Retention of anions in cobalt hydroxide with Ni substitution to emphasize the role of anions and cations for high current density in oxygen evolution reactions

2020 ◽  
Vol 49 (46) ◽  
pp. 16962-16969
Author(s):  
Umair Shamraiz ◽  
Rukhsana Gul ◽  
Amin Badshah ◽  
Bareera Raza

Herein, we report the fabrication of remarkably fine nickel-substituted α-Co(OH)2 sheets using an ingenious co-precipitation method at a lower pH value.

2020 ◽  
Vol 7 (19) ◽  
pp. 3627-3635 ◽  
Author(s):  
Rui Guo ◽  
Yan He ◽  
Renchao Wang ◽  
Junhua You ◽  
Hongji Lin ◽  
...  

It is increasingly important to develop an efficient OER catalyst that can provide high current density at low overpotentials to improve water splitting efficiency.


2015 ◽  
Vol 1094 ◽  
pp. 15-19
Author(s):  
Lin Xia Yan ◽  
Sen Lin Tian ◽  
Qiu Lin Zhang

Cu-Al catalysts were synthesized by the co-precipitation method to study hydrolysis of hydrogen cyanide. During the synthesis, the impact of Cu/Al molar ratio, pH value and calcination temperature was investigated and the best synthesis condition was found. The results indicate that the remove of hydrogen cyanide first increases and then decreases with increasing Cu/Al molar ratio, pH value and calcination temperature, which reaches the maxima and remains above 95% at 360 min when Cu/Al molar ratio is 2:1, pH value is approximately 8.0 and calcination temperature is 400°C around. The analysis of X-ray diffraction (XRD) shows that Cu content is the main influence factor at Cu/Al molar ratio below 2:1 whereas crystallinity of catalysts is the key factor at Cu/Al molar ratio above 2:1.


2013 ◽  
Vol 756 ◽  
pp. 74-79 ◽  
Author(s):  
Bashiru Kayode Sodipo ◽  
Azlan Abdul Aziz

Superparamagnetic iron oxide nanoparticles (SPION) of sizes 5 to10 nm were synthesized by the co-precipitation method. They are coated with silica nanoparticles using sonication method. The SPION was produced under the optimum pH of 10, peptized in acidic medium and redispersed in water. The silica nanoparticles were produced through the Stöbermethod. Sonochemical coating of silica nanoparticle on the SPION was successfulat a pH value lower than 5. Otherwise, at higher pH value (but lower than point zero charge (PZC)), the SPION were found to be unstable. Fast hydrolysis of triethoxyvinylsilane(TEVS) shows that silica forms its own particles without coating onto the surfaces of the SPION. Under optimized experimental condition, sonochemical method of coating silica nanoparticles onto the SPION can be considered as an alternative for effective and prompt method that rely mainly on pH of the suspension.


2016 ◽  
Vol 30 (5) ◽  
pp. 1177-1186 ◽  
Author(s):  
Safia Anjum ◽  
Hafsa Saleem ◽  
Khalid Rasheed ◽  
Rehana Zia ◽  
Saira Riaz ◽  
...  

2016 ◽  
Vol 6 (23) ◽  
pp. 8222-8233 ◽  
Author(s):  
Yujie Xie ◽  
Yun Guo ◽  
Yanglong Guo ◽  
Li Wang ◽  
Wangcheng Zhan ◽  
...  

The La0.4–MnOx catalyst prepared by using the co-precipitation method exhibited excellent activity and thermal stability for propane deep oxidation.


2011 ◽  
Vol 236-238 ◽  
pp. 2076-2079
Author(s):  
Yan Rong Sun ◽  
Tao Fan ◽  
Yong Huang ◽  
Li Guo Ma ◽  
Feng Liu

The introduction of biomineralization was coupled with the co-precipitation synthesis process of nano-hydroxyapatite with the addition of chondroitin sulfate as a template agent. The effect of a variety of processing conditions on the properties of final hydroxyapatite (HA) product was investigated by orthogonal design. The ratio of calcium to phosphorus was detected by chemical analysis, the phase composition was evaluated by X-ray diffraction (XRD), and the powder morphology was characterized by transmission electron microscope (TEM). The process scheme, moreover, was optimized by the analysis of four aspects which may have different extent of influence on product properties. It can be concluded from the results that product properties can be affected remarkably by the content of chondroitin sulfate and the pH value of reactant, less remarkably by the reaction temperature and slightly by the reaction time.


2021 ◽  
Author(s):  
shumin wang ◽  
Ao Guan ◽  
Jiahan Wang ◽  
Xiaofang Fu ◽  
Xiang Guo ◽  
...  

Abstract Manganese dioxide (α-MnO2) nanorods with diameters of about 5-15 nm and lengths of 100-150 nm were synthesized by a simple co-precipitation method. XRD, TEM, HRTEM, SAED and XPS were used to analyze the crystallographic information, microstructure and chemical bonding of the as-prepared sample. The α-MnO2 nanorod exhibited a high efficiency and rapid removal rate of rhodamine B (RhB), which reached about 97.5% within 10 min when pH=4 (and pH=6.6) and 97.7% within 50 min when pH = 9 in the presence of H2O2. The results also indicated that a lower pH value is conducive to the movement of the characteristic peak and the attenuation of the intensity of the characteristic peak of RhB dye. Then a possible catalytic mechanism was revealed. Moreover, the α-MnO2 nanorod exhibits an excellent recyclability and catalytic stability. This research indicates that α-MnO2 nanorods have a potential application in practical dye pollutant treatment.


Author(s):  
O. Nikiforova ◽  
M. Delva

Migraine is one of the most common primary headaches, caused by functional abnormalities of information processing, which can be investigated by neurophysiological means during the various phases of the migraine cycle. The aim of the work was to study neurophysiological changes by means of nociception-specific blink reflex characteristics of trigeminocervical complex and to compare neuro-physiological data with clinical manifestations during various phases of episodic migraine. Methods. A 24-year old female patient with episodic migraine without aura underwent daily nociceptive stimulation of the trigeminal nerve for 30 days. Clinical data were collected directly from the patient using structured questionnaires. Neurophysiological changes were assessed using electromyography study of trigeminocervical blink reflex that was caused by stimulation of the supraorbital nerve with high current density electrode. Results. Within one month, the patient had two migraine attacks, preceded by the prodromal phase, and at the end of both migraine attacks, postdrome symptoms were present. We observed cyclical changes in the characteristics of component R2 of the nociception-specific blink reflex that coincided with clinical manifestations in different phases of the migraine cycle. Conclusions. 1. Electrophysiological excitability of trigeminocervical complex nociceptors differs significantly during different phases of the migraine cycle. 2. The habituation of component R2 is observed in the period between attacks can be considered as a specific phenomenon that probably is the background for migraine attack occurrence. 3. The highest excitability and facilitation of the trigeminocervical complex (increased amplitude and decreased latency of component R2) were observed during ictal phase that is additional evidence of the key role of the brainstem in migraine pathophysiology.


2013 ◽  
Vol 643 ◽  
pp. 104-107
Author(s):  
Yi Jie Gu ◽  
Qing Gang Zhang ◽  
Yun Bo Chen ◽  
Hong Quan Liu ◽  
Yan Min Wang ◽  
...  

The thermodynamic analysis of Ni2+-Mn2+-NH3-OH--H2O in co-precipitation system was carried out, and the precursor Ni1/2Mn1/2(OH)2 was prepared by hydroxide co-precipitation method. The analysis showed that the best pH value of mixed solution is 11 and the ammonia concentration is 0.4 mol/L, when NaOH is precipitating agent and ammonia is chelating agent. When the pH value is 11, the SEM images confirm that the morphology of Ni1/2Mn1/2(OH)2 is the best.


2020 ◽  
Vol 16 ◽  
Author(s):  
Imran Aslam ◽  
M. Saqib ◽  
M. W. Iqbal ◽  
Rajender Boddula ◽  
Tariq Mahmood ◽  
...  

Background: Environmental pollution has become a worldwide problem. In this regard, decontamination of wastewater and removal of organic pollutants from environment by photocatalysis has emerged as one of the most promising techniques from last few decades. Objective : In order to degrade the harmful pollutants from wastewater, highly efficient non-toxic Fe2(WO4)3 photocatalyst will be synthesized via co precipitation method. The photocatalytic activity of the as-synthesized material will be examined by degrading methylene blue (MB) under various conditions. Methods: For this purpose, different experimental parameters such as catalyst load, model compound concentration, H2O2 percentage and pH value were adjusted for excellent degradation of MB, and response surface methodology (RSM) along with central composite design (CCD) as adequate model was employed for optimization process. Results: The experimental results revealed that 1.2 g/L of catalyst load, 10 g/L for dye concentration, 0.5 percentage of H2O2 and pH 7 are found to be the optimized values for the aforesaid parameters. The optimized values led to 93% degradation of MB under UV light exposure. In addition, toxicological studies have been analysed by using various bioassays for both untreated and treated samples and a conspicuous reduction (69.12%) in the toxicity level was observed. Conclusion: The study signifies that this method is useful for reclamation of water making it useful for industry and irrigation.


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