Today, hydrogen is produced in large quantities by steam reforming of hydrocarbons, generally methane. This method yields CO2 as a by-product, but no more than burning the same amount of methane. CO2 emissions, regarded as the principal cause of global climate change (King, 2004), can be managed at large-scale facilities through CO2 sequestration, which involves the capture and storage of huge quantities of CO2 underground (e.g. in depleted natural gas and oil wells or geological formations). However, CO2 sequestration is not yet technically and commercially proven. Another promising route is high-temperature pyrolysis (decomposition in the absence of oxygen) of hydrocarbons, biomass and municipal solid waste into hydrogen and (solid) carbon black, accompanied by its industrial use and/or easy sequestration. At present, the cost of this process is higher than that of steam reforming of natural gas