In this work, we report a highly efficient organic polymer nano-photocatalyst for light driven proton reduction. The system renders an initial rate of hydrogen evolution up to 50 plus or minus 0.5 ...mmol g-1 h-1, which is the fastest rate among all other reported organic photocatalysts. We also experimentally and theoretically prove that the nitrogen centre of the benzothiadiazole unit plays a crucial role in the photocatalysis and that the Pdots structure holds a close to ideal geometry to enhance the photocatalysis.
For the first time, organic semiconducting polymer dots (Pdots) based on poly(9,9′‐dioctylfluorenyl‐2,7‐diyl)‐co‐(1,4‐benzo‐{2,1′,3} thiadiazole) (PFBT) and polystyrene grafting with ...carboxyl‐group‐functionalized ethylene oxide (PS‐PEG‐COOH) are introduced as a photocatalyst towards visible‐light‐driven hydrogen generation in a completely organic solvent‐free system. With these organic Pdots as the photocatalyst, an impressive initial rate constant of 8.3 mmol h−1 g−1 was obtained for visible‐light‐driven hydrogen production, which is 5‐orders of magnitude higher than that of pristine PFBT polymer under the same catalytic conditions. Detailed kinetics studies suggest that the productive electron transfer quench of the excited state of Pdots by an electron donor is about 40 %. More importantly, we also found that the Pdots can tolerate oxygen during catalysis, which is crucial for further application of this material for light‐driven water splitting.
Organic polymer dots were used as a photocatalyst for visible‐light‐driven hydrogen generation for the first time and showed impressive activity with an initial hydrogen generation rate of 8.3 mmol h−1 g−1 without the assistance of any co‐catalysts. Do=donor.
The efficient conversion of light energy into chemical energy is key for sustainable human development. Several photocatalytic systems based on photovoltaic electrolysis have been used to produce ...hydrogen via water reduction. However, in such devices, light harvesting and proton reduction are carried separately, showing quantum efficiency of about 10-12%. Here, we report a nano-hybrid photocatalytic assembly that enables concomitant reductive hydrogen production and pollutant oxidation with solar-to-fuel efficiencies up to 20%. The modular architecture of this plasmonic material allows the fine-tuning of its photocatalytic properties by simple manipulation of a reduced number of basic components.
The objective of this study was to identify genomic regions that are associated with meat quality traits in the Nellore breed. Nellore steers were finished in feedlots and slaughtered at a commercial ...slaughterhouse. This analysis included 1,822 phenotypic records of tenderness and 1,873 marbling records. After quality control, 1,630 animals genotyped for tenderness, 1,633 animals genotyped for marbling, and 369,722 SNPs remained. The results are reported as the proportion of variance explained by windows of 150 adjacent SNPs. Only windows with largest effects were considered. The genomic regions were located on chromosomes 5, 15, 16 and 25 for marbling and on chromosomes 5, 7, 10, 14 and 21 for tenderness. These windows explained 3,89% and 3,80% of the additive genetic variance for marbling and tenderness, respectively. The genes associated with the traits are related to growth, muscle development and lipid metabolism. The study of these genes in Nellore cattle is the first step in the identification of causal mutations that will contribute to the genetic evaluation of the breed.
Hydrated electrons are important in radiation chemistry and charge-transfer reactions, with applications that include chemical damage of DNA, catalysis, and signaling. Conventionally, hydrated ...electrons are produced by pulsed radiolysis, sonolysis, two-ultraviolet-photon laser excitation of liquid water, or photodetachment of suitable electron donors. Here we report a method for the generation of hydrated electrons via single-visible-photon excitation of localized surface plasmon resonances (LSPRs) of supported sub-3 nm copper nanoparticles in contact with water. Only excitations at the LSPR maximum resulted in the formation of hydrated electrons, suggesting that plasmon excitation plays a crucial role in promoting electron transfer from the nanoparticle into the solution. The reactivity of the hydrated electrons was confirmed via proton reduction and concomitant H2 evolution in the presence of a Ru/TiO2 catalyst.
Understanding electron mobility on TiO
2
is crucial because of its applications in photocatalysis and solar cells. This work shows that shallow traps believed to be involved in electron migration in ...TiO
2
conduction band are formed upon band gap excitation,
i.e.
, are not pre-existing states. The shallow traps in TiO
2
results from large polarons and are not restricted to surface.
Understanding electron mobility on TiO
2
is crucial because of its applications in photocatalysis and solar cells.
In this work, the entropy based scaling laws of Rosenfeld, Dzugutov and Bretonnet, which connect reduced self-diffusion coefficients (D⁎) with residual entropy (named excess entropy in this field), ...were analysed in order to test their attributed universal character. With this purpose, an extensive database with 1727 molecular dynamic and experimental values was compiled for hard-sphere (HS), Lennard-Jones (LJ), hard-sphere chain (HSC), and real (polar, nonpolar, symmetrical and asymmetrical) fluids. It was shown that these equations fail when tested over the entire range of density and temperature (through residual entropy), even for atomic and simple fluids (e.g., HS and LJ) for which they have been originally proposed. Furthermore, the dependence of the self-diffusivities upon both residual entropy and a molecular chain length parameter (r) was clearly found on the basis of HSC and real data. Accordingly, a new universal correlation for the estimation of D⁎ as function of residual entropy and r was obtained, giving rise to an average absolute relative deviation of 9.13% for all database. It was also devised a very simple and accurate entropy based equation for spherical systems (HS and LJ) which provides only 4.61% of error. The original Rosenfeld, Dzugutov and Bretonnet's expressions attain deviations that are several orders of magnitude higher than our values.
► The self-diffusion coefficient (D11) is studied by entropy scaling law's approach. ► One shows that well know entropy scaling laws of the literature are not universal. ► One shows that D11 depends upon both residual entropy & chain length parameter. ► Universal D11 correlation is proposed for model & real fluids (9.13%, 1724 points). ► A simple equation is proposed specifically for HS and LJ fluids (4.61%, 659 points).
We report on the reactivity of grafted tantalum organometallic catalysts with molecular oxygen. The changes in the local Ta electronic structure were followed by
in situ
high-energy resolution ...off-resonant spectroscopy (HEROS). The results revealed agglomeration and formation of Ta dimers, which cannot be reversed. The process occurs independently of starting grafted complex.
We report on the reactivity of grafted tantalum organometallic catalysts with molecular oxygen.
A scalable and green procedure for the microfluidic flow synthesis of monodisperse silver nanoparticles is reported. Beetroot extract is used both as a reducing and growth-regulating agent. A ...multi-objective genetic algorithm was used to automate the optimization of the reaction and reduce sample polydispersity observed in previous reports. The proposed methodology ensures high-quality nanoparticles in a rapidly manner and devoid of human skill or intuition, essential for method standardization and implementation.
The objective of this study was to evaluate the accuracy of genomic predictions for rib eye area (REA), backfat thickness (BFT), and hot carcass weight (HCW) in Nellore beef cattle from Brazilian ...commercial herds using different prediction models.
Phenotypic data from 1756 Nellore steers from ten commercial herds in Brazil were used. Animals were offspring of 294 sires and 1546 dams, reared on pasture, feedlot finished, and slaughtered at approximately 2 years of age. All animals were genotyped using a 777k Illumina Bovine HD SNP chip. Accuracy of genomic predictions of breeding values was evaluated by using a 5-fold cross-validation scheme and considering three models: Bayesian ridge regression (BRR), Bayes C (BC) and Bayesian Lasso (BL), and two types of response variables: traditional estimated breeding value (EBV), and phenotype adjusted for fixed effects (Y*).
The prediction accuracies achieved with the BRR model were equal to 0.25 (BFT), 0.33 (HCW) and 0.36 (REA) when EBV was used as response variable, and 0.21 (BFT), 0.37 (HCW) and 0.46 (REA) when using Y*. Results obtained with the BC and BL models were similar. Accuracies increased for traits with a higher heritability, and using Y* instead of EBV as response variable resulted in higher accuracy when heritability was higher.
Our results indicate that the accuracy of genomic prediction of carcass traits in Nellore cattle is moderate to high. Prediction of genomic breeding values from adjusted phenotypes Y* was more accurate than from EBV, especially for highly heritable traits. The three models considered (BRR, BC and BL) led to similar predictive abilities and, thus, either one could be used to implement genomic prediction for carcass traits in Nellore cattle.
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