Photoelectrochemical Reduction of CO2 and Electrochemical Oxidation of CO

The disparity between energy demand and fossil fuel sources is increasing very fast and the air quality is deteriorating recklessly with the exponential growth of the world population. These force us not only to think about the greener alternate of fossil fuel as the energy source as soon as possible but also immediate removal of the pollutants which are already accumulated in the air in a large excess. CO and CO₂ are the two among the major pollutants present in air, both of which mainly originate due to the partial and full combustion of the fossil fuels, respectively. CO has immediate hazards to our health, whereas CO₂ acts as a greenhouse gas and consequently the major contributor to the global warming. Therefore, photooxidation of CO and photoreduction of CO₂ have become inevitable to make the air free of CO and CO₂ . In addition, the photoreduction of CO₂ to high energy density fuels can potentially be a route to shun the heavy use of fossil fuel. This chapter includes the important outcomes so far, major challenges associated and future prospects as well. This will be broadly divided in two sections of photochemical oxidation of CO and photoelectrochemical reduction of CO₂ .