A method of manufacturing a gas sensor for detecting xylene is provided. A method of manufacturing a gas sensor includes reacting a mixed material including a first material containing a cobalt (Co) element and a second material containing a chromium (Cr) element to form a CoCr.sub.2O.sub.4 hollow structure having a hollow shape.

A method for preparing copper-nickel cobaltate nanowires includes steps of: (1) dissolving a soluble nickel salt, cobalt salt and copper salt in ultrapure water, and preparing same into a mixed salt solution A; (2) adding 1-4 mmol of sodium dodecyl sulfate to solution A, and dissolving same with stirring; (3) dissolving 12-30 mmol of hexamethylenetetramine in 20 mL of ultrapure water to form solution B; (4) slowly dropwise adding solution B to solution A via a separatory funnel to form solution C, and stirring same for 0.5-1 h; and (5) further transferring same into a 100 mL reaction vessel, reacting same at 100-160 C. for 8-20 h, suction filtration and washing, and drying same at 40-60 C. in a vacuum oven, and further reacting same at 350-800 C. for 1-4 h in a muffle furnace.

An objective of the present invention is to provide a positive electrode active material that can inhibit the capacity changes associated with temperature variations, and an alkaline battery that contains this positive electrode active material. Aluminum and ytterbium are at least partially solid-dissolved in nickel hydroxide in the nickel composite hydroxide present in the positive electrode active material of the present invention.

Sintering is an important issue in creating crystalline metal oxides with high porosity and surface area, especially in the case of high-temperature materials such as metal aluminates. Herein we report a rationally designed synthesis of metal aluminates that diminishes the surface area loss due to sintering. Metal aluminate (e.g. MeAl.sub.2O.sub.4or MeAlO.sub.3Me=Mg, Mn, Fe, Ni, Co, Cu, La, or Ce; or mixture thereof) supported on -Al.sub.2O.sub.3 with ultralarge mesopores (up to 30 nm) was synthesized through microwave-assisted peptization of boehmite nanoparticles and their self-assembly in the presence of a triblock copolymer (Pluronic P123) and metal nitrates, followed by co-condensation and thermal treatment. The resulting materials showed the surface area up to about 410 m.sup.2.Math.g.sup.1, porosity up to about 2.5 cm.sup.3.Math.g.sup.1, and very good thermal stability. The observed enhancement in their thermomechanical resistance is associated with the faster formation of the metal aluminate phases. The nanometer scale path diffusion and highly defective interface of -alumina facilitate the counter diffusion of Me.sup.X+ and Al.sup.3+ species and further formation of the metal aluminate phase.

A process for oxidizing water using hydrated cobalt molybdenum is disclosed. A plurality of hydrated cobalt molybdenum nanoparticles are supported on an electrode and are able to catalytically interact with water molecules generating oxygen. The catalyst can be used as part of an electrochemical or photo-electrochemical cell for the generation of electrical energy.

A spinel compound oxide particle includes metallic atoms, aluminum atoms, oxygen atoms, and molybdenum atoms, wherein the metallic atoms are selected from the group consisting of zinc atoms, cobalt atoms, and strontium atoms, and a crystallite size in a [111] plane is 100 nm or more. Included are a step (1) of firing a first mixture including a molybdenum compound and a metallic-atom-containing compound or a first mixture including a molybdenum compound, a metallic-atom-containing compound, and an aluminum compound to prepare an intermediate; and a step (2) of firing, at a temperature higher than a temperature selected in the step (1), a second mixture including the intermediate or a second mixture including the intermediate and an aluminum compound.

Manganese-cobalt (MnCo) spinel oxide nanowire arrays are synthesized at low pressure and low temperature by a hydrothermal method. The method can include contacting a substrate with a solvent, such as water, that includes MnO4- and Co2 ions at a temperature from about 60 C. to about 120 C. The method preferably includes dissolving potassium permanganate (KMnO4) in the solvent to yield the MnO4 ions. the substrate is The nanoarrays are useful for reducing a concentration of an impurity, such as a hydrocarbon, in a gas, such as an emission source. The resulting material with high surface area and high materials utilization efficiency can be directly used for environment and energy applications including emission control systems, air/water purifying systems and lithium-ion batteries.

The invention relates to a method for producing a metal chalcogenide thin film electrode, comprising the steps: (a) contacting a metal or metal oxide with an elementary halogen in a non-aqueous solvent, producing a metal halide compound in the solution, (b) applying a negative electric voltage to an electrically conducting or semiconducting substrate which is in contact with the solution from step (a), and (c) during and/or after step (b) contacting the substrate with an elementary chalcogen forming a metal chalcogenide layer on the substrate. The invention also relates to a metal chalcogenide thin film electrode which can be produced by the method and its use as an anode for releasing oxygen during (photo)electrochemical water splitting.

An anode material for a secondary battery is provided. The anode material for the secondary battery includes a metal oxide containing four or more than four elements, or an oxide mixture containing four or more than four elements. The metal oxide includes cobalt-copper-tin oxide, silicon-tin-iron oxide, copper-manganese-silicon oxide, tin-manganese-nickel oxide, manganese-copper-nickel oxide, or nickel-copper-tin oxide. The oxide mixture includes the oxide mixture containing cobalt, copper and tin, the oxide mixture containing silicon, tin and iron, the oxide mixture containing copper, manganese and silicon, the oxide mixture containing tin, manganese and nickel, the oxide mixture containing manganese, copper and nickel, or the oxide mixture containing nickel, copper and tin.

An anode material for a secondary battery is provided. The anode material for the secondary battery includes a metal oxide containing four or more than four elements, or an oxide mixture containing four or more than four elements. The metal oxide includes cobalt-copper-tin oxide, silicon-tin-iron oxide, copper-manganese-silicon oxide, tin-manganese-nickel oxide, manganese-copper-nickel oxide, or nickel-copper-tin oxide. The oxide mixture includes the oxide mixture containing cobalt, copper and tin, the oxide mixture containing silicon, tin and iron, the oxide mixture containing copper, manganese and silicon, the oxide mixture containing tin, manganese and nickel, the oxide mixture containing manganese, copper and nickel, or the oxide mixture containing nickel, copper and tin.