards COOH was slightly more favorable on the perfect surface, whereas reductive dissociation of CO2 was predominant on the O-defective CeO2 (111) surface. Electronic localization function, charge density difference, and density of states were utilized to analyze the effect of charge accumulation and redistribution on the adsorption and reductive dissociation of CO2 caused by the presence of O vacancies. The results of this study provided detailed insight into the initial reduction mechanisms of CO2 towards different products on perfect and O-defective CeO2 (111) surfaces.

To better understand the potential impact of Eu3+ doped gadolinium oxide nanotubes (Gd2O3:Eu3+ nanotubes) on human health, we investigated their biodistribution, subacute toxicity, and hepatic injury in mice under different dosages (4.0, 40.0, and 400.0 mg kg−1). The results showed that the gadolinium element was mainly accumulated in the spleen, liver, lung, kidney, and bone. The relative organ weight of spleen in the middle-dose group and high-dose group was significant higher than that of the control group. However, the relative organ weight of liver and kidney had no obvious difference from the control group. Besides, the change of toxicity on the hematological system was not noticeable under the tested doses. The high-dose Gd2O3:Eu3+ nanotubes increased the alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) levels, but no significant difference was observed in the low-dose group and middle-dose group compared with the control group. These changes demonstrated that high-dose Gd2O3:Eu3+ nanotubes induced liver injury. Based on the changes of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), glutathione S-transferase (GST), reactive oxygen species (ROS), malondialdehyde (MDA), and protein carbonylation levels, it can be deduced that high-dose Gd2O3:Eu3+ nanotubes could induce liver injury by oxidative stress. Furthermore, the levels of inflammatory cytokines, such as tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-8 (IL-8), increased upon high-dose Gd2O3:Eu3+ nanotube treatment. The results may benefit the applications of Gd2O3:Eu3+ nanotubes.

In this work, bimetallic Au–Pt alloyed nanowire networks (AuPt NNs) were facilely synthesized by a simple and rapid one-pot wet-chemical method on a large-scale, using N-methylimidazole as a structure-directing agent and a weak stabilizing agent. The surface of AuPt NNs was clean owing to the easy removal of the adsorbed N-methylimidazole. The control experiments demonstrated that the morphologies of AuPt NNs were strongly correlated with the amount of N-methylimidazole and reaction temperature. The formation mechanism included the four-stage growth processes: rapid nucleation, selective adsorption, π–π induced assembly, and oriented attachment growth. The as-synthesized AuPt NNs exhibited enhanced electrocatalytic activity and improved stability for methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) as compared to commercial Pt black and individual Pt nanoparticles.

A facile hydrothermal strategy was designed for the preparation of alloyed PtNi nanosnowflakes supported on reduced graphene oxide (PtNi nanosnowflakes/RGO), with the assistance of N,N-dimethylformamide (DMF) as the solvent and reductant, and ethylenediamine as the surfactant and capping agent. The as-obtained nanocomposites were mainly characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, which showed enhanced catalytic activity and better stability over commercial Pt/C (10 wt%) in the catalytic reduction of p-nitrophenol to p-aminophenol.