Electrochemical conversion of carbon dioxide into renewable fuel chemicals - The role of nanomaterials and the commercialization

The conversion of waste-stream greenhouse carbon dioxide (CO2) gas into value added chemicals and solar fuels using solar energy or electricity derived from sunlight is popularly known as artificial photosynthesis (AP). This latter process can indeed address the problems related to (i) the CO2 associated global warming, (ii) energy crisis due to the depletion of fossil fuels, and (iii) energy (and/or electricity) storage in high energy density chemical fuels. There are six types of processes (i.e., reactions) available to convert CO2 into value added chemicals; namely, (i) stoichiometric (also called as redox and neutralization reactions), (ii) thermo-chemical, (iii) biochemical (for e.g., algae production), (iv) photo catalytic, (v) photoelectrochemical (PEC) and (vi) electrochemical. Based on today's state-of-the-art on this subject, only electrochemical routes can be fully developed in such a way that the commercial plants can be established based on this process to produce renewable fuel chemicals from CO2, water and electricity (derived from sunlight or from any other renewable energy). Of late, the nano-structured materials (including nanoparticles, NPs) have found to play a significant role in improving the reaction efficiency and rate of reaction of this electrochemical conversion of CO2 into fuel chemicals. In this article, (i) the role of CO2 in dealing with the energy and global warming related problems, (ii) the fundamental understandings of electrochemical reduction of CO2 (ERC), (iii) the role of nanomaterials and reverse microbial fuel cells (R-MFC) on ERC, and (iv) the information about the already commercialized ERC processes have been presented and discussed while citing all the up-to-date relevant references. (C) 2016 Elsevier Ltd. All rights reserved.