کاهش الکتروشیمیایی دی اکسید کربن برای سنتز سوخت سبز Electrochemical reduction of CO2 for synthesis of green fuel

INTRODUCTION Energy requirements are continuously increasing and putting a lot of pressure on finite conventional energy resources. According to the projections of International Energy Outlook, natural gas, coal, and oil will be used for more than three-fourths of the total world energy consumption by 2040.1 Since fossil fuels are limited as well as responsible for environmental issues, alternate sources need to be explored for sustainable energy supply. As per the recent report of the Intergovernmental Panel on Climate Change (IPCC), fossil fuels should be phased out completely in power generation by 2100 to keep their negative environmental impacts in check.2 The increased use of fossil fuels has resulted in a higher CO2 concentration in the atmosphere, which has crossed the level of 400 ppm.3–5 On the other hand, natural sinks for CO2 sequestration, such as forest cover, are depleting. According to World Resources Institute, ~80% of the earth’s forest cover has already vanished due to deforestation in past century.6 It shows that natural CO2 absorbers are being deteriorated at a fast rate, resulting in the increased carbon balance in the atmosphere. The widening gap between emitted CO2 and sequestered CO2 is an indicator that the existing sink needs to be assisted by some kind of artificial process that can perform the same function as the trees/forests. Therefore, scientists are trying to develop such processes that can not only fulfill the rising energy demands by the production of fuels but, at the same time, can also help in minimizing the excess CO2 of the atmosphere. In this aspect, the electrochemical reduction of CO2 (ERC) has become one of the most promising methods, which may convert CO2 using renewable energy (solar or wind) to valueadded chemicals that can serve the purpose of fuels. It has been conceptualized and accepted that plant functions can actually be mimicked using ERC.