A Graphene Based–biomimetic Molecularly Imprinted Polyaniline Sensor for Ultrasensitive Detection of Human Cardiac Troponin T(cTnT)

In the present work, a biomimetic nano-molecularly imprinted polymer (N-MIP) electrode based on a graphene screen-printed electrode was developed for the ultrasensitive detection of cardiac troponin T (cTnT). The biomimetic cavities for targeted sensing for analyte were fabricated by the electropolymerization of conductive co-polymer matrix of aniline and carboxylated aniline on the graphene oxide (GO) electrode, in the presence template protein (cTnT for cardiac troponin T probe) by cyclic voltammetry. The surface characterization of the sensor was performed using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), and scanning electron microscopy (SEM). The best biomimetic surface nanotexture was obtained at aniline/carboxylatedaniline ratio of 1:4. The linear range of cTnT probe was in the range of 0.02 to 0.09 ng/mL, with the detection limit of 0.008 ng/mL. The reliability of the N-MIP cTnT sensor was examined by comparing the results with those obtained from HPLC method, and it was observed that the results from N-MIP sensors and HPLC have a great correlation

ZnO quantum dots-graphene composites: Formation mechanism and enhanced photocatalytic activity for degradation of methyl orange dye

The current study demonstrates homogenous decorating of zinc oxide quantum dots (QDs) onto graphene oxide (GO) surface via simple chemical method. The AFM image exhibited that the prepared graphene was 0.8 nm thick and hence practically monolayer. Average size of the ZnO QDs was estimated by transmission electron microscopy around 3 nm. Instrumental and chemical analyses demonstrated formation of a strong bond between ZnO QDs and GO, through C-O-Zn and C-Zn bridges. The UV-visible spectra displayed that the introduction of graphene sheets to ZnO QDs resulted in higher absorption intensity of UV as well as widening of adsorption window toward visible light for ZnO-Graphene due to chemical bond between ZnO QDS and graphene surface. Results showed that adding of graphene up to 30% can improve resistance of ZnO against acids however for keeping the activity of catalyst, the recommended pH is near neutral (pH approximate to 6-7.2). In addition, the presence of graphene on the surface of the ZnO could significantly suppress the photocorrosion effect. The ZnO-Graphene hybrids indicated enhanced photocatalytic activity for degradation of methyl orange (MO) with the following order: ZnO-5% Graphene > ZnO-10% Graphene > ZnO QDs > ZnO30%-Graphene. This enhancement of photocatalytic activity may be attributed to the extended absorption of visible light, reducing of electronehole recombination rate, and adsorption of MO molecules onto the huge surface area of graphene, where they are kept at vicinity of ZnO for decomposition. (C) 2015 Elsevier B.V. All rights reserved

Optimal growth of sodium titanate nanoflower on TiO2 thin film for the fabrication of a novel Ti/TiO2/Na2Ti3O7 photoanode with excellent stability

This study reports the effect of the Ti source (Ti foil or TiO2 thin layer) and NaOH concentration on the growth of sodium titanate nanostructures via hydrothermal treatment to improve the photoelectrochemical (PEC) water splitting performance. An optimal condition to grow sodium titanate nanoflower composed of ultrathin nanosheets on the surface of the thin TiO2 film led to the formation of a novel nanocomposite TiO2/Na2Ti3O7 photoelectrode with great adhesion of the two phases. The Ti/TiO2/Na2Ti3O7 photoanode demonstrated a significant enhancement in photocurrent density and shifted the onset potential to a more negative value compared to the pure Ti/TiO2 and Ti/Na2Ti3O7 samples. This noticeable improvement is attributed to the suitable band alignment between the TiO2 and Na2Ti3O7 phases and their direct contact with the Ti foil, as well as the large surface area of nanoflower sodium titanate, which significantly facilitate the generation, separation, and transfer of photogenerated electrons from the active phases to the substrate. More interestingly, the prepared photoanode retained its initial photocurrent density even after 16 h. An ion-exchange method and calcination treatment were used at different temperatures to convert the Na2Ti3O7 phase in the Ti/TiO2/Na2Ti3O7 photoanode to TiO2 to investigate the role of type II heterojunction for efficient photogenerated charge carrier separation in this photoanode. It was concluded that converting Na2Ti3O7 into TiO2 in the Ti/TiO2/Na2Ti3O7 system would reduce its PEC performance due to the formation of a pure phase of TiO2 in the Ti/TiO2/TiO2 photoanode

Photoelectrochemical Performance of a CuBi₂O₄ Photocathode with H₂O₂ as a Scavenger

Photoelectrochemical (PEC) water splitting is an eco-friendly method for producing clean and sustainable hydrogen fuels. Compared with the fabrication of solar hydrogen using n-type metal oxide semiconductor photoanodes, that of solar hydrogen using p-type metal oxide semiconductor photocathodes has not been researched as thoroughly. Therefore, this study investigated the effect of drop casting time on the PEC performance of a prepared CuBi2O4 photocathode. XPS, HRTEM, UV-DRS, Raman spectroscopy, XRD, and SEM analyses were used to characterize the prepared CuBi2O4 photocathode. Owing to the high charge separation and transfer, the photocurrent density of the CuBi2O4 photocathode was ~0.6 mA cm−2 at 0.3 V vs. RHE. The nanoporous CuBi2O4 photocathode exhibited a high photocurrent density of up to 1.2 mA cm−2 at 0.3 V vs. RHE with H2O2 as a sacrificial agent. Mott–Schottky and impedance measurements were also performed on the CuBi2O4 photocathode to estimate its acceptor density and charge-transfer resistance

Highly efficient and stable WO3/MoS2-MoOX photoanode for photoelectrochemical hydrogen production; a collaborative approach of facet engineering and P-N junction

In this paper, we demonstrate a facet-controlled WO3 nanoplate heterojunction with MoS2-MoOX nanosheets that produces extremely efficient and stable photoelectrochemical H-2 production. Furthermore, the effect of the hydrothermal process time (t = 1, 2, and 3 h) for the WO3 photoanode and drop-casting process of the MoS2 nanosheets (4, 8, and 12 times) to obtain the optimum amount of the material (MoS2 and MoOX) for the PEC performance of the WO3/#n-MoS2 and WO3/#n-MoS2-MoOX (n = 4, 8, and 12) photoanodes were investigated. The photocurrent density of the WO3/MoS2-MoOX photoanode was approximately 2.15 mA.cm(2) at 1.23 V vs. RHE, which was 8.6 and 1.2 times higher compare to pure WO3 and WO3/MoS2 photoelectrodes, respectively. The incident photon current efficiency of the WO3/MoS2-MoOX photoanode is approximately 27.5%, which is a significant improvement over that of bare WO3. The WO3/MoS2-MoOX photoanode produced 54.5 mu molcm(-2) of H-2 and 25.8 mu molcm(-2) of O-2 after 2 h, at 1.23 V vs. RHE and 100 mWcm(-2). The electrochemical kinetics clearly showed that water oxidation reaction was accelerated. The WO3/MoS2-MoOX photoanode, which was developed through simple and facial drop casting of MoS2 nanosheets onto WO3 photoanode, resulted in effective photo-generated carrier separation and enhanced oxygen evolution reactions on the anode surface

Electrocatalytic Reactions for Converting CO₂ to Value-Added Products: Recent Progress and Emerging Trends

Carbon dioxide (CO2) emissions are an important environmental issue that causes greenhouse and climate change effects on the earth. Nowadays, CO2 has various conversion methods to be a potential carbon resource, such as photocatalytic, electrocatalytic, and photo-electrocatalytic. CO2 conversion into value-added products has many advantages, including facile control of the reaction rate by adjusting the applied voltage and minimal environmental pollution. The development of efficient electrocatalysts and improving their viability with appropriate reactor designs is essential for the commercialization of this environmentally friendly method. In addition, microbial electrosynthesis which utilizes an electroactive bio-film electrode as a catalyst can be considered as another option to reduce CO2. This review highlights the methods which can contribute to the increase in efficiency of carbon dioxide reduction (CO2R) processes through electrode structure with the introduction of various electrolytes such as ionic liquid, sulfate, and bicarbonate electrolytes, with the control of pH and with the control of the operating pressure and temperature of the electrolyzer. It also presents the research status, a fundamental understanding of carbon dioxide reduction reaction (CO2RR) mechanisms, the development of electrochemical CO2R technologies, and challenges and opportunities for future research

Barriers standards of professional ethics in clinical care from the perspective of nurses

Promoting professional values is an importantfactor in the development of nursing careers, so anymischief in honoring professional commitment and ethicscan overcome the quality of nursing care. The view ofmost nurses is there are barriers to ethical performancein their work environment, which disrupts their ability toprovide appropriate care. According to the above, andsuch a study was not carried out in Bam, this study aimedto determine Barriers standards of professional ethics inclinical care from the perspective of nurses. Methods: Thisdescriptive-analytic study was conducted with the participationof nurses of Bam Pasteur Hospital in a census sampling.Tool for collecting information is a questionnairethat examines the barriers to observing professional ethicsstandards in three dimensions: managerial, environmentaland individual-care. Data were analyzed by SPSS softwareversion 23 using descriptive statistics (frequency, mean,standard deviation) and inferential statistics (independentt-test, ANOVA). The results of the study showed that thereis no significant relationship between observance of ethicalcriteria and demographic variables. The mean barriersstandards of professional ethics in clinical care from theperspective of nurses was 0/56±3/81 that according tothe maximum mean (5), There are barriers to standardsof professional ethics in clinical care, which has averagebarriers in various fields as follows: environmental barrierswith an average of 0/66±4/10, administrative barrierswith an average of 0/64±3/77 and personal barriers withan average of 0/65±3/75, respectively. Discussion: Consideringthat environmental factors are known as the mostimportant barrier to non-observance of professional ethicsstandards, Therefore, it is suggested that health carecenters with careful planning and emphasis on principlesand standards of care, including environmental factors,The importance of professional ethics in improving patients’Disadvantages of non-compliance with professionalethics, Providing favorable conditions for nurses suchas improving the conditions of the wards, Creating a safeand secure physical and psychological environment andmeeting their needs, such as rest and adequate income,Arrangement of appropriate shifts, provision of standardequipment, Take effective steps to comply with the beststandards of professional ethics

Simultaneous Enhancement of Charge Separation and Hole Transportation in a W:alpha-Fe2O3/MoS2 Photoanode: A Collaborative Approach of MoS2 as a Heterojunction and W as a Metal Dopant

In this study, a facile approach has been successfully applied to synthesize a W-doped Fe2O3/MoS2 core-shell electrode with unique nanostructure modifications for photoelectrochemical performance. A two-dimensional (2D) structure of molybdenum disulfide (MoS2) and tungsten (W)-doped hematite (W:alpha-Fe2O3) overcomes the drawbacks of the a-Fe2O3 and MoS2 semiconductor through simple and facile processes to improve the photoelectrochemical (PEC) performance. The highest photocurrent density of the 0.5W:alpha-Fe2O3/MoS2 photoanode is 1.83 mA.cm(-2) at 1.23 V vs reversible hydrogen electrode (RHE) under 100 mW.cm(2) illumination, which is higher than those of 0.5W:alpha-Fe2O3 and pure alpha-Fe2O3 electrodes. The overall water splitting was evaluated by measuring the H-2 and O-2 evolution, which after 2 h of irradiation for 0.5W:alpha-Fe2O3/MoS2 was determined to be 49 and 23.8 mu mol.cm(-2), respectively. The optimized combination of the heterojunction and metal doping on pure alpha-Fe2O3 (0.5W:alpha-Fe2O3/MoS2 photoanode) showed an incident photon-to-electron conversion efficiency (IPCE) of 37% and an applied bias photon-to-current efficiency (ABPE) of 26%, which are around 5.2 and 13 times higher than those of 0.5W:alpha-Fe2O3, respectively. Moreover, the facile fabrication strategy can be easily extended to design other oxide/carbon-sulfide/oxide core-shell materials for extensive applications