Abstract: A hydrogen generator includes a reaction vessel, a water supply, a temperature adjustor, and a controller. The reaction vessel houses a hydrogen generating material having hydrogen generating ability. The hydrogen generating material includes a two-dimensional hydrogen boride sheet having a two-dimensional network and containing multiple negatively charged boron atoms. The controller is configured to execute a hydrogen generating mode to generate hydrogen from the hydrogen generating material and a regenerating mode to recover the hydrogen generating ability of the hydrogen generating material. The controller controls the temperature adjustor to heat the hydrogen generating material at a first predetermined temperature during the hydrogen generating mode. The controller controls the temperature adjustor to adjust the temperature of the hydrogen generating material to a second predetermined temperature and controls the water supply to supply water during the regenerating mode.

Abstract: A deterioration determination apparatus is usable with an ammonia sensor that includes an ammonia element portion that includes, a solid electrolyte, an ammonia electrode, and a reference electrode. The deterioration determining apparatus compares a first evaluation value and a second evaluation value, and determines whether deterioration has occurred in the ammonia element portion of the ammonia sensor at an evaluation time or subsequent to the evaluation time. The first evaluation value is based on a first sensor current obtained when a DC voltage is applied between the ammonia electrode and the reference electrode of the ammonia element portion at an initial time that is during an initial use period of the ammonia sensor. The second evaluation value is based on a second sensor current obtained when the DC voltage is applied between the ammonia electrode and the reference electrode subsequent to the initial period of use of the ammonia sensor.

Abstract: A hydrogen generator includes a reaction vessel, a water supply, a temperature adjustor, and a controller. The reaction vessel houses a hydrogen generating material having hydrogen generating ability. The hydrogen generating material includes a two-dimensional hydrogen boride sheet having a two-dimensional network and containing multiple negatively charged boron atoms. The controller is configured to execute a hydrogen generating mode to generate hydrogen from the hydrogen generating material and a regenerating mode to recover the hydrogen generating ability of the hydrogen generating material. The controller controls the temperature adjustor to heat the hydrogen generating material at a first predetermined temperature during the hydrogen generating mode. The controller controls the temperature adjustor to adjust the temperature of the hydrogen generating material to a second predetermined temperature and controls the water supply to supply water during the regenerating mode.

Abstract: An ammonia detector includes a solid electrolyte body, a detection electrode, and a reference electrode. The solid electrolyte body includes a measured gas facing surface, which comes into contact with a measured gas, and a reference gas facing surface, which comes into contact with a reference gas. The detection electrode is formed on the measured gas facing surface of the solid electrolyte body. The reference electrode is formed on the reference gas facing surface of the solid electrolyte body. The detection electrode contains at least alumina and 50% or more by mass of Pd.

Abstract: A deterioration determination apparatus is usable with an ammonia sensor that includes an ammonia element portion that includes, a solid electrolyte, an ammonia electrode, and a reference electrode. The deterioration determining apparatus compares a first evaluation value and a second evaluation value, and determines whether deterioration has occurred in the ammonia element portion of the ammonia sensor at an evaluation time or subsequent to the evaluation time. The first evaluation value is based on a first sensor current obtained when a DC voltage is applied between the ammonia electrode and the reference electrode of the ammonia element portion at an initial time that is during an initial use period of the ammonia sensor. The second evaluation value is based on a second sensor current obtained when the DC voltage is applied between the ammonia electrode and the reference electrode subsequent to the initial period of use of the ammonia sensor.

Abstract: A gas sensor element of the present disclosure includes a measurement gas chamber, a solid electrolyte body, and a sensor electrode. The sensor electrode has a noble metal region which contains at least Rh and Pt, an electrolyte region which is formed by a solid electrolyte, and a mixed region in which the noble metal and the solid electrolyte are mixed. With respect to a correlation curve which represents a correlation between a mass percentage concentration c of Rh and a thickness d of the mixed region, when a reaction resistance to a measured gas in the sensor electrode is 40 k?, the concentration c of Rh and the thickness d are set so that at coordinates (c, d), the concentration c has a positive coordinate point and the thickness d has a positive coordinate point.

Abstract: Disclosed is an ammonia sensor element having a measured gas chamber, a reference gas chamber and a solid electrolyte body arranged therebetween. The solid electrolyte body has a first main surface facing the measured gas chamber and a second main surface facing the reference gas chamber. A detection electrode is formed on the first main surface. A reference electrode is formed on the second main surface. The solid electrolyte body contains a first proton conducting solid electrolyte. The detection electrode contains a second proton conducting solid electrolyte. The second proton conducting solid electrolyte has an acid strength greater than that of the first proton conducting solid electrolyte.

Abstract: A gas sensor includes a sensor element. The sensor element includes; a solid electrolyte body that has oxygen ion conductivity and includes a first main surface exposed to a gas to be measured and a second main surface exposed to a reference gas; a sensor electrode that is provided on the first main surface and detects a specific gas component in the gas to be measured; and a reference electrode that is provided on the second main surface. The sensor electrode is made of a Pt—Rh alloy that contains 30 mass % to 70 mass % Pt and 70 mass % to 30 mass % Rh, when an overall noble metal component is 100 mass %. A variation amount of the Rh content of the Pt—Rh alloy from an outermost surface to a depth of 350 nm in a thickness direction of the sensor electrode is within a range of up to 10 mass %.

Abstract: Disclosed is an ammonia sensor element having a measured gas chamber, a reference gas chamber and a solid electrolyte body arranged therebetween. The solid electrolyte body has a first main surface facing the measured gas chamber and a second main surface facing the reference gas chamber. A detection electrode is formed on the first main surface. A reference electrode is formed on the second main surface. The solid electrolyte body contains a first proton conducting solid electrolyte. The detection electrode contains a second proton conducting solid electrolyte. The second proton conducting solid electrolyte has an acid strength greater than that of the first proton conducting solid electrolyte.

Abstract: A gas sensor element of the present disclosure includes a measurement gas chamber, a solid electrolyte body, and a sensor electrode. The sensor electrode has a noble metal region which contains at least Rh and Pt, an electrolyte region which is formed by a solid electrolyte, and a mixed region in which the noble metal and the solid electrolyte are mixed. With respect to a correlation curve which represents a correlation between a mass percentage concentration c of Rh and a thickness d of the mixed region, when a reaction resistance to a measured gas in the sensor electrode is 40 k?, the concentration c of Rh and the thickness d are set so that at coordinates (c, d), the concentration c has a positive coordinate point and the thickness d has a positive coordinate point.

Abstract: A gas sensor includes a sensor element. The sensor element includes; a solid electrolyte body that has oxygen ion conductivity and includes a first main surface exposed to a gas to be measured and a second main surface exposed to a reference gas; a sensor electrode that is provided on the first main surface and detects a specific gas component in the gas to be measured; and a reference electrode that is provided on the second main surface. The sensor electrode is made of a Pt—Rh alloy that contains 30 mass % to 70 mass % Pt and 70 mass % to 30 mass % Rh, when an overall noble metal component is 100 mass %. A variation amount of the Rh content of the Pt—Rh alloy from an outermost surface to a depth of 350 nm in a thickness direction of the sensor electrode is within a range of up to 10 mass %.