Fossil fuels are the potent source of sustainable hydrogen because of their price, availability, and convenience in transportation and storage. Carbon and hydrogen are the major constituents of the hydrocarbons, and hence serve as the promising raw material for the generation of hydrogen. There are several methods for generation of hydrogen from fossil hydrocarbons. Nevertheless, of the procedure employed for the generation of hydrogen from hydrocarbons, all the carbon (present in the hydrocarbon) will be converted into oxides of the carbon and mostly CO2. This is the major challenge toward using hydrocarbons for the production of sustainable hydrogen from hydrocarbons. The decarbonization of fossil hydrocarbons cannot be discussed without the production of CO2. This chapter will explain the use of nanotechnology in the production of sustainable hydrogen from hydrocarbons and in the mitigation of the CO2, which is produced during the process of decarbonization of fossil fuels. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021.