Long-term stability of sulfated hydrous titania-based electrolyte for water electrolysis

Journal of Solid State Electrochemistry - The long-term stability in water was investigated for an inorganic proton conductor based on sulfated hydrous titania electrolyte in water electrolysis....     

Proton conduction properties of nano-titania modified by sulfuric acid impregnation

The proton conduction properties of sulfuric acid-modified nano-titania prepared by impregnation method were investigated. The proton conductivity of sulfuric acid-modified nano-titania was almost the same as that of hydrous sulfated nano-titania investigated in our previous work when the amount of adsorbed sulfate groups was almost the same. The highest conductivity was obtained at an adsorbed sulfate group amount of 0.42?mmol/g, not 0.97?mmol/g. This result indicates that the enhancement of conductivity with increasing amount of adsorbed sulfate groups is limited. This might be attributable to insufficient water molecule adsorption on the Ti⁴⁺ site coordinated with a bidentate sulfate group due to the prevention by excess sulfuric acid.     

Mixed conductivity, nonstoichiometric oxygen, and oxygen permeation properties in Co-Doped Sr3Ti2O(7-δ)

Electrical conductivity and oxygen permeation rates in Co-doped Sr(3)Ti(2)O(7-δ) with Ruddesden-Popper type structures were investigated. The effects of metal dopants (M) in the Ti site of Sr(3)Ti(2)(M)O(7-δ) on the mixed conductivity were also studied. Doping of Sr(3)Ti(2)O(7-δ) with Co was found to be effective for improving the electrical conductivity as well as the oxygen permeation rate, which could be assigned to the increased oxygen vacancy concentration by doping Co(3+) into Ti(4+) sites. The nonstoichiometric oxygen of these oxides was measured by using a thermal gravimetric method. The creation of oxygen vacancies, which is compensated with Co(3+) doping, leads to higher oxide ion conductivity. The oxygen permeation rate monotonously increased with increasing amounts of Co in the Ti site. Sr(3)Ti(0.8)Co(1.2)O(7-δ) exhibited high oxide ion conductivity and a large oxygen permeation rate. The highest oxygen permeation rate achieved a value of 2.02 cc min(-1) cm(-2) at 1273 K for Sr(3)Ti(0.8)Co(1.2)O(7-δ). Neutron diffraction analysis and redox titration suggests that the oxygen diffusion occurs through oxygen vacancies in the perovskite block, but not through excess oxygen in the rock salt block.     

<Emphasis Type="Italic">N</Emphasis>-soliton train and generalized complex Toda chain for the Manakov system

We analyze the dynamical behavior of the N-soliton train of the Manakov system and of the vector NLS equation in the adiabatic approximation. We prove that the dynamics of the N-soliton train in both cases are described by a generalized version of the complex Toda chain model. This fact can be used to predict the asymptotic regimes of the N-soliton train provided the initial soliton parameters are given. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 151, No. 3, pp. 391–404, June, 2007.