This chapter starts with a brief introduction describing the energy challenges and biomass feedstocks to produce biofuels. Next, biofuels generations are discussed and how the use of nanotechnologies helps to obtain renewable energy, overcoming the pollution associated with the generation and use of fuels. Specifically, it is shown that it is possible to produce first- and second-generation biofuels from the conversion of biomass. Finally, the conversion of lignocellulosic biomass through two thermochemical processes is discussed. In particular, the chapter presents the pyrolysis and gasification routes and shows the different catalytic materials used in the production of second-generation biofuels.