Compositional interplay of two different cobalt phosphates (Co(H2PO4)2; Co‐DP and Co(PO3)2; Co‐MP) loaded on morphologically engineered high surface area nanocarbon leads to an increased electrocatalytic efficiency for oxygen evolution reaction (OER) in near neutral conditions. This is reflected as significant reduction in the onset overpotential (301 mV) and enhanced current density (30 mA cm−2 @ 577 mV). In order to achieve uniform surface loading, organic‐soluble thermolabile cobalt‐bis(di‐tert‐butylphosphate) is synthesized in situ inside the nanocarbon matrix and subsequently pyrolyzed at 150 °C to produce Co(H2PO4)2/Co(PO3)2 (80:20 wt%). Annealing this sample at 200 or 250 °C results in the redistribution of the two phosphate systems to 55:45 or 20:80 (wt%), respectively. Detailed electrochemical measurements clearly establish that the 55:45 (wt%) sample prepared at 200 °C performs the best as a catalyst, owing to a relay mechanism that enhances the kinetics of the 4e− transfer OER process, which is substantiated by micro‐Raman spectroscopic studies. It is also unraveled that the engineered nanocarbon support simultaneously enhances the interfacial charge‐transfer pathway, resulting in the reduction of onset overpotential, compared to earlier investigated cobalt phosphate systems.
We put constraints on several products of R-parity violating λλ ′ and λ ′ λ ′ type couplings from leptonic and semileptonic τ , B d and B s decays. Most of them are one to two orders of magnitude better than the existing bounds, and almost free from theoretical uncertainties. A significant improvement of these bounds can be made in high luminosity tau-charm or B factories.
Haloferax mediterranei holds promise for competitive industrial-scale production of polyhydroxyalkanoate (PHA) because cheap carbon sources can be used thus lowering production costs. Although high salt concentration in production medium permits a non-sterile, low-cost process, salt disposal after process completion is a problem as current environmental standards do not allow total dissolved solids (TDS) above 2000 mg/l in discharge water. As the first objective of this work, the waste product of rice-based ethanol industry, stillage, was used for the production of PHA by H. mediterranei in shake flasks. Utilization of raw stillage led to 71 ± 2% (of dry cell weight) PHA accumulation and 16.42 ± 0.02 g/l PHA production. The product yield coefficient was 0.35 while 0.17 g/l h volumetric productivity was attained. Simultaneous reduction of BOD5 and COD values of stillage by 83% was accomplished. The PHA was isolated by osmotic lysis of cells, purification by sodium dodecyl sulfate and organic solvents. The biopolymer was identified as poly-3-(hydroxybutyrate-co-15.4 mol%-hydroxyvalerate) (PHBV). This first report on utilization of rice-based ethanol stillage for PHBV production by H. mediterranei is currently the most cost effective. As the second objective, directional properties of decanoic acid together with temperature dependence of water solubility in decanoic acid were applied for two-stage desalination of the spent stillage medium. We report for the first time, recovery and re-use of 96% of the medium salts for PHA production thus removing the major bottleneck in the potential application of H. mediterranei for industrial production of PHBV. Final discharge water had TDS content of 670 mg/l.
Under the conditions of this study, 2,3-dimercaptosuccinic acid was not effective in producing any clinical or biochemical benefit or any histopathological improvement of skin lesions in patients with chronic arsenicosis.
Upper bounds at the weak scale are put on all λ ′ ijk λ ′ imn type products of R-parity violating supersymmetry that may affect K 0 − K 0 and B 0 − B 0 mixing. We constrain all possible products, including some not considered before, using next-to-leading order QCD corrections to the mixing amplitudes. Constraints are obtained for both real and imaginary parts of the couplings. We also discuss briefly some correlated decay channels which should be investigated in future experiments.
Capacitors are the most practical high‐storage and rapid charge‐release devices. The number of ions stored per unit area and their interaction strength with the electrode dictates capacitor‐performance. Microporous materials provide a high storage surface and optimal interactions. Adsorbing electron‐rich and easily polarizable molecules into microporous electrodes is expected to boost Faradaic pseudo‐activity. If such electrode–electrolyte interactions can be made as a potential‐driven reversible process, the resulting capacitors would be adaptable and device‐friendly. A composite covalent organic framework (COF)‐carbon electrode with redox‐active KI is combined in an H2SO4 electrolyte for the first time. This composite electrode benefits from the redox‐functionality of COF and electronic conductivity of carbon, leading to superior capacitative activity. Operando spectro‐electrochemical measurements reveal the existence of multiple polyiodide species, although the I3− is the predominantly electroactive species adsorbing on the microporous triazine‐phenol COF electrode. A systematic fabrication of the flexible solid‐state devices using the COF‐redox‐electrolyte reveals a high areal capacitance of 270 ± 11 mF cm−2 and gravimetric capacitance of 57 ± 8 F g−1. The inclusion of KI in H2SO4 (electrolyte) yields an approximately eight‐fold enhancement in solid‐state gravimetric specific capacitance. The imine‐COF retains 89% of its capacity even after 10 000 cycles.
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