(JP11000552-A)      The gas reactor (10) comprises a dielectric casing (13) with a line (20) introducing gas (A). An electrode (11) in the casing extends axially along its centre. This is covered by a layer of catalyst (14). The second electrode (12) surrounds the casing. A unit (30) supplies alternating current to the electrodes, producing an internal discharge.    Preferably, the second electrode defines a localised discharge region, which surrounds the excitation catalyst (14) layer on the first electrode surface. An activation catalyst (16) is preferably formed on the first electrode, outside the discharge region. The layers preferably activate and excite the gas. A second line (21) preferably introduces a second gas (B). Its end is preferably connected to the dielectric line, mixing this gas with the first, which has passed through.    USE -   Used as a reactor synthesising gas by a synergistic combination of catalysis and gas discharge.    ADVANTAGE -   Although e.g. pollutant decomposition is feasible, exploiting the known synergism between catalysis and corona discharge, the above reactor uses synthesis by these means. The dielectric is used to produce a controlled, uniform glow discharge. A variety of catalysts may be included to activate and excite the first gas for desired reaction with the second. Reactions exemplified include the water gas shift reaction and the reaction between carbon monoxide and hydrogen, synthesising methane and carbon dioxide.    (US6027617-A)      The gas reactor (10) comprises a dielectric casing (13) with a line (20) introducing gas (A). An electrode (11) in the casing extends axially along its centre. This is covered by a layer of catalyst (14). The second electrode (12) surrounds the casing. A unit (30) supplies alternating current to the electrodes, producing an internal discharge.    Preferably, the second electrode defines a localised discharge region, which surrounds the excitation catalyst (14) layer on the first electrode surface. An activation catalyst (16) is preferably formed on the first electrode, outside the discharge region. The layers preferably activate and excite the gas. A second line (21) preferably introduces a second gas (B). Its end is preferably connected to the dielectric line, mixing this gas with the first, which has passed through.    USE -   Used as a reactor synthesising gas by a synergistic combination of catalysis and gas discharge.    ADVANTAGE -   Although e.g. pollutant decomposition is feasible, exploiting the known synergism between catalysis and corona discharge, the above reactor uses synthesis by these means. The dielectric is used to produce a controlled, uniform glow discharge. A variety of catalysts may be included to activate and excite the first gas for desired reaction with the second. Reactions exemplified include the water gas shift reaction and the reaction between carbon monoxide and hydrogen, synthesising methane and carbon dioxide.