TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The catalyst comprises nickel or nickel alloy prepared by coprecipitation with high activity and stability. The catalyst comprises a metal selected from nickel oxide (100 wt.%); nickel oxide (81 wt.%) and alumina (19 wt.%); nickel oxide (93 wt.%) and alumina (7 wt.%); nickel oxide (77 wt.%), copper oxide (16 wt.%) and alumina (7 wt.%); nickel oxide (54 wt.%), copper oxide (27 wt.%) and alumina (9 wt.%); and nickel oxide (83 wt.%), magnesium oxide (6 wt.%) and alumina (11 wt.%).    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred System: The system (S1) further comprises a hydrogen source in flow communication with the reactor configured to provide a flow of hydrogen gas for pretreating the catalyst; an inert gas source in flow communication with the reactor configured to provide a flow of inert gas for purging the reaction chamber; an infrared sensor configured to measure a temperature of the methane plasma; and a gas chromatograph configured to analyze a chemical composition of the product gas. In the system (S1), the reactor includes a microwave transparent holder configured to hold the catalyst in contact with the methane plasma. The reactor comprises a tube reactor.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The process (P1) further involves pretreating the catalyst with a hydrogen gas prior to the directing step; processing the product gas to recover pure hydrogen; flowing the product gas under a vacuum pressure through a palladium/silver membrane to recover pure hydrogen; pretreating the catalyst with hydrogen prior to the placing step; and flowing the product gas under a vacuum pressure through palladium/silver membrane to recover pure hydrogen. The process (P1) involves forming a methane plasma using microwave irradiation of a methane gas under a negative pressure and at a selected microwave power, directing the methane plasma over a catalyst, and controlling a flow of the methane plasma and the microwave power to produce a product gas containing methane and hydrogen in selected volume percentages, and to remove solid carbon from the product gas in the form of solid fibrous carbon; and providing a tube reactor having microwave transparent walls in flow communication with a methane source configured to provide a flow of methane through the tube reactor, irradiating the methane using microwave irradiation at a selected microwave power to produce a flow of methane plasma, placing a catalyst in the tube reactor in the flow of methane plasma, and forming a product gas by converting a selected volume percentage of the methane to hydrogen by reaction of the methane plasma in contact with the catalyst. In the process (P1), the negative pressure is 20-200 mmHg and the microwave power is 70-160 (preferably 70-140, especially less than 120) W. The directing step is performed in a tube reactor made of a microwave transparent material. The directing step is performed with the catalyst placed on a microwave transparent holder configured to allow the methane plasma to pass through the catalyst. The controlling step is performed to produce the product gas with hydrogen (10-30 vol.%) and methane (70-90 vol.%). Forming the product gas step removes solid fibrous carbon from the product gas as a useful by-product. Forming the product gas step involves a reaction on the surface of the catalyst of CH3, CH2, CH or H with CH4, C2H2, or C2H4 and C2H6, to produce solid fibrous carbon and hydrogen. Preferred Components: The product gas comprises hydrogen (10-30 vol.%), and methane (70-90 vol.%). The product gas comprises C2H2 (2-3%), and negligible amounts of C2H4, C3H6, C3H8 and C3H4. The methane gas comprises pure methane or natural gas. The methane plasma comprises CH4, CH3, CH2, CH, C2H2, C2H4, C2H6, H2 and (e-). EXAMPLE - No suitable example given.