Impregnation of Acetylene Black Electrodes with a Polytetrafluoroethylene Binder with an Aqueous Solution and Evaluation of Its Specific Double Layer Capacity

The effect of (0.05 M) tetraalkylammonium salt additions in aqueous 0.5 M KOH on the rate of impregnation of carbon black electrodes with a polytetrafluoroethylene binder (5–20 wt % PTFE) at hydrogen evolution potentials was studied. It was shown that tetraalkylammonium salts facilitate the fast filling of electrodes with electrolyte, and their effect increases with the molecular mass of the cation. Tetramethylammonium bromide showed the weakest effect. In solutions with tetrabutylammonium bromide, the electrodes were completely flooded with 5 wt % PTFE within 15 min. Diethyldibenzylammonium bromide had a similar effect. The influence of the PTFE concentration in the electrodes on their capacity was studied. The specific capacity of acetylene black in acid and alkaline aqueous solutions was evaluated from the electrode surface area determined by low-temperature nitrogen adsorption (BET).     

Effect of trialkylammonium salts and current density on the electrosynthesis of hydrogen peroxide from oxygen in a gas-diffusion electrode in acid solutions

The influence exerted by the nature of cation of a supporting electrolyte and by the current density on the electroreduction of oxygen to hydrogen peroxide in acid K₂SO₄ solutions (pH 0.9–1.4) in gas-diffusion hydrophobized carbon black electrodes with varied electrolyte porosity was studied.     

Application of Multinuclear MAS NMR for the in situ Monitoring of Hydrothermal Synthesis of Zeolites

In situ MAS NMR studies on the monitoring of hydrothermal synthesis of zeolites are reviewed. The first part of the review contains information on the experimental techniques used for the in situ NMR studies in static and MAS conditions. In the second part, the main capabilities of the in situ ¹H, ¹¹B, ¹³C, ¹⁴N, ¹⁹F, ²³Na, ²⁷Al, ²⁹Si and ³¹P MAS NMR for the elucidation of the mechanism of hydrothermal synthesis of zeolites are examined and the data on NMR lines identification are summarized. In the last part the main application areas of the techniques are considered and illustrated with examples taken from the mechanistic studies of zeolites A, X, MFI and BEA synthesis. A cross-reference index between the materials studied, the experimental approaches used, the mechanistic information obtained, and the corresponding literature sources is established.     

Role of the Aluminophosphate Gel Aging Stage in Controlling the Morphology and Secondary Pore Structure of AlPO4-11 Molecular Sieves

Kinetics and Catalysis - The effect of the aging stage on the chemical and phase composition and pore structure characteristics of aluminophosphate gels synthesized using boehmite and phosphoric...     

The Prospects of the in situ and ex situ Use of Aqueous Solutions of Hydrogen Peroxide Electrogenerated from Oxygen

Russian Journal of Electrochemistry - The results and prospects of the in situ (in the cell volume) and ex situ (outside the cell) use of aqueous solutions of hydrogen peroxide electrogenerated...     

Comparative Study of the Efficiency of New Technical Carbons СН210 and С40 in Electrosynthesis of Н2О2 from О2 in Gas-Diffusion Electrodes on Their Basis

Russian Journal of Electrochemistry - The efficiency of new brands of technical carbon CH210 and C40 in the electrogeneration of Н2О2 from О2 in gas-diffusion electrodes (GDE) on...     

Studies of silicon nanocluster ligand coating by solid-state NMR

Silicon nanoclusters were studied by ²⁹Si and ¹³C MAS NMR (magic angle spinning) spectroscopy. We for the first time confirmed the cleavage of ordinary ether C—O bonds of the solvent in the process of the synthesis of nanoclusters and the “binding” of the decomposition products to the surface of silicon nanoparticles as ligands. The applicability of MAS NMR spectroscopy in the studies of silicon nanocluster ligand coating and in the determination of the processes leading to the formation of the nanoparticle ligand shell was demonstrated.     

Estimate of polarization components in oxygen reduction process on expanded natural graphites and acetylene carbon black in acid and alkaline electrolytes

The polarization curves of oxygen reduction in gas diffusion electrodes of expanded natural graphites (ENG, prepared from graphite intercalation compounds synthesized by intercalation of sulfuric and nitric acids into natural graphites GAK-3 and GT-1) and acetylene carbon black in acid (pH 0.6) and alkaline (3 M KOH) electrolytes were analyzed. The transfer coefficients and oxygen reduction exchange currents on ENG and acetylene carbon black were estimated. The experimental polarization curves were described well with the derived semi-empirical equations.