Conversion of carbon dioxide into methanol - a potential liquid fuel: Fundamental challenges and opportunities (a review)

As on today, the conversion of carbon dioxide (CO2) into value added chemicals including methanol using exclusively solar energy (i.e., artificial photosynthesis) has been considered as one of the top most research priorities all over the world as this process can indeed deal with (i) the mitigation of CO2 associated global warming problem, (ii) creation of highly sustainable and renewable energy resources, and (iii) development of one of the best processes to store the energy in a most convenient form of liquid fuels with sufficiently high energy density in comparison to all the existing methods of energy storage. As the CO2 sequestration process is expensive, there has been a quest for finding other alternative options. The CO2 can be converted into several value added chemicals including methanol following stoichiometric reactions, thermochemical, electrochemical, photoelectrochemical, photocatalytic, etc., routes. Methanol synthesized from CO2 can be employed directly in place of fossil fuels without disturbing the present existing energy distribution infrastructure. Further, if H-2 required for CO2 reduction is produced from water using exclusively solar energy, and methanol is produced with minimum overpotentials with the help of suitable catalytic systems, this process can be employed to address the above-mentioned three major problems. The process for converting CO2 into methanol can be developed by careful analysis and understanding of the information available on this process reported so far in the literature. Since, none of the existing review articles deals exclusively with this important process of converting CO2 into methanol, in this review article, all the information including fundamental challenges and opportunities that are associated with the conversion of CO2 into methanol following various routes has been summarized, discussed and meticulously presented by citing all the up to date relevant references. (C) 2013 Elsevier Ltd. All rights reserved.