A multilayer stack is described. The multilayer stack includes: (i) one or more inorganic barrier layers for reducing transport of gas or vapor molecules therethrough; (ii) an inorganic reactive layer disposed adjacent to one or more of the inorganic barrier layers, and the reactive layer capable of reacting with the gas or the vapor molecules; and (iii) wherein, in an operational state of the multilayer stack, the vapor or the gas molecules that diffuse through one or more of the inorganic barrier layers react with the inorganic reactive layer, and thereby allow said multilayer stack to be substantially impervious to the gas or the vapor molecules.

An electrochemical cell includes a housing having an inlet, an outlet, and a central axis and an anode-cathode pair disposed concentrically within the housing about the central axis and defining an active area between an anode and a cathode of the anode-cathode pair. An active surface area of at least one of the anode and the cathode has a surface area greater than a surface area of an internal surface of the housing. The anode-cathode pair is configured and arranged to direct all fluid passing through the electrochemical cell axially through the active area.

A process for treating a dicarboxylic acid composition, with the proviso that the dicarboxylic acid is not furan 2,5-dicarboxylic acid, which process comprises: introducing a dicarboxylic acid composition, which dicarboxylic acid composition contains an impurity compound and which impurity compound is an organic compound comprising a carbonyl group, into a cathode compartment of an electrochemical cell; and electrochemically reducing the impurity compound in the cathode compartment.

Systems and methods for electrochemical ammonia synthesis comprise electrolytes which have greater efficiency than water, thus leading to cost reductions; and/or cathode catalysts which have lower costs and higher efficiencies in comparison to the iron/nickel catalysts noted above. The electrolyte may be composed primarily of a combination of non-aqueous hydrogen bond donors and acceptors, with high nitrogen solubility and high conductivity. The cathode catalyst may be composed of either a manganese-doped oxide or carbonate material or a two-dimensional carbide or nitride material.

A method and an electrochemical cell for hydrogen production by electrochemical decomposition of a sulfur-containing acid gas such as H.sub.2S or SO.sub.2 are disclosed. The method comprises electrolysis of the acid gas in solution in the presence of an absorbent, which may be chemical, physical, or a mixture thereof. In typical embodiments, the absorbent is alkanolamine-based.

Systems and methods for generating reactive oxygen species formulations useful in various oxidation applications. Exemplary formulations include singlet oxygen or superoxide and can also contain hydroxyl radicals or hydroperoxy radicals, among others. Formulations can contain other reactive species, including other radicals. Exemplary formulations containing peracids are activated to generate singlet oxygen. Exemplary formulations include those containing a mixture of superoxide and hydrogen peroxide. Exemplary formulations include those in which one or more components of the formulation are generated electrochemically. Formulations of the invention containing reactive oxygen species can be further activated to generate reactive oxygen species using activation chosen from a Fenton or Fenton-like catalyst, ultrasound, ultraviolet radiation or thermal activation. Exemplary applications of the formulations of the invention among others include: cleaning in place applications, water treatment, soil decontamination and flushing of well casings and water distribution pipes.

A neutralization cell is provided which may be used to increase a pH level of a chlorine solution. The neutralization cell includes a neutralization anode, a neutralization cathode, an inlet, and an outlet. The neutralization anode and the neutralization cathode are positioned to divide the neutralization cell into a middle area between the neutralization anode and the neutralization cathode, an anode area on a side of the neutralization anode furthest from the neutralization cathode, and a cathode area on a side of the neutralization cathode furthest from the neutralization anode. The inlet directs the chlorine solution into the neutralization cell by directing an incoming flow of the chlorine solution into the anode area. The outlet directs the chlorine solution out of the neutralization cell by directing an outgoing flow of the chlorine solution from the cathode area.

An electrochemical reaction single cell including an electrolyte layer containing Zr and at least one of Y, Sc, and Ca, an anode disposed on one side of the electrolyte layer, a cathode containing Sr and Co and disposed on the other side of the electrolyte layer, and an intermediate layer disposed between the electrolyte layer and the cathode. In the electrochemical reaction single cell, an SrZrO.sub.3 integrated value calculated by a predetermined method is 600 to 10,300. Also disclosed is an electrochemical reaction cell stack including a plurality of electrochemical reaction single cells.

According to one embodiment, a photochemical reaction device includes: a solar cell; an electrolytic tank having a first tank storing a first solution including an oxidant and/or reductant of a redox medium and a second tank storing a second solution including water and/or proton; a first electrode set in the first tank, connected to a positive electrode of the solar cell through a first switching element, and connected to a negative electrode of the solar cell through a second switching element; and a second electrode set in the second tank, connected to the positive electrode of the solar cell through a third switching element, and connected to the negative electrode of the solar cell through a fourth switching element.

An electrolytic device of an embodiment has a solution or gas containing water and carbon dioxide, a first electrode oxidizing the water to produce oxygen, a second electrode and a third electrode reducing the carbon dioxide to produce a carbon compound, and a power supply applying current across the first electrode and the second and third electrodes. A composing material of the second electrode has an ionization tendency larger than a composing material of the third electrode. The third electrode mainly reduces the carbon dioxide to produce a first carbon compound, and the second electrode mainly reduces the first carbon compound to produce a second carbon compound.