The gasification of active carbon and coal with CO2 (the Boudouard reaction: C + CO2 = 2CO) was studied using a molten salt (the mixture of K2CO3 and Na2CO3) at 1123 K to apply this system to solar energy conversion into chemical energy. On the solar/chemical energy hybridization system to obtain CH3OH as a solar fuel, the coal with molten salt can directly gasify by the Boudouard reaction. The gasification reaction rate of active carbon and coal with CO2 into CO was enhanced by 1.5 and 3.3 times in the presence of the molten salt, respectively, compared with the absence of the molten salt. The coal gasification using molten salt was suggested to have two steps: the first step is coke production by the coal pyrolysis, and the second step is the Boudouard reaction by the catalytic effect of the alkali metal cations (K+ and Na+).