The present invention discloses a novel capacitive vapor sensor comprising porous immobilized graphene oxide (pGO) on an electrode surface. Also disclosed is an in-situ process for the preparation of this sensor and various uses thereof.

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 PtRh 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 PtRh 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 %.

An electrochemical sensor is provided which may be formed using micromachining techniques commonly used in the manufacture of integrated circuits. This is achieved by forming microcapillaries in a silicon substrate and forming an opening in an insulating layer to allow environmental gases to reach through to the top side of the substrate. A porous electrode is printed on the top side of the insulating layer such that the electrode is formed in the opening in the insulating layer. The sensor also comprises at least one additional electrode. The electrolyte is then formed on top of the electrodes. A cap is formed over the electrodes and electrolyte. This arrangement may easily be produced using micromachining techniques.

To be provided is a metal paste from which an electrode having high electrode activity as a sensor electrode of various gas sensors can be produced. The present invention is a metal paste for forming a gas sensor electrode obtained by dispersing a conductive particle including Pt or a Pt alloy and a ceramic powder including zirconia or stabilized zirconia, or any of zirconia and stabilized zirconia and one or more oxides of La, Ce, Pr, Nd, Sm, and Hf in a solvent, the metal paste further including an inorganic oxide particle containing alumina and an insoluble particle that is insoluble in the solvent, in which 0.5 or more to 3.0 mass % or less of the inorganic oxide particle and 1.0 to 5.0 mass % of the insoluble particle are dispersed based on the mass of the solid content of the conductive particle, the ceramic powder, the inorganic oxide particle, and the insoluble particle.

An electrode for an electrochemical cell is disclosed which has a first layer containing a first electrode material of formula Pr.sub.(1-x)Ln.sub.xO.sub.(2-0.5x-). Ln is selected from at least one rare earth metal, 8 is the degree of oxygen deficiency, and 0.01x0.4. The rare earth metal may be a lanthanide, scandium or yttrium. Also disclosed is an electrochemical cell having such an electrode and methods of making such an electrochemical cell. The electrochemical cell may be an electrolytic cell, an oxygen separator, a sensor or a fuel cell. Also disclosed are materials of formula Pr.sub.(1-x)Ln.sub.xO.sub.(2-0.5x-) and Pr.sub.(1-x)Sm.sub.xO.sub.(2-0.5x-).

Disclosed are a hydrogen detection sensor and a method of manufacturing the same. The hydrogen detection sensor is manufactured by using hydrothermal synthesis method to synthesize a molybdenum oxide (MoO.sub.3) nanostructure, and irradiating UV light thereon to form an MoO.sub.3Pd nanocomposite comprising the molybdenum oxide nanostructure with palladium (Pd) catalyst particles, and coating the MoO.sub.3Pd nanocomposite on a substrate. As such, a visible color change from the MoO.sub.3 before and after exposure to hydrogen may be so obvious that the sensing or sensitivity of hydrogen and the long-term stability may be substantially improved. In addition, the manufacturing process is simple, and the manufacturing costs may be reduced.

The limiting-current type gas sensor includes: a porous lower electrode disposed on a substrate; an insulating film disposed on the porous lower electrode; a solid electrolyte layer disposed on the porous lower electrode in an opening formed by patterning the insulating film, and further disposed on the insulating film surrounding the opening; and a porous upper electrode disposed on the solid electrolyte layer, wherein the insulating film realizes non-contact between an edge face of the solid electrolyte layer and the porous lower electrode, in order to suppress the intake of oxygen (O) ion from the edge face of the solid electrolyte layer, and thereby the surface-conduction current component between the porous upper electrode and the porous lower electrode can be reduced. There can be provided the limiting-current type gas sensor capable of reducing the surface-conduction current component and realizing low power consumption.

A system for detecting an analyte gas including a system housing having an inlet system, an electrochemical gas sensor within the housing and in fluid connection with the inlet system, the electrochemical sensor including a working electrode responsive to the analyte gas, and a control system in electrical connection with the working electrode. The control system is operative to bias the working electrode at a first potential at which the electrochemical gas sensor is responsive to the analyte gas and operative to bias the working electrode at a second potential, different from the first potential, at which the electrochemical gas sensor is sensitive to a driving force created in the vicinity of the inlet system to test at least one transport path of the system.

An electrode (100) for an electrochemical gas sensor (1), wherein the electrode has a gas-permeable membrane (4). A graphene layer (3) is applied as an electrode material to the gas-permeable membrane (4). Such an electrode (1) is prepared, for example, by applying a dispersion of graphene or graphene oxide in a volatile liquid to the gas-permeable membrane and evaporating the volatile liquid.

Embodiments of the invention are directed to a system for detecting neurotransmitters. A non-limiting example of the system includes a porous electrode. A system can also include a pH sensor attached to the porous electrode, wherein the pH sensor includes a sensing electrode and a reference electrode. The system can also include electronic circuitry in communication with the pH sensor.