نتایج جستجو برای: alkaline media
تعداد نتایج: 321475 فیلتر نتایج به سال:
Oxygen reduction is considered a key reaction for electrochemical energy conversion but slow kinetics hamper application in fuel cells and metal-air batteries. In this review, the prospect of perovskite oxides for the oxygen reduction reaction (ORR) in alkaline media is reviewed with respect to fundamental insight into activity and possible mechanisms. For gaining these insights, special emphas...
Au-TiO2 nanocomposites were prepared by chemical deposition of gold nanoparticles onto TiO2 nanocolloids that were synthesized by a hydrothermal method. Transmission electron microscopic measurements showed that the TiO2 colloids exhibited an average diameter of about 5 nm and clearly defined lattice fringes that were consistent with those of anatase TiO2 and formed rather large agglomerates th...
The oxygen reduction reaction (ORR) in 0.1 M NaOH on platinum single crystal electrodes has been studied using hanging meniscus rotating disk electrode configuration. Basal planes and stepped surfaces with (111) and (100) terraces have been employed. The results indicate that the Pt(111) electrode has the highest electrocatalytic activity among all the studied surfaces. The addition of steps on...
Electrochemical techniques, coupled with in situ scanning tunneling microscopy, have been used to examine the mechanism of CO oxidation and the role of surface structure in promoting CO oxidation on well-ordered and disordered Pt(111) in aqueous NaOH solutions. Oxidation of CO occurs in two distinct potential regions: the prepeak (0.25-0.70 V) and the main peak (0.70 V and higher). The mechanis...
The ability to grow in a medium at pH 9.6 was one of the tolerance tests suggested by Sherman and Stark (1934) for the identification of Streptococcus faecalis. Subsequent investigations have indicated that the ability to grow at this high pH is a general characteristic of the enterococcus group with the exception of some strains of Streptococcus durans (Smith and Sherman, 1938; Shattock and Hi...
A study was made to find out maximum partitioning of Bacillus licheniformis alkaline phosphatase in different ATPSs composed of different molecular weight of PEG X (X=2000, 4000, 6000) with salts (magnesium sulphate, sodium sulphate, sodium citrate) and polymers (dextran 40, dextran T500). Physicochemical factors such as effect of system pH, system temperature and production media were evaluate...
The influence of the pH on the persistence of four neonicotinoid insecticides: imidacloprid, thiamethoxam, acetamiprid and thiacloprid, was studied by H NMR spectrometry at different pH values of Britton-Robinson buffers (4.0, 7.0 and 9.0) at a constant temeprature. Thiamethoxam and imidacloprid, having an identical nitroguanidine functional group, exhibited low persistence in alkaline media, a...
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