The invention discloses a metal and semi-metal oxide powder that, when applied to an environment, inhibits the growth of colonies of microorganisms, wherein the powder includes particles comprising a particle size distribution between 0.1 to 100 microns, which are formulated as a strongly bonded, porous, composite of nano-scale grains of materials wherein the grains have a surface area of 75 to 300 m.sup.2/g and which have less than about 10.sup.−4% of free radical species by weight, and wherein the powder is adapted to release reactive oxygen species (ROS) burst when the particles come into contact with a microorganism.

Disclosed is a technique for capturing, refining and storing byproduct hydrogen generated by a seawater electrolyzer, using the byproduct hydrogen in an energy system, and producing high-purity magnesium oxide from alkali byproducts additionally produced after seawater electrolysis. An energy system 100 may include a seawater electrolyzer 110 generating a chlorine substance by electrolyzing seawater, a hydrogen storage unit 120 capturing, refining, and storing byproduct hydrogen generated in the electrolysis process by the seawater electrolyzer, a fuel cell 130 using, as fuel, the byproduct hydrogen stored in the hydrogen storage unit, an MgO acquisition unit 140 converting, into magnesium oxide, magnesium hydroxide additionally generated from the seawater in the seawater electrolyzer, a hydrogen capture pipe 150 having one side coupled to the seawater electrolyzer and other side coupled to the hydrogen storage unit and transferring the byproduct hydrogen from the seawater electrolyzer to the hydrogen storage unit.

Disclosed is a technique for capturing, refining and storing byproduct hydrogen generated by a seawater electrolyzer, using the byproduct hydrogen in an energy system, and producing high-purity magnesium oxide from alkali byproducts additionally produced after seawater electrolysis. An energy system 100 may include a seawater electrolyzer 110 generating a chlorine substance by electrolyzing seawater, a hydrogen storage unit 120 capturing, refining, and storing byproduct hydrogen generated in the electrolysis process by the seawater electrolyzer, a fuel cell 130 using, as fuel, the byproduct hydrogen stored in the hydrogen storage unit, an MgO acquisition unit 140 converting, into magnesium oxide, magnesium hydroxide additionally generated from the seawater in the seawater electrolyzer, a hydrogen capture pipe 150 having one side coupled to the seawater electrolyzer and other side coupled to the hydrogen storage unit and transferring the byproduct hydrogen from the seawater electrolyzer to the hydrogen storage unit.

Carbon dioxide can be converted into a higher energy product by contacting carbon dioxide with a polarized monocrystalline magnesium oxide producing at least in part carbon. Further a novel crystalline magnesium oxide carbon composite comprising crystalline magnesium oxide and crystalline carbon having graphene structure which are interwoven is provided.

Carbon dioxide can be converted into a higher energy product by contacting carbon dioxide with a polarized monocrystalline magnesium oxide producing at least in part carbon. Further a novel crystalline magnesium oxide carbon composite comprising crystalline magnesium oxide and crystalline carbon having graphene structure which are interwoven is provided.

A method for increasing the conductivity of a metal oxide with crystal structure belonging to the 4/m 32/m point group is provided. Single crystal oxides with crystal structure belonging to 4/m 32/m point group are contacted with nitrogen gas, with oxygen gas, with nitrogen gas, with oxygen gas, then with nitrogen gas to increase the conductivity of the metal oxide with crystal structure belonging to the 4/m 32/m point group.

A method for increasing the conductivity of a metal oxide with crystal structure belonging to the 4/m 32/m point group is provided. Single crystal oxides with crystal structure belonging to 4/m 32/m point group are contacted with nitrogen gas, with oxygen gas, with nitrogen gas, with oxygen gas, then with nitrogen gas to increase the conductivity of the metal oxide with crystal structure belonging to the 4/m 32/m point group.

Herein discloses a method of carbonating reactive magnesia cement, which includes: (i) providing an aqueous suspension including a carbon dioxide-producing bacteria; (ii) mixing the aqueous suspension with a precursor which the carbon dioxide-producing bacteria generates carbon dioxide from for a duration to form an aqueous mixture sufficient for substantially carbonating the reactive magnesia cement; (iii) mixing the aqueous mixture with the reactive magnesia cement to form a blend; wherein a nutrient is provided in the aqueous suspension of step (i) or in the reactive magnesia cement of step (iii) to sustain the carbon dioxide-producing bacteria in the reactive magnesia cement; and (iv) curing the blend to carbonate the reactive magnesia cement. A reactive magnesia cement composite formed by the method is also disclosed.

Herein discloses a method of carbonating reactive magnesia cement, which includes: (i) providing an aqueous suspension including a carbon dioxide-producing bacteria; (ii) mixing the aqueous suspension with a precursor which the carbon dioxide-producing bacteria generates carbon dioxide from for a duration to form an aqueous mixture sufficient for substantially carbonating the reactive magnesia cement; (iii) mixing the aqueous mixture with the reactive magnesia cement to form a blend; wherein a nutrient is provided in the aqueous suspension of step (i) or in the reactive magnesia cement of step (iii) to sustain the carbon dioxide-producing bacteria in the reactive magnesia cement; and (iv) curing the blend to carbonate the reactive magnesia cement. A reactive magnesia cement composite formed by the method is also disclosed.

Provided is a method of preparing a metal oxide-silica composite aerogel and a metal oxide-silica composite aerogel having an excellent weight reduction property prepared by the method. The method comprises adding an acid catalyst to a first water glass solution to prepare an acidic water glass solution (step 1); adding a metal ion solution to the acidic water glass solution to prepare a precursor solution (step 2); and adding a second water glass solution to the precursor solution and performing a gelation reaction (step 3).