Decomposition of Formic Acid to H2 and CO2 in the Presence of 1,3-bis(2'-Pyridyl-Imino)-Isoindoline Iridium Complex

摘要

Our fossil fuel reserves of coal, petroleum and natural gas are limited and increasingly depleted. To fulfill the future energetic needs of an increasing population we therefore need to further develop alternative energies including solar, wind, geothermal, ocean energy but also nuclear energy. In fact we do not have an energy problem. The sun can provide us with all the energy we need. The problem is how to collect this energy and furthermore how to store it. All of the alternative energy sources, except biomass, produce only electricity which is difficult to store on a large scale. Batteries are bulky and expensive and other methods of storage such as fly wheels, compressed air and pumped hydro have limited capacity. One of the possibility is to store this energy in the form of chemical bonding in a gas or liquid such as hydrogen, methanol and formic acid. Hydrogen is a very good fuel, producing only water upon combustion. Hydrogen, a highly explosive gas is however itself difficult to store and transport and has first to be compressed at high pressure or liquefied at -253 °C. An easy to handle liquid would therefore be preferable as an energy carrier. Formic acid has been proposed as such a carrier and can be produced from CO2 and water over an appropriate catalyst. An electrochemical route from CO2 and water is also possible. The obtained formic acid can be easily stored and transported. Through its decomposition by decarboxylation it can be used as a convenient source for H2.