Hydrogenation of CO2 Current approach to reduce CO2 includes capturing and storing from facilities across the world. However, storage poses technical and economic barriers preventing global scale application. To utilize CO2 at the point source, CO2 hydrogenation is a realistic and practical approach. Conventional hydrogenation reduces unsaturated organic compounds by addition of H2. One method of CO2 hydrogenation is via the methanol pathway. Methanol can be used to produce long chain hydrocarbons. Some barriers of CO2 hydrogenation includes purification of captured CO2, H2 source from splitting water and energy inputs for hydrogenation. To overcome these barriers, we can further develop green H2 technology and encourage catalyst research at industrial and academic level. For industrial applications, CO2 is often converted to methanol. Until now, much progress has been made for CO2 to C1 molecules. However, CO2 to high value molecules still face many roadblocks and the future of CO2 hydrogenation depends on the advancement of catalytic technologies. Metal hydrides Metal hydrides, such as MgH2, NaAlH4, LiAlH4, LiH, LaNi5H6, TiFeH2, ammonia borane, and palladium hydride represent sources of stored hydrogen. Again the persistent problems are the % weight of H2that they carry and the reversibility of the storage process. Some are easy-to-fuel liquids at ambient temperature and pressure, whereas others are solids which could be turned into pellets. These materials have good energy density, although their specific energy is often worse than the leading hydrocarbon fuels. LiNH2, LiBH4, and NaBH4. An alternative method for lowering dissociation temperatures is doping with activators. This strategy has been used for aluminium hydride, but the complex synthesis makes the approach unattractive. Proposed hydrides for use in a hydrogen economy include simple hydrides of magnesium or transition metals and complex metal hydrides, typically containing sodium, lithium, or calcium and aluminium or boron. Hydrides chosen for storage applications provide low reactivity (high safety) and high hydrogen storage densities. Leading candidates are lithium hydride, sodium borohydride, lithium aluminium hydride and ammonia borane. A French company McPhy Energy is developing the first industrial product, based on magnesium hydride, already sold to some major clients such as Iwatani and ENEL. Reversible hydrogen storage is exhibited by frustrated Lewis pair, which produces a borohydride. The phosphino-borane on the left accepts one equivalent of hydrogen at one atmosphere and 25 °C and expels it again by heating to 100 °C. The storage capacity is 0.25 wt%. Aluminium Hydrogen can be produced using aluminium