Papers by Keyword: Hydrogen Peroxide

Abstract: Cadmium ion doping was carried out during electrochemically cathodic plating nickel hydroxide on platinum films coated n-silicon (Pt/n-n⁺-Si electrode) in 0.1 M nickel nitrate solution containing 0.035 M cadmium nitrate. The morphology and composition of the products were characterized by scanning electron microscope (SEM) and x-ray photoelectron spectroscopy (XPS), respectively. A two-electrode cell based on Cd-doped NiO/Pt/n-n⁺-Si electrode and a platinum counter has been used for determination of hydrogen peroxide in absence of reference electrode by photocurrent measurement at a zero bias. The emphasis is laid on that the cadmium doping remarkably improves the sensibility of the photoelectrochemical hydrogen peroxide sensor. Under optimizing conditions a sensitivity of 254.6 μA mM^-1 cm^-2 and a linear response range from 0.02 mM up to 0.12 mM with a determination limit of 2.0 μM were achieved in a potassium hydroxide (KOH) solution at pH =13.3.

Abstract: . New developments in green catalytic oxidations of alcohols with H₂O₂ as oxidant in last decade are reviewed. Emphasis is placed on introducing the heterogeneous catalysts supported on different material in various of reactions, mechanism features are discussed as well.

Abstract: Degradation of paraoxon and thioanisole (PhSMe) were studied using NH₃ modified H₂O₂ solution as decontaminant. Degradation rates of paraoxon depend exponentially on pH of the modified solution. Nucleophilic substitution mediated by HOO^- is the major degradation mechanism and at least two orders of magnitude faster than hydrolysis. Proton catalytic oxidation and solvent-aided oxidation contribute differently to the primary oxidation of PhSMe (PhSMe→PhS(O)Me), and the apparent kinetic constants (k_ap) of the primary oxidation show a three-stage profile with pH of the NH₃-modified H₂O₂ solution. Secondary oxidation of PhSMe (PhS(O) Me→PhS(O)₂Me) is much slower than the primary oxidation in the modified H₂O₂ solution, and the yield of PhS(O)₂Me depended exponentially on pH too. The best pH range for the NH₃ modified H₂O₂ solution as a broad-spectrum decontaminant is at 9.5-10.0 since a balance of nucleophilic/oxidizing decontamination reactivity could be achieved.

Abstract: Ultrapure water (UPW) is widely used for rinsing wafers and diluting chemicals in semiconductor manufacturing processes. The quality of UPW is severely controlled, but the generation of hydrogen peroxide (H₂O₂) as a impurity is inevitable due to the ultraviolet irradiation in a UPW production system (Figure 1). In our survey, it is revealed that the concentration of H₂O₂ in UPW reaches to 10~40 μg/L level. Considering the situation, we have developed a palladium-loaded monolithic anion exchange resin (Pd-M) as a catalyst that is able to remove H₂O₂ from UPW down to below 1 μg/L at an extremely high flow rate (space velocity SV = 6,000 h^-1), with no detectable elution of impurities [1, 2]. Furthermore, we have found that the dissolution rate of copper which is easy to be corroded oxidatively in CO₂-dissolved water (CO₂ UPW) [3] can be decreased to one-third by removal of H₂O₂ from CO₂ UPW using Pd-M catalyst [4]. In this study, we present the effects of H₂O₂ removal from UPW and diluted hydrofluoric acid (DHF) on the surfaces of copper, molybdenum and silicon.

Abstract: Incorporating substrates with higher charge mobilities than Si and Ge in metal-oxide-semiconductor field-effect transistors (MOSFETs) would extend the scaling of this device architecture. III-V semiconductors are candidates, and etching and passivation processes are needed that are selective and yield smooth surfaces. The (100) face of III-V compounds contains both electron-deficient group III (Ga, In) atoms and electron-rich group V (P, As, Sb) atoms. Etching InP(100) in a mixture of HCl and H₂O₂ chlorinates the In (group III) atom forming a soluble product [1,2], yet the P (group V) atom is more reactive and is depleted from the surface [3]. α-Hydroxy acids (lactic, citric, malic, and tartaric) have been shown to bind to the group III atom [3] and could promote more uniform etching. This paper compares the surface chemistry of GaAs and InAs after etching in HCl and H₂O₂ mixtures with and without tartaric acid.

Abstract: The possibility of aromatic petroleum resin liquidphase oxidation was investigated. The influence of various factors on the modification process and properties oxidized samples was studied. The optimal parameters of the oxidation processes with hydrogen peroxide using interphase catalysis mechanisms, with peracetic acid, and with the electrogenerated oxidants complex of peroxide nature.

Abstract: Ozonation of humic acid has been conducted in the presence of hydrogen peroxide as catalyst. Besides the study of total organic carbon removal in the ozonation, ozonation by-products were investigated through the change of injected concentration of H₂O₂, initial pH of aqueous humic acid and injection time of H₂O₂. The variation of hydrogen peroxide and formaldehyde contents in the processes are mainly evaluated. The formaldehyde was formed less in ozonation with hydrogen peroxide system than without it. When initial pH in solution was changed from 3.5 to 10.5, the formaldehyde was formed with the highest concentration at pH 5. In addition, the concentration of H₂O₂ produced by ozonation was found to be increased with decreasing pH of the sample solution in this process.

Abstract: In dairy farming simulated wastewater resorcinol as the research object, using hydrogen peroxide treatment method to study the effect of resorcinol, the results showed that: when the initial concentration of hydroquinone 1.0g / L, 1.5g / L, 2.0g / L, 2.5g / L, 3.0g / L, the degradation rate was: 45.95%, 44.72%, 40.86%, 35.37%, 31.23%. Resorcinol degradation rate increases with the decrease of the initial concentration, that is beneficial to the low initial concentration of degradation, but the higher the initial concentration of the degradation rate. When the amount of hydrogen peroxide is 1mL, 1.5mL, 2mL, 2.5mL, when 3mL, the degradation rate was: 60.40%, 63.54%, 68.13%, 75.87%, 80.94%. Studies have shown that ultrasound combined with hydrogen peroxide is a good resorcinol degradation of organic pollutants in new ways.

Abstract: A water-soluble fluorescent probe was described for detecting hydrogen peroxide with the carbazole-derived as fluorophore and boronate moiety as recognition unit. The probe was developed as a turn-off fluorescent chemosensor with fast, high selectivity and sensitivity toward H₂O₂ over other biological reactive oxygen species. What is more, the probe was quenched linear response to H₂O₂ concentration in the range of 1.0×10⁻⁸ - 2.0×10⁻⁵ M and lower detection limit down to 6 nM (S / N = 3) was obtained.

Abstract: In this paper the different proportional Pt/Ag on XC-72 carbon are studied to serve as the electro-catalysts of H₂O₂ in acid media. All catalysts are prepared by impregnation reduction method and characterized by XRD and TEM. The electrochemical performance tests are examined by cyclic voltammetry (CV) at 25°C and 30°C, respectively. The results suggest that the peak current density increases with increasing the Ag content in Pt-Ag/C. Attributed to the temperature factor, the electro-catalytic activity of all catalysts at 30°C is better than that of 25°C.