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Herein, a solution-free dry strategy for the growth of self-assembled ordered tricopper phosphide (Cu3P) nanorod arrays is developed and the product is employed as a high-energy, stable positive electrode for a solid-state hybrid supercapacitor (HSC). The ordered Cu3P nanorod arrays grown on the copper foam deliver an excellent specific capacity of 664 mA h/g with an energy efficiency of 88% at 6 A/g and an ultra-long cycling stability over 15,000 continuous charge–discharge cycles. These electrochemical features are attributed to the ordered growth of the Cu3P nanorod arrays, which offers a large number of accessible electroactive sites, a reduced number of ion transfer paths, and reversible redox activity. The potential of the Cu3P nanorod arrays is further explored by engineering solid-state HSCs in which the nanorods are paired with an activated carbon-based negative electrode. The constructed cell is shown to convey a specific energy of 76.85 Wh/kg at a specific power of 1,125 W/kg and an 88% capacitance retention over 15,000 cycles. Moreover, the superior energy storing and delivery capacity of the cell is demonstrated by an energy efficiency of around 65%. The versatile solution-free dry strategies developed here pave the way towards engineering a range of electrode materials for next-generation energy storage systems.

In this study, a simple approach is established to fabricate NiCoSe4 nanorods grown onto carbon nanofiber (CNF) skeletons by combining electrospinning and a hydrothermal process. We achieved the rapid and ultrasensitive electrocatalytic sensing of tryptophan (Trp) in 0.1 M KOH by using intrinsically metallic NiCoSe4 anchored on CNFs as an alternative working electrode material. Benefiting from the large surface area due to rich defect active sites and the high electrocatalytic behavior of NiCoSe4 with CNF, the fabricated sensor exhibits a lower electron-transfer resistance of Rct 92 Ω with respect to the CNF–NiCo and CNFs electrodes. The results of voltammetric technique confirmed that the CNF–NiCoSe4-GCE showed higher anodic peak intensity and a lower anodic potential for Trp detection than CNFs-GCE and CNF–NiCo-GCE electrodes since the integration of sp2 carbon on the surface of the CNFs and bimetallic selenides improves the sensing performance. The amperometric I-t curve showed a linear response in the Trp concentration range of 5–95 nM and a detection limit of 0.68 nM at low potential of 0.4 V vs. Hg/HgO. The CNF–NiCoSe4-GCE was successfully utilized for the electrocatalytic monitoring of Trp from human serum, milk, and tomato juice samples with a recovery of 95.4–105.5%.

In this work, we fabricate porous cesium lead bromide nanofibers (CsPbBr3 NFs) via electrospinning and employ them in a sensor to effectively detect both gaseous and aqueous ammonia. The CsPbBr3 NFs are produced by first mixing cesium lead bromide nanocrystals (CsPbBr3 NCs) with polystyrene (PS), followed by solidifying the mixture into NFs using electrospinning. Porous NFs are modified using the volatile solvent toluene, which is volatilized during the electrospinning process. The applicability of the proposed CsPbBr3 NFs for use under various environmental conditions is verified by analyzing their stability in response to changes in temperature, moisture level and pH, which are critical drawbacks of CsPbBr3 NCs. Gaseous ammonia (9 mg L−1) in an N2 carrier is subsequently detected using the photoluminescence (PL) properties of the CsPbBr3 NFs. In addition, an ammonia concentration of 100.0 mg L−1 in an aqueous solution can be detected using the PL intensity. Therefore, we believe that the proposed CsPbBr3 NFs show significant promise for use in detection sensors to assess the extent of food decay, allowing customers to purchase fresh agricultural products more safely.

The beguiling world of functional polymers is dominated by thermoresponsive polymers with unique structural and molecular attributes. Limited work has been reported on the protein-induced conformat...

Pyrolysis fuel oil (PFO) is used for the manufacturing of high-purity pitch for carbon precursor due to its high carbon content, high aromaticity, and low heterogeneous element and impurity content. Pitch is commonly classified with its softening point, which is most considerable physical property affecting to various characteristics of the carbon materials based on pitch, such as electrical and thermal conductivity, mechanical strength, and pore property. Hence, the softening point should be controlled to apply pitch to produce various carbon materials for different applications. Previous studies introduce reforming process under high pressure and two step heat treatment for the synthesis of pitch with high softening point from PFO. These methods lead to a high process cost; therefore, it is necessary to develop a process to synthesize the pitch with high softening point by using energy effective process at a low temperature. In this study, waste polyethylene terephthalate (PET) was added to control the softening point of PFO-based pitch. The pitch synthesized by the heat treatment with the addition of PET showed the softening point higher than that of the pitch synthesized with only PFO. The softening point of PFO-based pitch synthesized at 420 °C was 138.3 °C, while that of the pitch synthesized by adding PET under the same process conditions was 342.8 °C. It is proposed that the effect of the PET addition on the increase in the softening point was due to the radicals generated from thermal degradation of PET. The radicals from PET react with the PFO molecules to promote the polymerization and finally increase the molecular weight and softening point of the pitch. In addition, activated carbon was prepared by using the pitch synthesized by adding PET, and the results showed that the specific surface area of the activated carbon increased by the addition of PET. It is expected that the pitch synthesis method with PET addition significantly contributes to the manufacture of pitch and activated carbon.

Human curiosity about the mysteries in outer space has driven humans to organize space explorations. Space missions and polar region solicitations require the use of new energy storage technologies with excellent tolerance to extremely low temperatures and the capability to operate efficiently for an extended time. In this context, it is urgent to explore new approaches and concepts to address the critical challenges via mechanistic understanding of new electrochemical reactions and phenomena in diverse scenarios. This paper presents how electrode and electrolyte materials in supercapacitor (SC) cells operate at extremely low temperatures. The critical challenges related to engineering such SCs and the major breakthroughs that overcome these problems are presented. In addition, the effects of different electrolytes (e.g., aqueous, organic, and ionic liquids (ILs)) on the ion accessibility, interfacial charge transfer, and transport kinetics in SC cells under cold conditions are discussed. This review is expected to contribute to the development of high-performance SC cells that can function at severe temperatures by providing insight into the key challenges and guidelines that facilitate future work.

The construction of systematically designed heterostructures with different integrated functionalities in a well-oriented nanoarchitecture is an efficient strategy for attaining high-performance ph...

Due to their high capacity, nickel–cobalt-based cathode materials have attracted significant attention as potential components of hybrid solid-state supercapacitors (HSSCs). However, their poor cycling stability and low rate capability have impeded their implementation. In the present study, a single-step, binder-free potentiodynamic polarization approach is presented for the preparation of battery-type phosphorus-containing amorphous trimetal nickel–ruthenium–cobalt hydroxide (P@NRC-OH) nanofibers on Ni foam for use in high-energy, stable HSSCs. The phosphate dopant and the trimetal-rich electrode surface increase the intrinsic electron conductivity and redox activity and generate a large number of active defects. As a consequence, a P@NRC-OH electrode exhibited enhanced energy storage properties in terms of specific capacity (541.66 mA h g−1 at 3 mA cm−2), cycling durability (90.35% over 20 000 cycles), and rate capability (308.64 mA h g−1 at 20 mA cm−2). An assembled full-cell HSSC with P@NRC-OH nanofibers as the cathode material and porous activated carbon as the anode material produced a maximum specific energy of 90.02 W h kg−1 at a specific power of 1363 W kg−1 which remained as high as 37.87 W h kg−1 at a power density of 6818.18 W kg−1, with remarkable cycling stability over 15 000 charge–discharge cycles. The proposed approach thus represents a scalable and efficient strategy for the design of electrodes and devices with superior electrochemical performance.

A porous nanostructure and high mass loading are crucial for a pseudocapacitor to achieve a good electrochemical performance. Although pseudocapacitive materials, such as MnO2 and MoS2, with record capacitances close to their theoretical values have been realized, the achieved capacitances are possible only when the electrode mass loading is less than 1 mg cm−2. Increasing the mass loading affects the capacitance as electron conduction and ion diffusion become sluggish. Achieving fast ion and electron transport at high mass loadings through all active sites remains a challenge for high-mass-loading electrodes. In this study, 2D MnO2 nanosheets supported on carbon fibers (MnO2@CF) as well as MoS2@CF with high mass loadings (6.6 and 7.2 mg cm−2, respectively) were used in a high-energy pseudocapacitor. These hierarchical 2D nanosheets yielded outstanding areal capacitances of 1187 and 495 mF cm−2 at high current densities with excellent cycling stabilities. A pliable pseudocapacitive solid-state asymmetric supercapacitor was designed using MnO2@CF and MoS2@CF as the positive and negative electrodes, respectively, with a high mass loading of 14.2 mg cm−2. The assembled solid-state asymmetric cell had an energy density of 2.305 mWh cm−3 at a power density of 50 mW cm−3 and a capacitance retention of 92.25 % over 11 000 cycles and a very small diffusion resistance (1.72 Ω s−1/2). Thus, it is superior to most state-of-the-art reported pseudocapacitors. The rationally designed nanostructured electrodes with high mass loading are likely to open up new opportunities for the development of a supercapacitor device capable of supplying higher energy and power.

A graphene aerogel (GA) with a three-dimensional (3D) structure, ultra-lightweight nature, and high hydrophobicity was simply fabricated by the one-step pyrolysis of glucose and ammonium chloride. The as-synthesized GA exhibited a 3D interconnected microporous architecture with a high surface area of ∼2860 m

A new core-shell structured MnO2@Ni2P2O7 (NPO) nanohybrid with unique nano-design is engineered by simple solution process and utilized as promising positive electrode for solid-state hybrid supercapacitors (HSCs). Firstly, two-dimensional (2D) NPO micro-sheets are grown on the Ni foam where the ultrathin MnO2 nanoflakes are decorated on NPO micro-sheets to realise MnO2@NPO core-shell nanohybrid. The as-synthesized MnO2@NPO electrode delivers impressive electrochemical performances with specific capacity of 309 mA h/g with long-term cycling stability over the 12,000 charge-discharge cycles. A solid-state hybrid supercapacitor (HSC) is fabricated using MnO2@NPO and activated carbon (AC) as positive and negative electrodes with polymer-gel electrolyte. The assembled HSC offers an upgraded cell potential of 1.6 V with high specific energy of 66 Wh/kg at specific power of 640 W/kg. More importantly, the HSC delivers excellent cycling stability over the 10,000 cycles (∼93% of capacity retention) with good energy efficiency at all current densities.

Novel hybrid decontamination processes based on visible-light-responsive photocatalysts (VLPHS) have recently become a focus of environmental research. In this study, the sonophotocatalytic degradation of the antibiotic tetracycline (TC) using a binary rGO/CdWO4 composite under simulated visible-light irradiation was demonstrated for the first time. Structural characterization confirmed that flower-like CdWO4 particles with a wolframite phase structure were successfully immobilized on the surface of the graphene oxide (GO). Subsequently, reduced GO/CdWO4 (rGO/CdWO4) VLPHS were prepared via the facile photocatalytic reduction of GO/CdWO4. A Box-Behnken design based on response surface methodology (RSM) was employed to determine the maximum efficiency of sonophotocatalytic degradation by optimizing the process parameters (pH, initial TC concentration, treatment time, and catalyst dosage). The high determination coefficients (R2 = 0.9818 and adjusted-R2 = 0.9636) indicated that the experimental values fitted the proposed RSM model well. Compared with CdWO4, rGO/CdWO4 VLPHS exhibited significant photoelectrochemical (PEC) performance, superior sonophotocatalytic activity, and mineralization efficiency. The enhanced catalytic activity was mainly due to the larger optical adsorption range, greater photo-induced charge carrier transfer, and higher surface area. In addition, rGO/CdWO4 exhibited a catalytic activity that was 1.5 and 3 times higher than that of commercial nano–ZnO and –TiO2, respectively. The kinetic analysis indicated that the degradation rate of TC follows the Langmuir–Hinshelwood kinetic model. The possible photocatalytic mechanism behind the degradation of TC by rGO/CdWO4 was also tentatively proposed. This study provides a simple and scalable pathway to produce highly efficient rGO-based VLPHS for photocatalytic and PEC applications.

This work focus to alleviate the fouling in Membrane bioreactor (MBR) by integrating electrooxidation, adsorptive cake, bio-film carriers and ozonation referred as Integrated Moving Bed Bioreactor (IMBBR). The total organic carbon (TOC), Chemical Oxygen Demand (COD) and Total Dissolved Solids (TDS) removal were observed as above 95%, 95% and 70% at 300 kPa with the flux increase in 35%. The numerical model was developed which proved less fouling which was in agreement with Scanning electron microscopy (SEM) and Liquid Chromatography and Mass Spectroscopy (LCMS). This study showed less energy consumption without the problem of filamentous bulking.

Here we describe a tetrapod microneedle injector that produces multifunction encoded particles. The custom-built tetrapod-like needle injector consists of spatially oriented microneedles operated by micropump using programmed on and off sequences. For the purpose of this study to achieve various functions from one particle, each constituent contained in a multifunction encoded particle confirms the cesium adsorption of PB, the drug release behavior of DTPA, and rapid mixing of immiscible liquids due to magnetic actuation. We believe that the multi-functionalized particles may have synergistic multifunctional properties and push the boundaries of advanced biomaterials in biomedical engineering.

Gold-silver (AuAg) alloys, an important noble bimetallic system, have received significant attention due to their chemical stability and unique properties for use in catalysis, surface-enhanced Raman scattering (SERS) and biomedical applications. We report a chemical approach to reconstruct the morphology of AuAg spiky nanostars using additional metal ions, into nanostructures that exhibits enriched SERS-based chemical sensing. To achieve this, we developed a two-step reduction process involving the simultaneous reduction of gold and silver followed by a successive reduction process. First, AuAg nanostars were synthesized by reducing Au and Ag using a one-pot method. Secondly, Au and Ag ions were separately deposited on the as-prepared AuAg nanostars and reduced. Successive reduction of Ag onto the AuAg nanostar resulted in a layered core-shell nanostructure with minimal mixing of the two metals. The deposition of Au ions onto the AuAg nanostars yielded maximally mixed alloyed nanostructures. There was no significant change in the morphology of the spiky nanostars with the use of high or low Ag feed concentrations or low Au concentrations. However, a new star-like nanostructure was formed as a result of the successive reduction of Au ions at a high feed concentration. The properties evaluated by SERS studies reveals that the as-prepared maximally mixed random alloy outperforms the minimally mixed layered core-shell nanostructures.

We investigated the catalytic efficiency of alginate hydrogels used as a catalyst support. An alginate solution containing palladium and magnetic nanoparticles was dropped continuously through a tapered glass capillary using a syringe pump, and the generated alginate droplets were collected in an aqueous solution containing divalent cations. The prepared PdNPs/MNPs-embedded alginate particles were used as a catalyst, catalyst support, and magnetic stirrer for the reduction of 4-nitrophenol. The catalytic reactions were found to depend on the magnetic stirring of the alginate hydrogels. Furthermore, we examined the recyclability while changing the alginate concentration, divalent cation species, and incubation protocols.

In this work, a Prussian blue (PB)/graphene oxide (GO)/chitosan (CS) organic-inorganic composite was successfully synthesized and utilized as an adsorbent for the selective removal of cesium (Cs+) ions. Taking the advantage of synergistic effect GO, CS and PB nanoparticles, the PB/GO/CS composite exhibited maximum adsorption capacity of 48.35 mg g−1 for Cs+ ions. In the presence of competitive monovalent cations (K+ and Na+), PB/GO/CS showed excellent selectivity (86%) for Cs+ ions and had a 6-fold higher distribution coefficient (Kd) than GO/CS. This enhanced adsorption capacity with high selectivity of PB/GO/CS for Cs+ ions may have been attributed to (i) the presence of carboxylic, hydroxyl and amino functional groups on GO/CS matrix which strongly bind Cs+ ions through electrostatic attraction and chelation, and (ii) the trapping of Cs+ ions by the voids of the FCC-structured PB lattice whose size is equivalent to the hydration radius of Cs+ ions. Due to its low-cost, facile preparation, high adsorption capacity, and superior Cs+ ions selectivity, PB/GO/CS is a promising material for the selective removal of the Cs+ ions from the environment and for protecting ecosystems from the radiation hazards.

We report a one-pot seedless green method for the synthesis of gold-silver (AuAg) spiky branched nanostars, with gold (90%) being the major component. Here, the zwitterionic surfactant lauryl sulfobetaine (LSB) is employed in the synthesis of bimetallic nanostars. The concentration of LSB plays an important role in determining the shape of nano-objects. A minimum LSB concentration of 50 mM is required for the formation of spiky branched nanostars, the size of which is controlled by increasing the LSB concentration. Two distinct intense localized surface plasmon resonances in the near-infrared (NIR) and short-wavelength infrared ranges are observed. The molecular structure of LSB causes LSB molecules to assemble into spherical micelles that act as a soft template for the growth of the nano-objects. An analysis of the mechanisms behind the formation of the nanostars suggests that there is a rapid growth of spikes followed by the formation of a spherical core at the center. AuAg nanostars with evenly spaced spikes and low branching demonstrate great potential as efficient nanocatalysts, surface-enhanced Raman scattering-active substrates and for photothermal therapy, active in both the visible and NIR regions.

Over the past two decades, the radiosynthesis of metallic nanoclusters (MNCs) using γ-irradiation (γ-radiosynthesis) has presented a wealth of opportunities for the application of nanomaterials in areas such as medicine, energy, catalysis, and sensors. Unlike conventional methods, this technique provides fully reduced and highly stable MNCs that are free from by-products or impurities. γ-Radiosynthesis has thus proven to be a clean and green approach for bulk fabrication of MNCs with tunable particle sizes and morphologies. More recently, the in-situ decoration of MNCs on support materials using γ-irradiation has attracted much attention due to the synergistic effect between MNCs and the underlying support. In this review, we discuss the current state of research into the mechanisms underlying the γ-radiosynthesis of supported and unsupported mono- and bi-metallic nanoclusters and summarize the use of MNCs in catalysis, sensing, biomedicine, and energy applications.

Electrum, the AuAg bimetallic alloy, has been an important system since ancient times to the present day, as these alloys have bi-functional properties lacking from their constituent metallic elements. We report a simple synthesis of a novel AuAg@Ag core@shell nanostructure (NS), where a bimetallic AuAg alloy hollow nanocube (HNC) core was coated with a monometallic Ag shell. The AuAg hollow cubic NSs were synthesized through a direct, one-pot synthetic protocol using Tween 80 micelles, a non-ionic surfactant, as a soft-template. The core@shell NSs were prepared from Ag and ascorbate ions under alkaline conditions in the presence of AuAg HNC as the core. The atomic percent of Ag in the core-shell NS was varied by using different amounts of the feed Ag ions during the synthesis. Depending on the Ag nanoparticle coating, the localized surface plasmon resonance (LSPR) peak of the AuAg@Ag core-shell hollow cubic NS underwent significant blue-shifting and narrowing. The necessity for such a AuAg alloy core and Ag-shell NS was demonstrated via surface-enhanced Raman scattering (SERS) studies performed using 4-mercaptothiophenol (4-MPh) as a probe molecule. Moreover, the sensitivity of the AuAg@Ag core-shell NSs as effective SERS substrates was revealed via concentration-dependent SERS studies on 4-MPh (up to 1 aM). In this work, the importance of electronic ligand effects associated with charge transfer from the AuAg alloy core through the Ag shell to the probe molecule has been highlighted using the commonly studied 4-aminothiophenol.

Practical implementation of photocatalytic hydrogen production has been required for the invention of efficient visible light absorption and low cost photocatalyst materials. n-Type metal oxides can couple with p-type semiconductors to provide p–n heterojunctions. This is one of the possible strategies to simultaneously address the visible light absorption and charge separation issues. Hence, a noble metal free quaternary Cu2ZnSnS4 (CZTS) decorated CeO2 p–n heterojunction photocatalyst has been designed and confirmed by HRTEM, Raman and XPS analysis. The growth of CZTS on the surface of CeO2 has significantly enhanced the hydrogen production performance. The optimal amount of CZTS loaded on CeO2 achieved the highest hydrogen production efficiency of 2930 μmol h−1 g−1 under visible light illumination, which is 59 times higher than that for bare CeO2. It may be due to the fact that bare CeO2 contributes to UV light absorption. Moreover CeO2 coupled with CZTS has induced visible light absorption, separation and transmission of photoinduced charge carriers. However, the PL intensity of CZTS decorated CeO2 is significantly lower than that of the bare CeO2, which clearly demonstrates that the composite impedes the rapid recombination of electron–hole pairs.

N-doped graphene supported quaternary electrocatalyst (PtRuFeCo/NG) was synthesized and evaluated for potential oxygen reduction (ORR) and methanol oxidation reaction (MOR) in fuel cells. The catalyst exhibited excellent MOR (strong CO tolerance, lower onset potential), ORR (four electron transfer) activities and delivered maximum power densities of 778 and 122 mW cm−2 with direct methanol and proton exchange membrane fuel cells, respectively. The N-doping and synergistic effects of alloying low-cost Fe and Co with Pt and Ru makes PtRuFeCo/NG as excellent bifunctional catalyst that greatly reduces the processing cost of fuel cell which is the major problem facing the fuel cell industry.

Development of a novel and stable electrochemical sensor electrode for the sensitive and reliable determination of p-nitrophenol (p-NP) is of great importance to environment. In the present work, e...

The non-ionic surfactant, Tween 80 (T80) a material with promising applications in the pharmaceutical, cosmetic, and food industries, has been explored here for the design of novel nanostructures (NS). We report here a direct one-pot seedless green method for the synthesis of gold-silver (AuAg) hollow cubic NS, with gold (90%) being the major component. The concentration of T80 plays an important role in determining the shape of the NS. A minimum T80 concentration of 50 mM is required for the formation of hollow cubic NS, whose sizes are controlled by increasing the T80 concentration. The unique molecular structure of T80 directs its molecules to assemble into core-shell cylindrical micelles that act as a soft-template for the growth of the NS. Study of the mechanism for the formation of the NS suggests nucleation followed by co-reduction of metal ions and its growth into hollow cubic NS over T80 micelles. The AuAg hollow cubic NS shows greater potential as efficient nanocatalysts than the non-cubic NS obtained at lower T80 concentrations. The hollowness and the cubic shape of the NS contribute towards their effective surface area that facilitates efficient catalytic activity. The AuAg NS may have biological applications due to their cell viabilities. Keywords: gold-silver nanostructures, Hollow cubic, Tween 80, Cylindrical micelle, Nanocatalysts

In this study, sonophotocatalytic decolorization of Begazol Black B by double-sided, sonoloaded nanophotocatalysts (nphs) on 3D porous substrate (3D-PS) was reported for the first time. Sonoloading is a facile fabrication route that allows two-sided loading of nphs on 3D-PS. Morphology of the 3D-PS and the presence of the nphs were studied using field emission scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. Moreover, the durability of the nphs on the 3D-PS was studied using X-ray fluorescence. The central composite design based on response surface methodology was employed to find the maximum yield of sonophotocatalytic decolorization and optimize the process variables (initial BBB concentration, initial H2O2 concentration, pH and ultrasonication time). Complete decolorization was achieved at only 40 min treatment under the optimum conditions. Moreover, sonoloaded nphs on 3D-PS exhibited 93% durability after 50 h sonophotocatalytic decolorization. The anticipated values of the decolorization efficiency showed excellent agreement with the experimental values (R2 = 0.9823, Adj-R2 = 0.9657). Furthermore, the kinetic analysis demonstrated that the sonophotocatalytic decolorization followed the Langmuir-Hinshelwood kinetic model. Finally, a comparative study between sonocatalytic, photocatalytic and sonophotocatalytic processes was conducted at the optimum condition. The results revealed that sonophotocatalytic process can markedly enhance the decolorization efficiency compared to sonocatalytic and photocatalytic methods due to the enhanced reactive radical generation.

We report an electrochemical sensor based on three-dimensional porous amorphous carbon (3DPAC) for the sensitive and selective determination of gallic acid (GA). The tailor-made carbon was prepared via salt-templating in which the organic molecular precursor, i.e., glucose, was simply ground and carbonized with a eutectic mixture of LiBr and KBr at 800 °C in an inert atmosphere. Salt removal from the carbon-salt mixture with water yielded 3DPAC with a hierarchical porous structure and oxygen-containing functional groups. When employed as an electrochemical sensor, 3DPAC exhibited remarkable sensitivity (0.1045 µA pM−1 cm−2) with a lower detection limit of 0.434 pM at a signal-to-noise ratio of 3 and a linear response up to 1–150 pM for determination of GA. Under optimized test conditions, 3DPAC showed a superior peak current response for GA as compared to the glassy carbon electrode. In addition, ascorbic, uric, and caffeic acids did not interfere with the voltammetric detection of GA in terms of selectivity, stability, and repeatability. We envision that 3DPAC can provide a promising platform for the development of electrochemical sensors.

Unique Ni2CoS4-carbon nanofiber (CNF) composite nanostructures were fabricated using a simple electrospinning-assisted hydrothermal route and used for the rapid and accurate electrochemical oxidation of glucose in real samples at the trace level. Electrochemical impedance spectroscopy and cyclic voltammetry of unmodified and modified electrodes revealed low charge-transfer resistance and the excellent electrocatalytic sensing of glucose when using the Ni2CoS4-CNF at a low potential due to the combined benefits of the highly conductive Ni2Co2S4 anchored to the large surface area of the CNFs. Amperometric analysis of the fabricated sensor has shown an extremely low limit of detection (0.25 nM) and a large linear range (5–70 nM) for glucose at a working potential of 0.54 V (vs. Hg/HgO). The practicability of the Ni2CoS4-CNF for use in glucose determination was tested withl human saliva, blood plasma, and fruit juice samples. The Ni2CoS4-CNF/GCE showed acceptable recovery values for human saliva (99.1–100.8%), blood plasma (98.6–101.5%), and fruit juice (95.1–105.7%) samples. The proposed sensor also exhibited outstanding electroanalytical characteristics for glucose oxidation in these samples, including reusability, repeatability, and interference resistance, even in the presence of other biological substances and organic and inorganic metal ions.

Nanofabrication of the heteroatom doped metal oxides into a well-defined architecture via a "bottom-up" approach is crucial to overcome the boundaries of the metal oxides for the energy storage systems. In the present work, we have demonstrated such a dilemma may turn out to be well-addressed by developing the sulfur doped bimetallic cobalt tungstate (CoWO 4 ) porous nanospheres for the efficient hybrid supercapacitor via a single step, ascendable bottom-up approach. The combined experimental and kinetics studies reveal that the enhanced electrical conductivity, porosity, and openness for the ion migration after amendments of the CoWO 4 via sulfur. As a result, the Sulfur doped CoWO 4 nanospheres exhibit a specific capacity of 248.5 mAh g -1 with outstanding rate capability and cycling stability. Assembled hybrid supercapacitor cell with sulfur doped CoWO 4 nanospheres and activated carbon electrodes could be driven reversibly in a voltage of 1.6 V and exhibits a specific capacitance of 177.25 F g -1 calculated at 1.33 A g -1 with an energy density of 63.41 Wh kg -1 at 1000 W kg -1 power density. In addition, the hybrid supercapacitor delivers 94.85% initial capacitance over 10,000 charge-discharge cycles. The excellent supercapacitive performances of Sulfur doped CoWO 4 nanospheres may well be credited to the Sulfur doping and bottom-up fabrication of the electrode materials.

Selenium-enriched nickel selenide (NiSe-Se) nanotubes supported on highly conductive nickel foam (NiSe-Se@Ni foam) were synthesized using chemical bath deposition with the aid of lithium chloride as a shape-directing agent. The uniformly grown NiSe-Se@Ni foam, with its large number of electroactive sites, facilitated rapid diffusion and charge transport. The NiSe-Se@Ni foam electrode exhibited a superior specific capacitance value of 2447.46 F g

A colorimetric polydiacetylene (PDA) paper strip sensor that can specifically recognize Bacillus thuringiensis (BT) HD-73 spores is described in this work. The target-specific aptamer was combined with PDA, and the aptamer-conjugated PDA vesicles were then coated on polyvinylidene fluoride (PVDF) paper strips by a simple solvent evaporation method. The PDA-aptamer paper strips can be used to detect the target without any pre-treatment. Using the paper strip, the presence of BT spores is directly observable by the naked eye based on the unique blue-to-red color transition of the PDA. Quantitative studies using the paper strip were also carried out by analyzing the color transitions of the PDA. The specificity of this PDA sensor was verified with a high concentration of Escherichia coli, and no discernable change was observed. The observable color change in the paper strip occurs in less than 1 h, and the limit of detection is 3 &times, 107 CFU/mL, much below the level harmful to humans. The PDA-based paper sensor, developed in this work, does not require a separate power or detection device, making the sensor strip highly transportable and suitable for spore analysis anytime and anywhere. Moreover, this paper sensor platform is easily fabricated, can be adapted to other targets, is highly portable, and is highly specific for the detection of BT spores.

Selectivity of catalysts toward harmful cationic pollutants in industrial wastewater remains challenging but is of crucial importance in environmental remediation processes. Here, we present a complex network of a hydrolyzed polymer of intrinsic microporosity (HPIM)-based electrospun nanofibrous web with surface functional decoration of ZnO nanorods (NRs) as a hierarchical platform for selective and rapid degradation of cationic dyes. Over a single species or binary mixtures, cationic dyes were selectively adsorbed by the HPIM surface, which then rapidly degraded under simultaneous photoirradiation through the ZnO NRs. Both HPIM and ZnO exhibited high electronegative surfaces, which induced the selectivity towards the cationic dyes and rapidly degraded the pollutants with the production of reactive oxygen species under photoirradiation. Further, as a free-standing web, the catalytic network could be easily separated and reused without any significant loss of catalytic activity after multiple cycles of use. The hierarchical platform of ZnO/HPIM-based heterostructures could be a promising catalytic template for selective degradation of synthetic dyes in mixed wastewater samples. (C) 2019 Elsevier Inc. All rights reserved.

In this work, multifunctional Fe-aminoclay (FeAC)/carboxymethyl cellulose (CMC)/ polyhedral oligomeric silsesquioxane (POSS) composite (FeAC/CMC/POSS) with layered structure was successfully synthesized and utilized as adsorbent for the removal of cesium ions (Cs+) and cationic dyes methylene blue (MB) and chrysoidine G (CG) from aqueous solutions. The FeAC/CMC/POSS exhibit excellent adsorption capacities for Cs+ ions, MB and CG of 152, 438, and 791 mg g–1, respectively. The adsorption capacities for Cs+ ions, MB and CG are substantially greater than those of many previously reported adsorbents due to (i) the layered morphology of the composite and abundance of amino (−NH2) groups on clay surface and (ii) existence of carboxylate (−COO–) and hydroxyl (−OH–) groups on the CMC backbone, which contribute to the adsorption of large number of Cs+ ions and dye molecules through electrostatic attraction and ion-exchange process. More importantly, the incorporation of POSS increases the interlayer spacing of Fe-a...

SnO2 composite materials infiltrated into the hollow carbon channels of a crab-shell biotemplate were hydrothermally synthesized and utilized as anodes for lithium-ion batteries. Varying the reaction temperatures and times of the hydrothermal reaction yielded different SnO2 nanoparticle shapes, characterized by scanning electron microscopy and transmission electron microscopy. The materials prepared at 100 °C (sample S100) were spherical, amorphous in nature, and successfully infiltrated into the hollow carbon channels, while those prepared at 180 °C (sample S180) yielded many rod-like particles on the outer surfaces of the channels. The S100 electrode exhibited better cyclability, corresponding to a capacity of 298 mAh g-1 at 100 cycles, and high rate capability with a capacity retention of 54% at 3 A g-1. The enhanced electrochemical performance of S100 could be attributed to the configuration of the SnO2 particles infiltrating the carbon-coated hollow channels, which accommodated large volume changes during (de)lithiation.

Upconversion Sr2(Gd.98-xEr.02Ybx)8Si6O26 (SGSO:2Er3+/xYb3+) phosphor materials were synthesized using a citrate sol-gel process. X-ray diffraction patterns confirmed their hexagonal structure. Field emission scanning electron microscopy images of SGSO:2Er3+/xYb3+ phosphors depicted submicron particles. The enhanced upconversion luminescence properties of SGSO:2Er3+/xYb3+ phosphors were analysed as a function of Yb3+ ion concentration and laser power. The energy transfer induced enhanced emission of the Er3+/ Yb3+ ions co-doped SGSO phosphors was ascribed to multi-phonon relaxation. The calculated chromaticity coordinates of the SGSO:2Er3+/xYb3+ phosphors showed emissions could be tuned by changing Yb3+ ion concentration. Optimized sample exhibited the chromaticity coordinate values near to the ultra-high definition television standard green emission coordinates.

Fluorescence intensity ratio (FIR)-based optical thermometry has attracted a great deal of attention because it allows accurate and reliable temperature measurements with high spatial resolution and real-time monitoring. Herein, we report the novel Sr2Gd8(SiO4)6O2:Er3+ (SGSO:Er3+) phosphor as an optical thermometry material. The sol-gel method is used to synthesize the oxyapatite structured SGSO:Er3+ phosphors, which exhibits a rod-like morphology. The photoluminescence spectra of SGSO:Er3+ phosphors displays two distinct green emission bands corresponding to the electronic transitions 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2. The temperature-induced variations in the FIR result in a maximum sensitivity of 3.4 × 10−3 K−1 at 463 K. Further, the CIE chromaticity coordinates do not shift from the green region when the temperature is increased from 303 to 483 K and the color purity only decreasing from 77.6 to 71.4%. The SGSO:2Er3+ phosphor exhibits the color-purity of 93.5% when excited with low-energy electron beam. These results suggest that the SGSO:2Er3+ phosphor is a promising material for optical temperature sensors and display devices.

A customized droplet-based microfluidic reactor was fabricated for the synthesis of silver nanoparticles (Ag NPs) using silver nitrate (AgNO3) and branched polyethyleneimine (BPEI) as a precursor and a reducing agent, respectively. The effects of static mixing, temperature, and the volumetric flow rates of AgNO3 and BPEI on the particle size were investigated. The use of a static mixer and the optimization of the reaction temperature enhanced the monodispersity of the Ag NPs. In addition, the size of the Ag NPs was manipulated by changing the flow rate ratio of AgNO3 to BPEI at 60 °C for 60 min.

Although sodium hybrid capacitors (NHCs) have emerged as one of the most promising next-generation energy storage systems, further advancement is delayed primarily by the absence of high-performance battery-type anodes. Herein, we report a nature-inspired synthesis route to prepare hard carbon anodes with high capacity, rate capability, and cycle stability for dual-carbon NHCs. Shape- and size-controllable crystal aggregates of inexpensive triazine molecules are utilized as reactive templates that perform triple duties of structure-directing agent, porogen, and nitrogen source. This enables the fine control of microstructure/morphology/composition and thereby electrochemical reactions toward Na-ion. The resulting hard carbon optimized in terms of lateral size, interlayer spacing, and surface affinity of graphene-like layers achieves a specific capacity of ∼380 mAh/g after 100 cycles at a current density of 250 mA/g mainly

Here, we designed and synthesized a recoverable multifunctional adsorbent using a microfluidic reaction system and evaluated the removal performance of the smart adsorbent toward radioactive cesium as a model sample. Prussian blue-laden magnetic micro-adsorbents (PB-MNPs-MAs) with uniform morphology and monodispersity were generated via two-step sequential procedures using a glass capillary microfluidic system, followed by chemical co-precipitation with a high production rate. The cesium removal efficacy of the PB-MNPs-MAs was analyzed based on Langmuir and Freundlich isotherms by controlling adsorption parameters such as adsorbent size, initial cesium concentration, and contact time. The adsorption isotherm of the PB-MNPs-MAs was better fitted to the Langmuir model with a maximum cesium adsorption capacity of 58.73 mg g−1, which was 40% higher than that of macro-adsorbents in a dynamic magnetic field. This result can be attributed to their large specific area, which increased the kinetic rate of cesium adsorption and achieved saturation within 20 min. Additionally, the PB-MNPs-MAs were recovered from wastewater within 5 s under a static magnetic field, indicating their great potential for magnetic actuation. We believe that our PB-MNPs-MAs can encapsulate nano-functional adsorbents and prevent actuation, making them promising for environmental remediation and especially for removal of radionuclides.

Metal nanoparticle-containing porous organic polymers have gained great interest in chemical and pharmaceutical applications owing to their high reactivity and good recyclability. In the present work, a palladium nanoparticle-decorated triazine-urea-based porous organic polymer (Pd@TU-POP) was designed and synthesized using 1,3-bis(4-aminophenyl)urea with cyanuric chloride and palladium acetate. The porous structure and physicochemical properties of the electrode material Pd@TU-POP were observed using a range of standard techniques. The Pd@TU-POP material on the electrode surface showed superior sensing ability for rutin (RT) because the Pd dispersion facilitated the electrocatalytic performance of TU-POP by reducing the overpotential of RT oxidation dramatically and improving the stability significantly. Furthermore, TU-POP provides excellent structural features for loading Pd nanoparticles, and the resulting Pd@TU-POP exhibited enhanced electron transfer and outstanding sensing capability in a linear range between 2 and 200 pM having a low detection value of 5.92 × 10

We describe a facile, economic, and environment friendly green method for simultaneous detection of palladium ions (Pd2+) and recovery Pd nanoparticles (Pd NPs) from wastewater through a non-toxic gamma-irradiation based reduction reaction. Basic orange 2 (BO), an azo dye, is used as a sensing probe in Pd2+ detection and acts as a stabilizing agent in the recovery of monodispersed small Pd NPs. The presence of Pd2+ in waste water was easily observed by naked eye through the color change from yellow to red upon adding the Basic orange 2. More importantly, Pd forms a square-planar structured complex with Pd2+ which aids the development of smaller and monodispersed Pd NPs during radiolytic reduction. The size control mechanism during the recovery of Pd NPs was ascertained by varying the intensity of gamma-ray (from 10 to 50 kGy) and initial concentrations of Pd2+ (from 20 to 100 ppm). We are able to control the size of Pd NPs from 5 to 400 nm by irradiating gamma-ray doses from 1 and 50 kGy, as evident from UV-vis absorption spectra (UV-vis) and transmission electron microscopy (TEM) images. About 15 nm colloidal Pd NPs were formed at 10 kGy gamma-irradiation, and various sizes of aggregates, which may be attributed to Ostwald ripening crystal growth, were observed in the irradiation condition of 20 to 50 kGy. Further, the size of the recovered Pd NPs increases as the Pd2+ concentration increased, due to the increase in the ion association rate. Our proposed green method is a promising strategy that can easily detect Pd2+ from waste water and recover Pd NPs in desired size and morphology.

A polymer hydrogel composed of alginate/humic acid/Fe-aminoclay was fabricated and utilized as a potential adsorbent for the removal of strontium ions (Sr 2 + ) from aqueous solution. The effects of adsorbate concentration, reaction pH, and time on the removal efficiency of Sr 2 + were investigated. The results revealed that the adsorption capacity increases as the Sr 2 + concentration increased from 1 to 10 ppm, which might be due to the more available adsorption sites. An additional increase in the Sr 2 + concentration had no effect. The optimal pH and reaction time for the removal of Sr 2 + were identified as pH 7 and 24 h, respectively, with an adsorbent dosage of 20 mg. The adsorption isotherm was fitted to the Freundlich model with a maximum Sr 2 + adsorption capacity of 45.65 mg g−1. The kinetic study showed that the adsorption behavior followed a pseudo-second-order kinetics. The hydrogel showed good selectivity toward Sr 2 + even in the presence of competitive cations having a higher concentration than Sr 2 + . From the above results, it is expected that this biocompatible hydrogel material can be used as an adsorbent for the removal of radioactive strontium.

Here, we demonstrate the controlled synthesis of nanoporous carbon and cobalt oxide (NPC Co3O4) composite from a single precursor source zeolitic imidazolate framework-67, which leads to some new interesting electrochemical properties. The composite shows an outstanding electrochemical performance for measuring the oxidation of glucose in alkaline solution. The differential pulse voltammetric response of the NPC–Co3O4 composite electrode for the sensing of glucose exhibits a linear relation with the concentration range of 5 × 10−12–2.05 × 10−10 M and a low detection limit of 2 × 10−12 M. The fabricated sensor shows high sensitivity, reliable reproducibility, and good selectivity. The sensor, when used for the direct determination of glucose in blood serum samples, shows good recovery (98.5–101.0%), suggesting its feasibility for biomedical applications. In addition, in a given potential range of 0–1 V, the composite exhibits a high capacitance (885 F g−1 at a current density of 2.5 A g−1) and long cycle life (∼94% capacitance retention after 10,000 cycles).

CdSe quantum dots (QDs) with a uniform size distribution were synthesized using a droplet-based microfluidic reactor. The droplet-based microfluidic reactor enabled continuous production of CdSe QDs at a temperature of less than 250 °C in an extremely shorter reaction time (less than 30 s) when compared with the batch reactor. The photoluminescence (PL) and ultraviolet (UV) absorption spectra of the CdSe QDs were recorded at different reaction times and the size and optical properties of the QDs were discussed. The structure morphology and elemental composition of the CdSe QDs were determined using a transmission electron microscopy (TEM) and electrondispersive spectroscopy (EDS). The size of CdSe QDs prepared using the microfluidic reactor was estimated to be from 1.6 to 2.6 nm with an average size of 2.2 nm. This droplet-based microfluidic reactor has the potential to be automated system continuous synthesis of CdSe QDs.

Sung-Chan Jang,1,2,* Sung-Min Kang,1,* Jun Young Lee,3,* Seo Yeong Oh,1 AT Ezhil Vilian,4 Ilsong Lee,1,2 Young-Kyu Han,4 Jeong Hoon Park,3 Wan-Seob Cho,5,* Changhyun Roh,2,6 YunSuk Huh1 1Department of Biological Engineering, Biohybrid Systems Research Center (BSRC), Inha University, Incheon, 2Biotechnology Research Division, 3Radiation Instrumentation Research Division, Advanced Radiation Technology Institute (ARTI), Korea Atomic Energy Research Institute (KAERI), Jeongeup, 4Department of Energy and Materials Engineering, Dongguk University, Seoul, 5Laboratory of Toxicology, Department of Medicinal Biotechnology, College of Health Sciences, Dong-A University, Busan, 6Radiation Biotechnology and Applied Radioisotope Science, University of Science and Technology (UST), Daejeon, Republic of Korea *These authors contributed equally to this work Introduction: Positron emission tomography (PET) tracers has the potential to revolutionize cancer imaging and diagnosis. PET tracers offer non-invasive quantitative imaging in biotechnology and biomedical applications, but it requires radioisotopes as radioactive imaging tracers or radiopharmaceuticals. Method: This paper reports the synthesis of 18F-nGO-PEG by covalently functionalizing PEG with nano-graphene oxide, and its excellent stability in physiological solutions. Using a green synthesis route, nGO is then functionalized with a biocompatible PEG polymer to acquire high stability in PBS and DMEM. Results and discussion: The radiochemical safety of 18F-nGO-PEG was measured by a reactive oxygen species and cell viability test. The biodistribution of 18F-nGO-PEG could be observed easily by PET, which suggested the significantly high sensitivity tumor uptake of 18F-nGO-PEG and in a tumor bearing CT-26 mouse compared to the control. 18F-nGO-PEG was applied successfully as an efficient radiotracer or drug agent in vivo using PET imaging. This article is expected to assist many researchers in the fabrication of 18F-labeled graphene-based bio-conjugates with high reproducibility for applications in the biomedicine field. Keywords: graphene oxide, nanocomposite, imaging, radiotracer

Since the commercialization of white light-emitting diodes (WLEDs) in 1996, they are rapidly replacing conventional lighting sources and have become an essential commodity for day-to-day human life. At present, most of the WLEDs existing in the market are rare-earth based, which are very limited, expensive and often not available due to monopolistic supply conditions. Hence, there is a serious demand for novel rare-earth free phosphors to achieve cost-effective and energy-efficient WLEDs with excellent luminous efficacy for general illumination. Herein we report on highly efficient rare-earth free Cs(1−x)RbxVO3 phosphors as a single emitting compound for near UV-based WLEDs manufactured by the citrate sol–gel method for the first time. Rietveld refinement is performed for the X-ray diffraction patterns of the CsVO3 host and CsVO3:0.25Rb phosphors to reveal their orthorhombic pyroxene structure. The difference in the ionic radii of Rb+ and Cs+ ions led to a more distorted VO43− tetrahedron with a broken Td symmetry, which allows spin forbidden transitions for CsVO3:0.25Rb phosphors, resulting in enhanced internal and external quantum efficiencies of 94.7% and 84.5% along with superior luminescence properties compared to the CsVO3 host. When varying the input current from 20 to 200 mA, the fabricated WLED exhibited a good color rendering index of 69.7–81.5 and an extremely high luminous efficacy of 94.8–58.7 lm W−1, which are among the highest values for the same host lattice. These rare-earth free CsVO3:0.25Rb phosphors with a single emitting center may emerge as a new class of advanced inorganic phosphors for near UV-based WLEDs in the lighting industries.

Evolution of a simple, efficient and reproducible strategy for the rational design of hierarchically structured metal chalcogenide-based supercapacitors has attracted considerable research interest in recent years. Herein, a facile wet-chemistry approach is employed to design three-dimensional forest-like porous nickel sulfide nanotrees on nickel foam (NiS NTs/Ni foam) for use as a cathode material in hybrid supercapacitors. The growth time plays a crucial role in controlling the surface morphology, and the optimal growth conditions (3 h at 85 °C) led to the growth of forest-like NiS NTs/Ni foam with reliable adherence. The forest-like NiS NTs/Ni foam shows maximum areal and specific capacities of 752.71 μA h cm−2 and 342.1 mA h g−1 at a current density of 4 mA cm−2, with an excellent cycling stability of 89.4%. This result is primarily due to the availability of more surface-active sites in the well-defined hierarchical architecture, which allow the rapid diffusion of electrolyte ions and minimize the electron transport limitation. Utilizing the hierarchical NiS NTs/Ni foam as a cathode and activated carbon-based anode, we further fabricated a hybrid supercapacitor, which demonstrates a wide potential window of 1.6 V with high areal energy and power densities of 0.472 mW h cm−2 and 21.5 mW cm−2, respectively. The fabricated hybrid supercapacitor is successfully utilized to drive various electronic gadgets for real-life applications. The electrochemical performance of a hierarchically structured NiS-based binder-free electrode with our facile approach paves a new pathway for the development of novel metal chalcogenides for high-performance hybrid supercapacitors.

Reduced graphene oxide (RGO) incorporated onto metal–organic framework (MOF)-derived Co3O4 hexagons is prepared via a hydrothermal route for supercapacitor and glucose sensor applications. Various analysis techniques demonstrate that the Co3O4 hexagons were uniformly spread over the thin graphene sheets to assist the electron accessibility of the electrode materials. Under optimized conditions, using 0.1 M KOH electrolyte at a current density of 4 A g−1, a specific capacitance value of 1300 F g−1 is obtained. The fabricated asymmetric supercapacitor cycled reversibly and exhibits high energy and power density values of 65.8 W h kg−1 and 2048 W kg−1, respectively, over the voltage range of −0.1 V to 0.4 V. The asymmetric supercapacitor shows 80.5% capacitance retention even after 5000 cycles at a current density of 4 A g−1, which indicates its high cycling stability in view of the fact that it is binder-free. Furthermore, the RGO–Co3O4 hexagon-modified electrode was optimized to realize the reliable amperometric determination of glucose concentration with a very low detection limit and excellent sensitivity value of 0.4 μM and 1.315 mA mM−1 cm−2, respectively. All of these remarkable performance indicators suggest that RGO–Co3O4 is a promising electrode material for next-generation energy storage devices and electrochemical sensors.

We report a facile and large-scale synthesis of size-tunable and nontoxic mesoporous silica-coated Gd2O3:Eu3+ (Gd@mSi) core–shell nanostructures using a TPAOH assisted modified UHP technique. The role of TPAOH in controlling the particle size was evaluated. The potentiality of these Gd@mSi core–shell nanoparticles before and after folic acid conjugation was established by in vitro fluorescence microscopy of the U2OS cell lines for cancer imaging and therapy.

Metal-organic frameworks are a novel class of organic-inorganic hybrid polymer with potential applications in bioimaging, drug delivery, and ROS therapy. NH2-MIL-125, which is a titanium-based metal organic framework with a large surface area of 1540m2/g, was synthesized using a hydrothermal method. The material was characterized by powder X-ray diffreaction (PXRD), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM), and N2 isotherm analyses. The size of the polymer was reduced to the nanoscale using a high-frequency sonication process. PEGylation was carried out to improve the stability and bioavailability of the NMOF. The as-synthesized nano-NH2-MIL-125/PEG (NMOF/PEG) exhibited good biocompatibility over the (Cancer) MCF-7 and (Normal) COS-7 cell line. The interaction of NMOF/PEG with the breast cancer cell line (MCF-7) was examined by BIO-TEM analysis and laser confocal imaging. 2',7'-dichlorofluorescin diacetate (DCFDA) analysis confirmed that NMOF/PEG produced free radicals inside the cancer cell line (MCF-7) upon visible light irradiation. NMOF/PEG absorbed a large amount of DOX (20wt.% of DOX) and showed pH, and photosensitive release. This controlled drug delivery was attributed to the presence of NH2, Ti group in MOF and a hydroxyl group in PEG. This combination of chemo- and ROS-therapy showed excellent efficiency in killing cancer MCF-7 cells.

In this study, we have synthesized N-doped graphene (NG) supported ternary PtRuFe nanocatalyst with size ranging from 2 to 3 nm using microwave-assisted polyol method and evaluated its electrochemical activity towards methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) in direct methanol fuel cell (DMFC) and proton exchange membrane fuel cell (PEMFC), respectively. The as-prepared bifunctional PtRuFe/NG catalyst exhibited excellent electrocatalytic activity towards both MOR and ORR. During MOR, the PtRuFe/NG catalyst showed the stronger CO tolerance, lower onset potential, and higher methanol oxidation current than that of its un-doped counterpart (PtRuFe/rGO). In ORR, the catalyst exhibited higher oxygen reduction current with four electron transfer. The maximum power density delivered by PEMFC and DMFC using PtRuFe/NG were 870 and 112 mW cm−2, respectively, which are 25% higher than that of its un-doped counterpart. Also PtRuFe/NG showed 2- to 3-fold improvement in MOR, ORR, PEMFC and DMFC performances as compared with previously reported values of mono-, bi-, and tri-metallic catalysts supported on NG and other carbon substrates. The enhanced electrochemical activity may be attributed to the synergetic effect of nitrogen-doping along with the bi-functional and ligand effects of alloying low-cost Fe with Pt and Ru. The bifunctional ternary PtRuFe nanocatalysts supported on N-doped graphene has excellent potential to catalyze both MOR and ORR with remarkable reduction in the processing cost of fuel cells which is the primary problem facing the commercialization of fuel cells.