Exploring high‐efficiency and stable halide perovskite‐based photocatalysts for the selective reduction of CO2 to methane is a challenge because of the intrinsic photo‐ and chemical instability of ...halide perovskites. In this study, halide perovskites (Cs3Bi2Br9 and Cs2AgBiBr6) were grown in situ in mesoporous TiO2 frameworks for an efficient CO2 reduction. Benchmarked CH4 production rates of 32.9 and 24.2 μmol g−1 h−1 with selectivities of 88.7 % and 84.2 %, were achieved, respectively, which are better than most reported halide perovskite photocatalysts. Focused ion‐beam sliced‐imaging techniques were used to directly image the hyperdispersed perovskite nanodots confined in mesopores with tunable sizes ranging from 3.8 to 9.9 nm. In situ X‐ray photoelectronic spectroscopy and Kelvin probe force microscopy showed that the built‐in electric field between the perovskite nanodots and mesoporous titania channels efficiently promoted photo‐induced charge transfer. Density functional theory calculations indicate that the high methane selectivity was attributed to the Bi‐adsorption‐mediated hydrogenation of *CO to *HCO that dominates CO desorption.
Halide perovskites (Cs3Bi2Br9, Cs2AgBiBr6) are grown in situ in a mesoporous titania framework for efficient CO2 reduction reaction (CO2RR). A benchmarked production rate of CH4 (32.9 and 24.2 μmol g−1 h−1) is achieved with selectivity values of 88.7 % and 84.2 %, respectively. In situ X‐ray photoelectronic spectroscopy and Kelvin probe force microscopy reveal that the inner surface built‐in electric field between the perovskite nanodots and mesoporous titania channels can efficiently promote photo‐induced charge transfer.
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•Loofah sponge-derived 3D porous activated carbon is facilely prepared.•Hierarchical pores are constructed in the resulting SAC-x architecture.•SAC-4 exhibits excellent capacity ...performance in the three- and two-electrode systems.•The resulting materials have tremendous potentials for the energy storage applications.
Biomass carbon source is generally cheap, environmentally friendly and readily available in high quality and quantity. In this work, a series of loofah sponge-derived activated carbon (SAC-x) with hierarchical porous structures are prepared by KOH chemical activation and used as electrode materials for supercapacitors. The pore size can be easily controllable by changing the dosage of KOH. The optimized material (SAC-4) exhibits a high specific capacitance of 309.6Fg−1 at 1Ag−1 in the three-electrode system using 6M KOH electrolyte. More importantly, the as-assembled symmetric supercapacitor based on SAC-4 exhibits a high energy density of 16.1Whkg−1 at a power density of 160.0Wkg−1 using 1M Na2SO4 electrolyte. These remarkable results demonstrate the exciting commercial potential of SAC-x for high-performance supercapacitor applications due to their high specific surface area, appropriately porous structure, and the trace heteroatom (O and N) functionalities.
The combination of wastewater treatment and energy production is a hot issue that meets the current requirements of sustainable development. The direct discharge of large amounts of urea-rich ...wastewater without treatment will pose a serious threat to the environment and human health. Urea electrooxidation can realize wastewater restoration and transform energy at the same time. However, due to the 6e− transfer process of the urea oxidation reaction, the kinetics is sluggish, and exploring efficient catalysts for urea electrooxidation brooks no delay to improve. Nickel is considered to be an effective catalytic component of urea oxidation reaction, with low cost and good catalytic activity. This article reviews the recent research progress of nickel-based urea electrooxidation catalysts and makes a detailed comment on the four applications of wastewater remediation, hydrogen production, fuel cells, and urea sensors. Moreover, the development prospects and challenges faced by nickel-based catalysts and their practical applications are discussed.
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•Nickel is confirmed as an effective catalytic component for urea oxidation.•Various typical nickel-based catalysts in alkaline media are summarized.•The applications of nickel-based catalysts in urea oxidation are introduced.
Although plasma corticosterone is considered the main glucocorticoid involved in regulation of stress responses in rodents, the presence of plasma cortisol and whether its level can be used as an ...indicator for rodent activation of stress remain to be determined. In this study, effects of estrous cycle stage, circadian rhythm, and acute and chronic (repeated or unpredictable) stressors of various severities on dynamics and correlation of serum cortisol and corticosterone were examined in mice. A strong (r = 0.6-0.85) correlation between serum cortisol and corticosterone was observed throughout the estrous cycle, all day long, and during acute or repeated restraints, chronic unpredictable stress and acute forced swimming or heat stress. Both hormones increased to the highest level on day 1 of repeated-restraint or unpredictable stresses, but after that, whereas the concentration of cortisol did not change, that of corticosterone showed different dynamics. Thus, whereas corticosterone declined dramatically during repeated restraints, it remained at the high level during unpredictable stress. During forced swimming or heat stress, whereas cortisol increased to the highest level within 3 min., corticosterone did not reach maximum until 40 min. of stress. Analysis with HPLC and HPLC-MS further confirmed the presence of cortisol in mouse serum. Taken together, results (i) confirmed the presence of cortisol in mouse serum and (ii) suggested that mouse serum cortisol and corticosterone are closely correlated in dynamics under different physiological or stressful conditions, but, whereas corticosterone was a more adaptation-related biomarker than cortisol during chronic stress, cortisol was a quicker responder than corticosterone during severe acute stress.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A built‐in electric field in electrocatalyst can significantly accumulate higher concentration of NO3− ions near electrocatalyst surface region, thus facilitating mass transfer for efficient nitrate ...removal at ultra‐low concentration and electroreduction reaction (NO3RR). A model electrocatalyst is created by stacking CuCl (111) and rutile TiO2 (110) layers together, in which a built‐in electric field induced from the electron transfer from TiO2 to CuCl (CuCl_BEF) is successfully formed . This built‐in electric field effectively triggers interfacial accumulation of NO3− ions around the electrocatalyst. The electric field also raises the energy of key reaction intermediate *NO to lower the energy barrier of the rate determining step. A NH3 product selectivity of 98.6 %, a low NO2− production of <0.6 %, and mass‐specific ammonia production rate of 64.4 h−1 is achieved, which are all the best among studies reported at 100 mg L−1 of nitrate concentration to date.
An electrocatalyst is created by stacking CuCl (111) and rutile TiO2 (110) layers together. A built‐in electric field induced from the electron transfer from TiO2 to CuCl (CuCl_BEF) is thus formed, which triggers interfacial accumulation of NO3− ions around the electrocatalyst. A NH3 product selectivity of 98.6 %, a low NO2− production of <0.6 %, and mass‐specific ammonia production rate of 64.4 h−1 is achieved.
Nitrate electrocatalytic reduction (NO3RR) for ammonia production is a promising strategy to close the N‐cycle from nitration contamination, as well as an alternative to the Haber–Bosch process with ...less energy consumption and carbon dioxide release. However, current long‐term stability of NO3RR catalysts is usually tens of hours, far from the requirements for industrialization. Here, symmetry‐broken Cusingle‐atom catalysts are designed, and the catalytic activity is retained after operation for more than 2000 h, while an average ammonia production rate of 27.84 mg h−1 cm−2 at an industrial level current density of 366 mA cm−2 is achieved, obtaining a good balance between catalytic activity and long‐term stability. Coordination symmetry breaking is achieved by embedding one Cu atom in graphene nanosheets with two N and two O atoms in the cis‐configuration, effectively lowering the coordination symmetry, rendering the active site more polar, and accumulating more NO3− near the electrocatalyst surface. Additionally, the cis‐coordination splits the Cu 3d orbitals, which generates an orbital‐symmetry‐matched π‐complex of the key intermediate *ONH and reduces the energy barrier, compared with the σ‐complex generated with other catalysts. These results reveal the critical role of coordination symmetry in single‐atom catalysts, prompting the design of more coordination‐symmetry‐broken electrocatalysts toward possible industrialization.
A coordination‐symmetry‐breaking Cusingle‐atom catalyst enables a good balance between catalytic activity and long‐term stability in nitrate electroreduction to ammonia. The catalytic activity is retained after operation for more than 2000 h, while an average ammonia production rate of 27.84 mg h−1 cm−2 at an industrial level current density of 366 mA cm−2 is achieved.
The aim of this study was to investigate the prevalence of sleep problems, depression and anxiety symptoms among conscripted frontline nurses fighting coronavirus disease 2019 (COVID-19) in ...Wuhan.This study was a cross-sectional study conducted with 100 frontline nurses. Sleep quality, depression, and anxiety symptoms were measured using the Pittsburgh sleep quality index (PSQI), the Generalized Anxiety Disorder 7-Item Scale (GAD-7) and the Patient Health Questionnaire-9 (PHQ-9), respectively.Mean sleep duration was 5.71 hours (SD = 1.09) and mean sleep latency was 33.49 minutes (SD = 28.87). A total of 76%, 81%, 45%, and 19% reported difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS) or early morning awakening (EMA), nightmares and using hypnotics respectively. Among 100 participants in this study, 60 (60%) had poor sleep quality, 46 (46%) suffered depression symptoms and 40 (40%) reported anxiety symptoms. Sleep quality (OR = 3.16, 95% CI: 1.17-8.52) and anxiety symptoms (OR = 8.07, 95% CI: 2.92-22.33) were significantly associated with depression symptoms. Depression symptoms (OR = 7.92, 95% CI: 2.89-21.73) were related to anxiety symptoms. Similarly, depression symptoms (OR = 3.24, 95% CI: 1.19-8.79) were associated with poor sleep quality.Sleep disturbance, depression, and anxiety symptoms are very common among frontline nurses who treating patients with COVID-19 in Wuhan, China. Comprehensive measures that involve psychosocial and personal behaviors should be implemented to improve sleep quality and prevent depression and anxiety symptoms.
In this work, gliadin/sodium carboxymethyl cellulose nanoparticles (G/CMC) were prepared to encapsulate bioactive phloretin (Phl) for improving the stability and bioaccessibility by simple ...antisolvent precipitation. Scanning electron microscopy (SEM) and dynamic light scattering showed that G/CMC nanoparticles were spherical with the diameter below 350 nm. Electrostatic interaction and hydrogen bond were dominant driving force during the formation of G/CMC nanoparticles. Phloretin-loaded G/CMC nanoparticles (G/CMC-Phl) had robust resistance to pH shift, heat treatment and UV irradiation. The bioaccessibility of encapsulated phloretin increased from 23% to 55% via the strategy, as compared with free phloretin. Meanwhile, G/CMC-Phl had a strongly protective effect on erythrocyte hemolysis induced by 2, 2′-azobis-2-methyl-propanimidamide dihydrochloride (AAPH), and inhibited the generation of reactive oxygen species (ROS). It could recover the intracellular antioxidant enzymes (superoxide dismutase, SOD and glutathione peroxidase, GSH-Px) activity to normal levels and inhibit the production of malondialdehyde (MDA). Moreover, the protection and control release behavior of G/CMC nanoparticles was investigated by B16 mouse melanoma cells. This study provides a simple way to fabricate food-grade nanoparticles for the encapsulation of water-insoluble phloretin to broaden the application in pharmaceutical, cosmetics and food industry.
A schematic representation of the G/CMC-Phl nanoparticles. Display omitted
•Gliadin and CMC composite nanoparticles (G/CMC) were successfully prepared.•G/CMC nanoparticles had high encapsulation efficiency for phloretin.•G/CMC nanoparticles improved the stability and bioacessibility of phloretin.•Phloretin loaded G/CMC nanoparticles (G/CMC-Phl) had strong intracellular antioxidant activity.
Memristors are emerging as a rising star of new computing and information storage techniques. However, the practical applications are severely challenged by their instability toward harsh conditions, ...including high moisture, high temperatures, fire, ionizing irradiation, and mechanical bending. In this work, for the first time, lead‐free double perovskite Cs2AgBiBr6 is utilized for environmentally robust memristors, enabling highly efficient information storage. The memory performance of the typical indium‐tin‐oxide/Cs2AgBiBr6/Au sandwich‐like memristors is retained after 1000 switching cycles, 105 s of reading, and 104 times of mechanical bending, comparable to other halide perovskite memristors. Most importantly, the memristive behavior remains robust in harsh environments, including humidity up to 80%, temperatures as high as 453 K, an alcohol burner flame for 10 s, and 60Co γ‐ray irradiation for a dosage of 5 × 105 rad (SI), which is not achieved by any other memristors and commercial flash memory techniques. The realization of an environmentally robust memristor from Cs2AgBiBr6 with a high memory performance will inspire further development of robust electronics using lead‐free double perovskites.
Double perovskite Cs2AgBiBr6 is fabricated into an indium tin oxide/Cs2AgBiBr6/Au device for the first time. Ultrastable memristive behavior is obtained owing to the tough crystallinity of Cs2AgBiBr6. Humidity‐, high temperature‐, fire‐, and radiation‐resistant properties of Cs2AgBiBr6‐based devices promote memristive devices to work in harsh environments, where most perovskite‐based devices may fail to work.
•We summarized and discussed about As in drinking water for all territories in China.•Possible natural As sources in drinking water, were documented.•Typical environmental conditions for occurrence ...of geogenic high-As waters.•Anthropogenic As contaminations in China were summarized.
Chronic endemic arsenicosis areas have been discovered in China since 1960s. Up to 2012, 19 provinces had been found to have As concentration in drinking water exceeding the standard level (0.05mg/L). Inner Mongolia, Xinjiang and Shanxi Province are historical well-known “hotspots” of geogenic As-contaminated drinking water. The goal of this review is to examine, summarize and discuss the information of As in drinking water for all provinces and territories in China. Possible natural As sources for elevating As level in drinking water, were documented. Geogenic As-contaminated drinking water examples were taken to introduce typical environmental conditions where the problems occurred: closed basins in arid or semi-arid areas and reducing aquifers under high pH conditions. Geothermal water or mineral water in mountains areas can be high-As water as well. For undiscovered areas, prediction of potential As-affected groundwater has been carried out by some research groups by use of logistic regression. Modeled maps of probability of geogenic As contamination in groundwater are promising to be used as references to discover unknown areas. Furthermore, anthropogenic As contaminations were summarized and mining, smelters and chemical industries were found to be major sources for As pollution in China.
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