Catalysts for thermochemical fuel production and method of producing fuel using thermochemical fuel production

Abstract

To provide a catalyst, which is formed from a perovskite oxide, for thermochemical fuel production, and a method of producing fuel using thermochemical fuel production that is capable of allowing a fuel to be produced in a thermochemical manner. Provided is a catalyst for thermochemical fuel production, which is used for producing the fuel from thermal energy by using a two-step thermochemical cycle of a first temperature and a second temperature that is equal to or lower than the first temperature, wherein the catalyst is formed from a perovskite oxide having a compositional formula of AXO 3±δ (provided that, 0≦δ≦1). Here, A represents one or more of a rare-earth element (excluding Ce), an alkaline earth metal element, and an alkali metal element, X represents one or more of a transition metal element and a metalloid element, and O represents oxygen.

1 . A catalyst for thermochemical fuel production, which is used for producing the fuel from thermal energy by using a two-step thermochemical cycle of a first temperature and a second temperature that is equal to or lower than the first temperature,
 wherein the catalyst is formed from a perovskite oxide having a compositional formula of AXO 3±δ  (provided that, 0≦δ<1) (here, A represents any one or more of a rare-earth element (excluding Ce), an alkaline earth metal element, and an alkali metal element, X represents one or more of a transition metal element and a metalloid element, and O represents oxygen).   
     
     
         2 . The catalyst for thermochemical fuel production according to  claim 1 ,
 wherein the element A is one or more selected from a group consisting of La, Mg, Ca, Sr, and Ba, and the element X is one or more selected from a group consisting of Mn, Fe, Ti, Zr, V, Cr, Co, Ni, Cu, Zn, Mg, Al, Ga, In, C, Si, Ge, and Sn.   
     
     
         3 . The catalyst for thermochemical fuel production according to  claim 2 ,
 wherein the element A is La, and the element X is Mn.   
     
     
         4 . The catalyst for thermochemical fuel production according to  claim 1 ,
 wherein the element A is partially substituted with one or more of Sr, Ca, and Ba.   
     
     
         5 . The catalyst for thermochemical fuel production according to  claim 1 ,
 wherein the element X is partially substituted with one or more of Fe, Ni, V, Cr, Sc, Ti, Co, Cu, and Zn.   
     
     
         6 . The catalyst for thermochemical fuel production according to  claim 1 ,
 wherein the element A is La, the element X is Mn, La is partially substituted with Sr.   
     
     
         7 . The catalyst for thermochemical fuel production according to  claim 6 , wherein the substituted concentration (x; x represents an amount with an amount of La before substitution being set to 1) of Sr is 0.1 or more to less than 1.0. 
     
     
         8 . The catalyst for thermochemical fuel production according to  claim 7 , wherein Mn is partially substituted with Fe. 
     
     
         9 . The catalyst for thermochemical fuel production according to  claim 6 ,
 wherein the substituted concentration (x; x represents an amount with an amount of Mn before substitution being set to 1) of Fe that is substituted is 0.35 or more to 0.85 or less.   
     
     
         10 . The catalyst for thermochemical fuel production according to  claim 1 , wherein the element A is Ba, the element X is Ti, Ti is partially substituted with Mn. 
     
     
         11 . The catalyst for thermochemical fuel production according to  claim 10 ,
 wherein the substituted concentration (x; x represents an amount with an amount of Ti before substitution being set to 1) of Mn is more than 0 to 0.5 or less.   
     
     
         12 . A method of producing fuel using thermochemical fuel production,
 wherein the catalyst for producing a thermochemical fuel according to any one of  claim 1  is used.   
     
     
         13 . A method of producing fuel using thermochemical fuel production, which produces the fuel from thermal energy by using the catalyst for thermochemical fuel production according  claim 1  and by using a two-step thermochemical cycle of a first temperature and a second temperature that is equal to or lower than the first temperature,
 wherein the first temperature is 600 to 1,600° C., and the second temperature is 400 to 1,600° C. 
 
     
     
         14 . The method of producing fuel using thermochemical fuel production according to  claim 13 ,
 wherein the first temperature is attained by irradiation of condensed sunlight energy and heating, or by heating using waste heat.   
     
     
         15 . A method of producing fuel using thermochemical fuel production, which produces the fuel from thermal energy by using a two-step thermochemical cycle of a first temperature and a second temperature that is equal to or lower than the first temperature, the method comprising:
 a process of heating a perovskite oxide having a compositional formula of AXO 3±δ  (provided that, 0≦δ<1) to the first temperature to reduce the perovskite oxide; and   a process of bringing a raw material gas into contact with the reduced perovskite oxide and oxidizing the perovskite oxide to produce the fuel.   
     
     
         16 . The method of producing fuel using thermochemical fuel production according to  claim 15 ,
 wherein the fuel is any one of hydrogen, methane, and methanol.   
     
     
         17 . The method of producing fuel using thermochemical fuel production according to  claim 15 ,
 wherein the raw material gas includes water vapor.   
     
     
         18 . The method of producing fuel using thermochemical fuel production according to  claim 15 ,
 wherein the raw material gas includes carbon dioxide and water vapor.