Bifunctional Role Research Articles

The bifunctional role of copper nanoparticles in tomato: Effective treatment for Fusarium wilt and plant growth promoter

Both the effectiveness of copper nanoparticles (Cu-NPs) as a treatment for Fusarium wilt and the role of Cu-NPs in promoting tomato plant growth were studied. First, we evaluated the in vitro antifungal activity of Cu-NPs at different concentrations (0.1, 0.25, 0.5, 0.75, and 1.0 mg/mL) against Fusarium oxysporum f. sp. lycopersici (FOL). A strong inhibitory effect on mycelial FOL growth (67.3%) was observed with 0.5 mg/mL Cu-NPs compared to a commercial fungicide based on copper hydroxide, whose inhibitory effect was only 15.6%. Next, in in vivo experiments at the same concentration, Cu-NPs significantly diminished the symptoms of Fusarium wilt by 68 and 66.5% for incidence and severity, respectively. Moreover, the treatments with Cu-NPs increased the growth of tomato plants and particularly raised the chlorophyll content (from 19.3 to 28.6%). This is because Cu-NPs effectively deliver copper as a micronutrient for the plants, while the uncontrolled uptake of copper ions from the commercial fungicide (copper hydroxide) inhibits the healthy development of plants. Importantly, despite the principal function of Cu-NPs as a fungicide, Cu-NPs may be applied as fertilizer for tomato plants. Thus, the application of Cu-NPs effectively treats Fusarium wilt while promoting the growth of tomato plants. Therefore, these results suggest that copper nanomaterials may be used as both a source of micronutrients in cases of soil copper deficiency and as a fungicide. In terms of sustainability, this multifunctionality has the potential to positively impact the environment.

Dual-signal readout aptasensor for electrochemical and colorimetric assay using a bifunctional Ni-Fe PBA probe

We report a dual-readout, electrochemical (EC) and colorimetric aptasensor for accurate assay of disease biomarkers, based on the Ni-Fe prussian blue analogue (Ni-Fe PBA) as a bifunctional signal probe. Specifically, the redox of plural metal ions in Ni-Fe PBA endows it with excellent redox-activity, providing an obviously well-defined redox current for EC detection. Meanwhile, the peroxidase-like activity of Ni-Fe PBA can catalyze the decomposition of H2O2 and oxidation of chromogenic substrate (TMB), which is beneficial for colorimetric analysis. Based on the excellent redox-activity and peroxidase-like activity of the bifunctional Ni-Fe PBA, we realized dual-readout EC and colorimetric detection of platelet-derived growth factor BB (PDGF-BB). This single probe (Ni-Fe PBA) acting as bifunctional roles depends on two different mechanisms and relatively independent signal transduction, which avoids fussy assembly of diverse probes and decreases the uncontrollable factor in different batches. As a result, an EC-colorimetric dual-readout aptasensor shows two linear responses in the range of 0.0001–5 nM and 0.01–50 nM for PDGF-BB, providing more accurate and reliable results compared with the traditional single-signal readout method. The as-designed dual-readout aptasensor is easy to fabricate, highly accurate and reliable, having promising applications in bioanalysis.

Efficient Co@Co3O4 core-shell catalysts for photocatalytic water oxidation and its behaviors in two different photocatalytic systems

Co@Co 3 O 4 photocatalyst was prepared in situ to investigate its water splitting performance and mechanism in two photocatalytic systems. • Photocatalytic activity of catalyst 1 in two systems were compared for the first time. • Catalyst 1 exhibited excellent photocatalytic performances. • Core-shell structure of Catalyst 1 can promote light capture and electron transmission. The photocatalytic performances of water oxidation were usually carried out in two different systems, photosensitizer and non-photosensitizer systems. There is few report about the same catalyst used in two systems and therefore it is of great significant to compare its role of the same catalyst in two systems and explore its different reaction mechanisms. In this work, first 4 kinds of metallic Co microparticles were obtained by different reduction methods through hydrothermal processes, and Co@Co 3 O 4 core-shell microparticles (1–4) were obtained from these metallic Co microparticles oxidized in air or in the reacting solution in situ. The core-shell structure of 1 was characterized by a series of analytical techniques. 1–4 exhibited excellent activities and stabilities in the [Ru(bpy) 3 ] 2+ /S 2 O 8 2− /light system when they were used as catalysts for the photocatalytic water oxidation. The maximum O 2 evolution of 1 after 20 min’s illumination was 98.2 μmol, the O 2 yield was 65.5%, the initial turnover frequency was 6.6 × 10 −3 , the initial quantum efficiency ( Φ QY initial ) was 15.0% higher than Co (8.3%), CoO (11.7%), Co 2 O 3 (1.2%), Co 3 O 4 (2.8%) and 5 (2.2%). Even after the sixth run, the catalytic activity of recovered 1 still remained 85.1% of initial activity. In addition, the photocatalytic performances of 1 in the [Ru(bpy) 3 ] 2+ /S 2 O 8 2− /light system and S 2 O 8 2− /light system were compared for the first time. In the non-photosensitizer system, 1 shows bifunctional roles and acts as optical absorption center and active catalytic site, and oxygen evolution rate is lower and it takes longer time. In the photosensitizer system, 1 only acts as a catalyst, the photosensitizer enhances the light absorption and promotes water oxidation reaction with higher O 2 yield and QE, meanwhile the photosensitizer brings the defect of high cost and instability into the system. Based on the results the two different reaction mechanisms were deeply discussed.

The Small GTPase Rab5c Exerts Bi-Function in Singapore Grouper Iridovirus Infections and Cellular Responses in the Grouper, Epinephelus coioides.

The small GTPase Rab5 is one of the master regulators of vesicular trafficking that participates in early stages of the endocytic pathway, such as endocytosis and endosome maturation. Three Rab5 isoforms (a, b, and c) share high sequence identity, and exhibit complex functions. However, the role of Rab5c in virus infection and cellular immune responses remains poorly understood. In this study, based on the established virus-cell infection model, Singapore grouper iridovirus (SGIV)-infected grouper spleen (GS) cells, we investigated the role of Rab5c in virus infection and host immune responses. Rab5c was cloned from the orange-spotted grouper, Epinephelus coioides, and termed EcRab5c. EcRab5c encoded a 220-amino-acid polypeptide, showing 99% and 91% identity to Anabas testudineus, and Homo sapiens, respectively. Confocal imaging showed that EcRab5c localized as punctate structures in the cytoplasm. However, a constitutively active (CA) EcRab5c mutant led to enlarged vesicles, while a dominant negative (DN) EcRab5c mutant reduced vesicle structures. EcRab5c expression levels were significantly increased after SGIV infection. EcRab5c knockdown, or CA/DN EcRab5c overexpression significantly inhibited SGIV infection. Using single-particle imaging analysis, we further observed that EcRab5c disruption impaired crucial events at the early stage of SGIV infection, including virus binding, entry, and transport from early to late endosomes, at the single virus level. Furthermore, it is the first time to investigate that EcRab5c is required in autophagy. Equally, EcRab5c positively regulated interferon-related factors and pro-inflammatory cytokines. In summary, these data showed that EcRab5c exerted a bi-functional role on iridovirus infection and host immunity in fish, which furthers our understanding of virus and host immune interactions.

6-Formylindolo[3,2-b]carbazole reduces apoptosis induced by benzo[a]pyrene in a mitochondrial-dependent manner.

Benzo[a]pyrene (B[a]P), a potent carcinogen, has been proved that it can induce apoptosis via activation of the aryl hydrocarbon receptor (AhR) pathway. The metabolite of tryptophan 6-formylindolo[3,2-b]carbazole (FICZ), an endogenous activator of AhR, plays bifunctional roles in cell growth and apoptosis. However, whether and how FICZ can reduce the toxicity of B[a]P and the mechanism underlying this remain unclear. In this study, FICZ interfered with the toxicity of B[a]P in mouse hepatocarcinoma cell line Hepa1-6. The results of the MTT assay indicated that FICZ and B[a]P made opposite effects on cell proliferation. The scratch-wound healing assay showed that B[a]P (1 µM for 24 hr) exposure triggered cell migration and that was inhibited by FICZ (10 nM). In addition, FICZ ameliorated B[a]P-induced apoptosis by inhibiting reactive oxygen species generation and caspase-3 activation, as well as increasing reduced glutathione level in mitochondria. Furthermore, gene expression analyses indicated that FICZ competed with B[a]P, which reduced the transcriptional activation of the cyp1a1 and cyp1b1 genes, as well as Bcl2 and P53. Accordingly, the interaction between FICZ and B[a]P in the AhR pathway inhibited apoptosis in a mitochondrial-dependent manner, suggesting that endogenous compound may reduce the toxicity of exogenous pollutant in vivo and providing an available way to improve health condition related to the hepatic metabolic disorder.

DBU‐Catalyzed Ring‐Opening and Retro‐Claisen Fragmentation of Dihydropyranones

We present a general protocol for the formal Michael addition of acetone to α,β‐unsaturated esters and amides, a transformation difficult to perform using current methods. The protocol comprises of an amidine catalyzed relay ring‐opening and fragmentation of 3,4‐dihydropyranones. The reaction proceeds under mild conditions, has a broad substrate scope and the products can be isolated in good to excellent yields. The method can be applied to homochiral substrates with total preservation of chiral information, generating products in high optical purity. Kinetic experiments supported by quantum chemical modeling indicate a mechanism in which the catalyst takes a bifunctional role, acting both as a Brønsted base and as a hydrogen‐bond donor.

Lamin B receptor: role on chromatin structure, cellular senescence and possibly aging

The nuclear envelope is composed by an outer nuclear membrane and an inner nuclear membrane, which is underlain by the nuclear lamina that provides the nucleus with mechanical strength for maintaining structure and regulates chromatin organization for modulating gene expression and silencing. A layer of heterochromatin is beneath the nuclear lamina, attached by inner nuclear membrane integral proteins such as Lamin B receptor (LBR). LBR is a chimeric protein, having also a sterol reductase activity with which it contributes to cholesterol synthesis. Lukasova et al. showed that when DNA is damaged by ɣ-radiation in cancer cells, LBR is lost causing chromatin structure changes and promoting cellular senescence. Cellular senescence is characterized by terminal cell cycle arrest and the expression and secretion of various growth factors, cytokines, metalloproteinases, etc., collectively known as senescence-associated secretory phenotype (SASP) that cause chronic inflammation and tumor progression when they persist in the tissue. Therefore, it is fundamental to understand the molecular basis for senescence establishment, maintenance and the regulation of SASP. The work of Lukasova et al. contributed to our understanding of cellular senescence establishment and provided the basis that lead to the further discovery that chromatin changes caused by LBR reduction induce an up-regulated expression of SASP factors. LBR dysfunction has relevance in several diseases and possibly in physiological aging. The potential bifunctional role of LBR on cellular senescence establishment, namely its role in chromatin structure together with its enzymatic activity contributing to cholesterol synthesis, provide a new target to develop potential anti-aging therapies.

Photochemically deposited Ir-doped NiCo oxyhydroxide nanosheets provide highly efficient and stable electrocatalysts for the oxygen evolution reaction

Abstract To achieve practical production of fuel from water, it is essential to develop efficient and durable electrocatalysts for the oxygen evolution reaction (OER). We report here that doping NiCoOOH nanosheets with 8% Ir leads to a low overpotential of only 260 mV for 50 mA/cm2, far better than previous OER catalysts. We synthesized this catalyst using a novel photochemical deposition method that leads to a uniform distribution of dopant, large catalytic active area, high interfacial charge transfer efficiency, good adhesion between catalyst and matrix, and long lifetime. Moreover, these nanosheets show significant stable performance for 70 h in alkaline media. Our density functional theory calculations show that Ir and Co both play essential bifunctional roles in stabilizing the key O radical intermediate on Ir and promoting the O–O bond coupling on Co, which are optimum for the 8% Ir.

Cp*RuCl-Vinyl Carbenes: Two Faces and the Bifunctional Role in Catalytic Processes.

Ruthenium vinyl carbenes derived from Cp/Cp*RuCl-based complexes (Cp=cyclopentadiene, Cp*=1,2,3,4,5-pentamethylcyclopentadiene) have been routinely invoked as key intermediates in tandem reactions involving a carbene/alkyne metathesis (CAM). A priori, these intermediates resemble the Grubbs-type family of catalysts, but they exhibit a completely different reactivity pattern that few, if any, other catalytic system can reproduce so far. The reactivity of these species with α-unsubstituted and α-substituted alkynals showcases the peculiarities of these intermediates. Although Z-vinyl dihydrooxazines are preferentially obtained with the former, Z-vinyl epoxypyrrolidines are obtained with the latter. A combination of spectroscopic and computational data now prove that a η3 -coordination mode of the ruthenium vinyl carbene and the presence of a Lewis basic chloride ligand give rise to two markedly different stereoelectronic faces, which are responsible for the unconventional reactivity of these species.

Unraveling the role of Ti3C2 MXene underlayer for enhanced photoelectrochemical water oxidation of hematite photoanodes

Hematite is regarded as a promising photoanode for photoelectrochemical (PEC) water splitting. However, the charge recombination occurred at the interface of FTO/hematite strictly limits the PEC performance of hematite. Herein, we reported a Ti3C2 MXene underlayer modified hematite (Ti–Fe2O3) photoanode via a simple drop-casting followed by hydrothermal and annealing processes. Owing to the bifunctional role of Ti3C2 MXene underlayer in improving the interfacial properties of FTO/hematite and providing Ti source for the construction of Fe2TiO5/Fe2O3 heterostructure in hematite nanostructure, the bulk and interfacial charge transfer dynamics of hematite are significantly enhanced, and consequently enhancing the PEC performance. Compared with the pristine hematite, the as-prepared Ti–Fe2O3 photoanode shows an increased photocurrent density from 0.80 mA/cm2 to 1.30 mA/cm2 at 1.23 V vs. RHE. Moreover, a further promoted PEC performance including a dramatically increased photocurrent density of 2.49 mA/cm2 at 1.23 V vs. RHE and an obviously lowered onset potential is achieved for the Ti–Fe2O3 sample after the subsequent surface F-treatment and the loading of FeNiOOH cocatalyst. Such results suggest that the introduction of Ti3C2 MXene underlayer is a facile but effective approach to improve the PEC water splitting activity of hematite.

Modeling of low temperature steam reforming of flare gas to methane-rich fuel gas on Ni catalyst in different types of reactors

The results of mathematical modeling of fixed-bed catalytic reactors for low temperature low H2O/C steam reforming of propane-methane mixture and two real associated petroleum gases into methane-enriched fuel gas are reported. Three cases of practical interest were considered. In the first case, a lab-scale flow reactor, which is used for kinetic studies, was analyzed under assumption of constant wall/oven temperature. The possibility of noticeable hot and cold zones formation along the bed radius (4 mm) and length (33 mm) was predicted depending on the wall temperature and the ratios of H2O/C3H8 and C3H8/CH4. In the second case, a plant-scale adiabatic reactor was simulated, and the impossibility of conversion of flare gas with high C2+ fraction into fuel mixture with sufficiently high LHV (>31.8 MJ/m3) was predicted even if the post-removal of CO2 was assumed. In the third case, the advantages of a plant-scale tubular reactor against an adiabatic one were revealed for the reforming of “heavy” and “light” associated petroleum gas. The proposed bifunctional role of steam (first as a coolant, second as a reagent) increases the energy efficiency of tubular reformer due to recuperation of heat produced by reaction. The scheme with counter-current flows of reagent and coolant enabled to reduce twice the number of tubes in comparison with concurrent flow, but the catalyst temperature in the hot zone raised by 40°.

Bifunctional effect of Zoledronic Acid (ZA) on human mesenchymal stem cells (hMSCs) based on the concentration level

BackgroundTreatment of massive bone defects is a great challenge. Mesenchymal stem cells (MSCs) enhance bone regeneration by differentiating into osteoblasts. Bisphosphonates (BPs) are antiresorptives reducing bone resorption. Despite Medication-related osteonecrosis of the jaw (MRONJ) is a known side effect of antiresorptives, evidences suggest that BPs have positive effect on bone formation. The aims of this study were to investigate the effect of zoledronic acid (ZA) and geranylgeraniol (GGOH) on human mesenchymal stem cells (hMSCs) being a part of the bone microenvironment and evaluate whether low dose of bisphosphonate has enhanced osteogenic differentiation of hMSCs. Materials and methodsThe effect of ZA and GGOH on MSCs was investigated in addition to the effect of low doses of ZA on osteogenic differentiation of MSCs and analysed by WST-1, Live/Dead staining and coefficient of drug index (CDI). The osteogenic differentiation of the cells was confirmed by ALP activity, xylenol orange and alizarin red staining, microarray and PCR with levels of statistical significance indicated at *P<0.05, **P<0.01 and ***P<0.0001. Main findingsAlthough, high concentration of ZA had significantly decreased the cell viability in MSCs, GGOH reversed the action of ZA on the cells while at very high concentration; it caused severe reduction in the cell viability. CDI showed antagonism or synergism depending on the concentrations of ZA and GGOH. ConclusionThe treatment of cells with ZA has increased the mineralization and osteogenic differentiation of MSCs. Our study supported the hypothesis that zoledronic acid plays a bifunctional role depending on the concentration.

Graphene Quantum Dot Reinforced Electrospun Carbon Nanofiber Fabrics with High Surface Area for Ultrahigh Rate Supercapacitors.

High surface area, good conductivity, and high mechanical strength are important for carbon nanofiber fabrics (CNFs) as high-performance supercapacitor electrodes. However, it remains a big challenge because of the trade-off between the strong and continuous conductive network and a well-developed porous structure. Herein, we report a simple strategy to integrate these properties into the electrospun CNFs by adding graphene quantum dots (GQDs). The uniformly embedded GQDs play a crucial bifunctional role in constructing an entire reinforcing phase and conductive network. Compared with the pure CNF, the GQD-reinforced activated CNF exhibits a greatly enlarged surface area from 140 to 2032 m2 g-1 as well as a significantly improved conductivity and strength of 5.5 and 2.5 times, respectively. The mechanism of the robust reinforcing effect is deeply investigated. As a freestanding supercapacitor electrode, the fabric performs a high capacitance of 335 F g-1 at 1 A g-1 and extremely high capacitance retentions of 77% at 100 A g-1 and 45% at 500 A g-1. Importantly, the symmetric device can be charged to 80% capacitance within only 2.2 s, showing great potential for high-power startup supplies.

Ni(acac)2/Mo-MOF-derived difunctional MoNi@MoO2cocatalyst to enhance the photocatalytic H2evolution activity of g-C3N4

It is essential to construct bifunctional composite cocatalysts with earth-abundant metals for efficient transfer and separation of charge carriers, thus leading to the development of a photocatalyst with high H2 evolution activity. Herein, MoNi@MoO2 composite cocatalysts were prepared by annealing Ni-doped Mo-MOF, and then decorating with g-C3N4 by grinding. The obtained MoNi@MoO2-8 %/g-C3N4 photocatalyst exhibited an optimum H2 evolution rate of as high as 1.359 mmol g−1 h−1, 6.0 and 3.7 times than those of Ni/g-C3N4 and MoO2-8 %/g-C3N4, respectively. This improved activity can be ascribed to the bifunctional roles of MoNi@MoO2 and synergy between MoNi and MoO2. MoO2 acts as a reservoir to store electrons from g-C3N4; MoNi acts as surface-active sites to trap electrons from MoO2 and increase the proton reduction kinetics. This study would promote the development of other high-efficiency bifunctional cocatalysts to increase the photocatalytic H2 evolution performance.

Dissecting molecular events and gene expression signatures involved in Colletotrichum lindemuthianum-Phaseolus vulgaris pathosystem in compatible and incompatible interactions

Colletotrichum lindemuthianum, causal agent of bean anthracnose is one of the most destructive fungal bean diseases that potentially have an enormous economic impact on bean cultivation worldwide. To obtain novel insights into how bean regulates its defense pathways to react efficiently against this invading pathogen, cvs Khomein and Naz representing contrasting interactions were investigated by histochemical and real-time quantitative RT-PCR (RT-qPCR) approaches. Our histochemical analysis conducted at 24, 48, 72 and 96 h post inoculation (hpi) demonstrated that hydrogen peroxide (H2O2) may have a bifunctional role in establishing the incompatibility and compatibility. This free radical (H2O2) can, therefore, be elevated at an early stage (24 hpi) of the incompatible context to arrest fungal growth, whereas H2O2 was promoted at the late stage (72 hpi) of the compatible context to facilitate the infection process. Additionally, we demonstrated that O2− probably plays an essential function in launching the resistance response since O2− increased significantly at 36 hpi in incompatible interaction compared with that of the compatible interface. Our expression analysis showed that the expression of six defense-related genes are differentially regulated regarding the types of interactions, shedding light on how the beans adaptively regulate defense pathways. This study contributes to a better understanding of the kinetics of reactions triggered following C. lindemuthianum infection and may be applied to develop novel strategies to manage bean anthracnose effectively.

Inside Cover

The bifunctional roles of CH3COO– (complexation effect and decreasing temperature of PVP complete decomposition) are utilized to synthesize electrospun LaCoO3 perovskites at a low‐temperature 400 °C. The obtained material can be applied in the catalytic oxidation of volatile organic compounds, like stable propane. More details are discussed in the article by Luo and Qian et al. on page 144‐150. image

Bifunctional Role of the Sternohyoideus Muscle During Suction Feeding in Striped Surfperch, Embiotoca lateralis.

SynopsisIn ray-finned fishes, the sternohyoideus (SH) is among the largest muscles in the head region and, based on its size, can potentially contribute to the overall power required for suction feeding. However, the function of the SH varies interspecifically. In largemouth bass (Micropterus salmoides) and several clariid catfishes, the SH functions similarly to a stiff ligament. In these species, the SH remains isometric and transmitts power from the hypaxial musculature to the hyoid apparatus during suction feeding. Alternatively, the SH can shorten and contribute muscle power during suction feeding, a condition observed in the bluegill sunfish (Lepomis macrochirus) and one clariid catfish. An emerging hypothesis centers on SH muscle size as a predictor of function: in fishes with a large SH, the SH shortens during suction feeding, whereas in fish with a smaller SH, the muscle may remain isometric. Here, we studied striped surfperch (Embiotoca lateralis), a species in which the SH is relatively large at 8.8% of axial muscle mass compared with 4.0% for L. macrochirus and 1.7% for M. salmoides, to determine whether the SH shortens during suction feeding and is, therefore, bifunctional—both transmitting and generating power—or remains isometric and only transmits power. We measured skeletal kinematics of the neurocranium, urohyal, and cleithrum with Video Reconstruction of Moving Morphology, along with muscle strain and shortening velocity in the SH and epaxial muscles, using a new method of 3D external marker tracking. We found mean SH shortening during suction feeding strikes (n = 22 strikes from four individual E. lateralis) was 7.2 ± 0.55% (±SEM) of initial muscle length. Mean peak speed of shortening was 4.9 ± 0.65 lengths s−1, and maximum shortening speed occurred right around peak gape when peak power is generated in suction feeding. The cleithrum of E. lateralis retracts and depresses but the urohyal retracts and depresses even more, a strong indicator of a bifunctional SH capable of not only generating its own power but also transmitting hypaxial power to the hyoid. While power production in E. lateralis is still likely dominated by the axial musculature, since even the relatively large SH of E. lateralis is only 8.8% of axial muscle mass, the SH may contribute a meaningful amount of power given its continual shortening just prior to peak gape across all strikes. These results support the finding from other groups of fishes that a large SH muscle, relative to axial muscle mass, is likely to both generate and transmit power during suction feeding.

The FMRP-MOV10 complex: a translational regulatory switch modulated by G-Quadruplexes.

The Fragile X Mental Retardation Protein (FMRP) is an RNA binding protein that regulates translation and is required for normal cognition. FMRP upregulates and downregulates the activity of microRNA (miRNA)-mediated silencing in the 3′ UTR of a subset of mRNAs through its interaction with RNA helicase Moloney leukemia virus 10 (MOV10). This bi-functional role is modulated through RNA secondary structures known as G-Quadruplexes. We elucidated the mechanism of FMRP’s role in suppressing Argonaute (AGO) family members’ association with mRNAs by mapping the interacting domains of FMRP, MOV10 and AGO and then showed that the RGG box of FMRP protects a subset of co-bound mRNAs from AGO association. The N-terminus of MOV10 is required for this protection: its over-expression leads to increased levels of the endogenous proteins encoded by this co-bound subset of mRNAs. The N-terminus of MOV10 also leads to increased RGG box-dependent binding to the SC1 RNA G-Quadruplex and is required for outgrowth of neurites. Lastly, we showed that FMRP has a global role in miRNA-mediated translational regulation by recruiting AGO2 to a large subset of RNAs in mouse brain.

Glucose electrooxidation reaction in presence of dopamine and uric acid over ketjenblack carbon supported PdCo electrocatalyst

Herein, palladium-cobalt supported on ketjenblack (PCKB) electrocatalyst is synthesized and tested i) for the reaction of glucose electrooxidation (GOR) in presence of dopamine and uric acid and ii) for the simultaneous detection of the above three substances. The electrocatalyst, prepared using the sulphite complex method, is physicochemically characterized by X-Ray diffraction (XRD), transmission electron microscopy (TEM) and X-Ray photoelectron spectroscopy (XPS) and electrochemically characterized by cyclic voltammetry, potentiometry and chronoamperometry.It is found that the electrocatalytic activity towards GOR: i) is favoured in case of ketjenblack support, ii) is enhanced more when Co is added into Pd, iii) is enhanced with temperature increment from 26.0 to 42.0 °C, iv) is enhanced when glucose concentration increases up to 1.5 mM, while at higher concentration values is suppressed. The electrocatalyst ability of simultaneous glucose, dopamine and uric acid electrooxidation is attributed to the bi-functional role of the PCKB due to cobalt presence.

Bifunctional roles of Nd2O3 on improving the redox property of CeO2–ZrO2–Al2O3 materials

A series of Nd2O3 was introduced into CeO2–ZrO2–Al2O3(CZA) materials to improve their redox property, and then their soot oxidation activities were characterized. Although Nd2O3 incorporation obviously decreased the specific surface area, 7 wt% Nd2O3 modified CZA (fresh CZAN7) also exhibited the best activity, the temperature for 50% soot conversion (T50) over which is 25 °C lower than that over fresh CZA due to the more surface oxygen vacancies and the faster mobility of oxygen species. It indicates that redox property of CZA plays a critical role than specific surface area in determining the soot oxidation activity. Meanwhile, it is interesting that 31 °C lower of T50 is detected over the aged CZAN7 (1000 °C/4h) than its fresh counterpart (600 °C/3h). Combined with the results of Powder X-ray diffraction (XRD), High-resolution transmission electron microscope (HRTEM) and Raman, a new sight about the bifunctional roles of Nd2O3 on improving the redox property of CZA has been put forward. Nd2O3 could directly incorporate into CeO2–ZrO2 lattice to form CeO2–ZrO2-Nd2O3 solid solution. Meanwhile, it could also regulate the distribution of Zr species and promote them incorporate into CeO2–ZrO2 lattice during thermal treatment. Then CZAN7 could exhibit more surface oxygen species, increased surface oxygen vacancies and better soot oxidation activity even being thermally aged.