The invention relates to a process to convert hydrocarbons into hydrogen and a separate carbon phase, whereby in step a) the hydrocarbons are contacted with a molten salt, preferably comprising Zinc Chloride, at temperatures preferably above 500° C. and in step b) a solid or liquid carbon phase is separated from the molten salt at a lower temperature, preferably below 150° C. The molten salt is then preferably re-heated to the desired temperature and recycled to step a). The process avoids the emission of CO2, making the hydrogen produced in this way a zero CO2 emission fuel and which also produces a carbon product produced having a use value.