Boosting Up the Low Catalytic Activity of Silver for H2 Production on Ag/TiO2 Photocatalyst: Thiocyanate as a Selective Modifier

Noble metal cocatalysts like Pt have been widely employed as an essential ingredient in many kinds of photocatalytic materials for solar hydrogen production. The high material cost of Pt is the biggest limitation. Silver is far less expensive but much less active than Pt and Au as a hydrogen evolving catalyst. Here we demonstrate a new strategy to boost up the activity of silver in Ag/TiO2 for photocatalytic H-2 production via forming a simple surface complexation of thiocyanate (SCN-) on silver. The addition of thiocyanate in the suspension of Ag/TiO2 markedly enhanced the photocatalytic production of H-2 by about 4 times. Thiocyanate was not consumed at all during the photoreaction, which ruled out the role of thiocyanate as an electron donor. Such a positive role of thiocyanate was not observed with bare TiO2, Pt/TiO2, and Au/TiO2. The selective chemisorption of thiocyanate on silver was confirmed by the analyses of Raman spectroscopy and spot-profile energy-dispersive spectroscopy. In the presence of thiocyanate, the overpotential for water reduction on Ag/TiO2 electrode was slightly reduced, and the interfacial charge transfer resistance on Ag/TiO2 (measured by electrochemical impedance spectroscopy) was significantly decreased, whereas other electrode systems (bare TiO2, Au/TiO2, and Pt/TiO2) showed the opposite effect of thiocyanate. These results indicate that the adsorption of thiocyanate on Ag facilitates the transfer of photogenerated electrons on the Ag/TiO2 electrode. It is proposed that the formation of Ag-SCN surface complex enhances the interfacial electron transfer rate and facilitates the reduction of protons on Ag/TiO2.115640Ysciescopu

The co-injection of antioxidants with foot-and-mouth disease vaccination altered growth performance and blood parameters of finishing Holstein steers

Objective This study was conducted to evaluate whether the co-injection of antioxidants together with foot-and-mouth disease (FMD) vaccination has the potential to attenuate the negative effects caused by vaccination in Holstein finishing steers. Methods A total of 36 finishing Holstein steers (body weight [BW]: 608±45.6 kg, 17 months old) were randomly allocated to one of three treatments: i) control (CON, only FMD vaccination without any co-injection), ii) co-injection of commercial non-steroidal anti-inflammatory drugs (NSAID) with FMD vaccination at a ratio of 10:1 (NSAID vol/FMD vaccine vol) as a positive control (PCON), iii) co-injection of commercial mixture of vitamin E and selenium with FMD vaccination (VITESEL) (1 mL of FMD vaccine+1 mL of antioxidants per 90 kg of BW). Changes in growth performance and blood parameters because of treatments were determined. Results No significant difference in BW, average daily gain, and dry matter intake of the steers was observed among the treatments. The FMD vaccination significantly increased white blood cells (WBC), neutrophils, platelets, and mean platelet volume (p<0.01) in blood analysis. The count of lymphocyte tended to increase after vaccination (p = 0.08). In blood analysis, steers in VITESEL tended to have higher numbers of WBC, neutrophils, and platelets compared to that of other treatments (p = 0.09, 0.06, and 0.09, respectively). Eosinophils in VITESEL were higher than those in PCON (p<0.01). Among blood metabolites, blood urea nitrogen and aspartate transaminase were significantly increased, but cholesterol, alanine transferase, inorganic phosphorus, Mg, and albumin were decreased after FMD vaccination (p<0.01). Conclusion The use of antioxidants in FMD vaccination did not attenuate growth disturbance because of FMD vaccination. The metabolic changes induced by vaccination were not controlled by the administration of antioxidants. The protective function of antioxidants was effective mainly on the cell counts of leukocytes

Comparison of volatile organic compounds between cigarette smoke condensate (CSC) and extract (CSE) samples

Cigarette smoke is a major risk factor for several diseases, including chronic obstructive pulmonary and cardiovascular diseases. The toxicity of the cigarette smoke can be determined in vitro. The cytotoxicity test of the cigarette smoke is commonly conducted using the cigarette smoke condensate (CSC) and cigarette smoke extract (CSE). The CSC and CSE methods are well known for sampling of the particles and water-soluble compounds in the cigarette smoke, respectively. In this study, the CSC and CSE were analyzed by using a gas chromatography-mass spectrometry (GC-MS) system equipped with a wax column for separation of the volatile organic compounds. The cytotoxic effect of the CSC and CSE were evaluated thoroughly by comparing the analytical results of the CSC and CSE samples. The total concentration of the volatile organic compounds detected in the CSC sample was similar to that in the CSE sample based on the peak area. Except for the dimethyl sulfoxide solvent, nicotine had the highest concentration in the CSC sample, while acetonitrile had the highest concentration in the CSE sample. The compositions were as follows: (1) CSC sample: 55.8% nicotine, 18.0% nicotyrine, 3.20% 1,2,3-propanetriol, triacetate, 1.28% ethyl chloride, 1.22% phenol, etc. and (2) CSE sample: 18.7% acetonitrile, 18.0% acetone, 12.5% 2-hydroxy-2-methyl-propanenitrile, 8.98% nicotine, 5.86% nicotyrine, etc. In this manner, to accurately examine the cytotoxicity of the cigarette smoke using CSC or CSE, the components and their concentrations in the CSC and CSE samples should be considered

Enhanced hydrogen production from ammonia borane using controlled plasmonic performance of Au nanoparticles deposited on TiO2

Ammonia borane (AB) is a hydrogen storage material which can produce three equivalent moles of H-2 gas by a hydrolytic decomposition reaction in the presence of an appropriate catalyst. The photocatalytic H-2 generation from AB decomposition was studied by utilizing the Au/TiO2 plasmonic photocatalyst under both visible and UV light conditions. Different amounts of gold (0.5, 1, 2, and 3%) were photo-deposited on TiO2 (anatase) to prepare Au/TiO2 catalysts. Au(1 wt%)/TiO2 showed the highest activity of H-2 generation under visible light and a further increase of Au loading reduced the activity. Although LSPR (localized surface plasmon resonance) excitation should increase with gold nanoparticle (Au NP) loading, excessive Au loading also facilitates the recombination of LSPR charge pairs. The time-resolved photoluminescence (TRPL) decay spectra of Au/TiO2 clearly showed that the recombination rate of LSPR charge pairs is accelerated at higher Au loading. As a result, the photocatalytic activity of Au/TiO2 was optimized at 1 wt% Au loading to produce 88 mmol of H-2 in 4 h. However, such an optimized level of Au loading was not observed under UV light irradiation conditions and the UV photocatalytic production of H-2 increased with the Au loading up to 3% because higher Au loading facilitates the separation of charge pairs and accumulation of electrons in Au NPs through the Schottky barrier. These two different electron transfer behaviors (accumulation and recombination) can be further confirmed by the Cr(VI) reduction experiments since they showed a similar trend of photocatalytic activity with Au loading. This research provides a fundamental understanding for optimizing the photocatalytic activity of various metal-metal oxide heterojunction photocatalysts.118sciescopu

Effects of β-Mannanase and Bacteriophage Supplementation on Health and Growth Performance of Holstein Calves

The objective of this study was to evaluate the effects of dietary supplementation with bacteriophage and β-mannanase on health and growth performance in calves. Thirty-six pre-weaning male Holstein calves were randomly allocated to one of four dietary treatments with a 2 × 2 factorial arrangement: no supplementation, 0.1% β-mannanase, 0.1% bacteriophage, and both 0.1% bacteriophage and 0.1% β-mannanase supplementation in a starter on a dry matter basis. The experiment lasted from 2 weeks before weaning to 8 weeks after weaning. Twenty-two calves survived to the end of the experiment. No interaction was observed between the two different feed additives. The bacteriophage supplementation tended to increase the odds ratio of survival (p = 0.09). The number of Escherichia coli in feces significantly decreased by bacteriophage supplementation one week after weaning. β-mannanase supplementation increased the concentrate intake (p &lt; 0.01) and tended to increase the final BW (p = 0.08). Analysis of repeated measures indicated β-mannanase supplementation increased weekly body weight gain (p = 0.018). We conclude that bacteriophage supplementation may have a positive effect on calf survival rate, while β-mannanase supplementation may increase the growth rate and starter intake by calves just before and after weaning

Boosting up the Low Catalytic Activity of Silver for H₂ Production on Ag/TiO₂ Photocatalyst: Thiocyanate as a Selective Modifier

Noble metal cocatalysts like Pt have been widely employed as an essential ingredient in many kinds of photocatalytic materials for solar hydrogen production. The high material cost of Pt is the biggest limitation. Silver is far less expensive but much less active than Pt and Au as a hydrogen evolving catalyst. Here we demonstrate a new strategy to boost up the activity of silver in Ag/TiO₂ for photocatalytic H₂ production via forming a simple surface complexation of thiocyanate (SCN^–) on silver. The addition of thiocyanate in the suspension of Ag/TiO₂ markedly enhanced the photocatalytic production of H₂ by about 4 times. Thiocyanate was not consumed at all during the photoreaction, which ruled out the role of thiocyanate as an electron donor. Such a positive role of thiocyanate was not observed with bare TiO₂, Pt/TiO₂, and Au/TiO₂. The selective chemisorption of thiocyanate on silver was confirmed by the analyses of Raman spectroscopy and spot-profile energy-dispersive spectroscopy. In the presence of thiocyanate, the overpotential for water reduction on Ag/TiO₂ electrode was slightly reduced, and the interfacial charge transfer resistance on Ag/TiO₂ (measured by electrochemical impedance spectroscopy) was significantly decreased, whereas other electrode systems (bare TiO₂, Au/TiO₂, and Pt/TiO₂) showed the opposite effect of thiocyanate. These results indicate that the adsorption of thiocyanate on Ag facilitates the transfer of photogenerated electrons on the Ag/TiO₂ electrode. It is proposed that the formation of Ag-SCN surface complex enhances the interfacial electron transfer rate and facilitates the reduction of protons on Ag/TiO₂

Development of Novel Conjugated Polyelectrolytes as Water-Processable Interlayer Materials for High-Performance Organic Photodiodes

A series of novel conjugated polyelectrolytes composed of two different building blocks with different composition ratios were designed and synthesized for application as a functional layer in high-performance organic photodiodes (OPDs). A homopolymer and two random copolymers were prepared using different molar ratios of dibromo 1,4-bis­(4-sulfonatobutoxy)­benzene (SPh) and dibromo 1,4-bis­(4-tetraethylene glycol)­benzene (EGPh): <b>EG20</b> with SPh:EGPh ratio of 0.8:0.2 and <b>EG40</b> with a ratio of 0.6:0.4. Structural analyses by two-dimensional grazing-incidence X-ray diffraction and near-edge X-ray absorption fine structure spectroscopy studies proved that a higher EGPh content could induce more organized polymer chains with face-on orientation of <b>EG20</b> and <b>EG40</b>. Such an orientation of <b>EG20</b> and <b>EG40</b> along with the ordered crystalline organization yielded effective molecular dipole moments in the thin films when applied as an interlayer between ZnO and an active layer of inverted OPDs. As confirmed by ultraviolet photoelectron spectroscopy, the increase in EG content gradually shifted the workfunction of the ZnO, facilitating the inverted OPD to simultaneously achieve a decrease in dark current and enhancement in photocurrent. The synergetic effects introduced by the newly designed <b>EG20</b> and <b>EG40</b> resulted in significantly improved OPD performances with high specific detectivity up to 2.1 × 10¹³ Jones, 3 dB bandwidth of 72 kHz, and linear dynamic range of 110 dB