Very recently, Prof. Robert H. Crabtree from Yale University: New Haven, CT, US, wrote a scientific letter on “Alternate Strategies for Solar Fuels from Carbon Dioxide” in ACS Energy Letters [1] .   In his letter, he mentioned that the timing mismatch between the supply and demand for solar electricity would require energy storage, for which conversion to a storable chemical fuel is one option. Beyond that, sectors such as marine navigation, aviation, etc. may still need liquid fuels, exported from the solar facility. These might also serve as one input into a future renewable chemicals industry.   Dihydrogen is hard to store; therefore, converting CO 2 into liquids such as methanol or ethanol is a leading option and also methanation to form “solar methane”.   U. Ulmer et al., mentioned in their recent review article titled on “Fundamentals and applications of photocatalytic CO2 methanation” [2] , that is one of the recent research efforts, “solar meth...