Solar thermochemical fuel production system and methods of use thereof

Abstract

The invention relates to solar thermochemical fuel production systems and methods of use thereof.

What is claimed is: 
     
         1 . A method of performing thermochemical gas splitting at a reduced operating temperature, the method comprising:
 connecting a metal oxide (M y O x ) to a first electrode connected to a power source;   placing a second electrode connected to the power source in an electrolyte;   submerging the M y O x  connected to the first electrode in the electrolyte and subjecting the M y O x  and electrolyte to an increased temperature;   applying a potential to the M y O x  and electrolyte, thereby eliciting an electronic double layer at the M y O x /electrolyte interface and reducing the (M y O x ) to form a non-stoichiometric oxide (M y O x-δ ) or a stoichiometric metal oxide (M y O x-1 ); and   oxidizing the M y O x-δ  or the M y O x-1  with an oxidizing agent to regenerate the M y O x , thereby generating a gas product, heat, or a combination thereof.   
     
     
         2 . The method of  claim 1 , wherein submerging comprises submerging about 25% to about 75% of the metal oxide. 
     
     
         3 . The method of  claim 1 , wherein the electrolyte is selected from an ionic liquid, a molten salt, or a combination thereof. 
     
     
         4 . The method of  claim 3 , wherein the ionic liquid or molten salt is selected from sodium, potassium, lithium, calcium, and magnesium carbonates, chlorides, sulphates, phosphates, or a mixture thereof. 
     
     
         5 . The method of  claim 4 , wherein the molten salt is selected from NaCl, KCl, MgCl 2 , CaCl 2 ), LiCl, Na 2 SO 4 , K 2 SO 4 , Li 2 SO 4 , CaCO 3 , Li 2 CO 3 , K 2 CO 3 , or a combination thereof. 
     
     
         6 . The method of  claim 1 , wherein the metal oxide (M y O x ) is selected from ceria (CeO 2 ), SrLaMnO 3 , BaFeO 3 , Fe 3 O 4 , FeAl 2 O 4 , CoFe 2 O 4 , CoFeAl 2 O 4 , perovskites, ceria derivatives, spinel ferrites, or a combination thereof. 
     
     
         7 . The method of  claim 1 , wherein the increased temperature is selected from a temperature of about 1375° C., about 1350° C., about 1325° C., about 1300° C., about 1275° C., about 1250° C., about 1225° C., about 1200° C., about 1175° C., about 1150° C., about 1125° C., about 1100° C., about 1075° C., about 1050° C., about 1025° C., about 1000° C., about 975° C., about 950° C., about 925° C., about 900° C., about 875° C., about 850° C., about 825° C., about 800° C., about 775° C., about 750° C., about 725° C., about 700° C., about 675° C., about 650° C., about 625° C., about 600° C., about 575° C., about 550° C., about 500° C., or below about 500° C. 
     
     
         8 . The method of  claim 1 , wherein the potential is selected from less than about 0.25V, about 0.25V, about 0.5V, about 0.75V, about 1.0V, about 1.25V, about 1.50V, about 1.75V, about 2.0V, about 2.25V, about 2.5V, about 2.75V, about 3.0V, about 3.5V, about 4.0V, about 4.25V, about 4.5V, about 4.75V, about 5.0V, about 5.25V, about 5.5V, about 5.75V, about 6.0V, or greater than about 6.0V. 
     
     
         9 . The method of  claim 1 , wherein the gas product is selected from H 2 , CO, or a combination thereof. 
     
     
         10 . The method of  claim 1 , wherein the method is performed at a partial pressure of about 1 Pa, about 10 Pa, about 50 Pa, about 100 Pa, about 200 Pa, about 250 Pa, about 300 Pa, about 350 Pa, about 400 Pa, about 450 Pa, about 500 Pa, about 550 Pa, about 600 Pa, about 650 Pa, about 700 Pa, about 750 Pa, about 800 Pa, about 850 Pa, about 900 Pa, about 950 Pa, about 1000 Pa, or greater than about 1000 Pa. 
     
     
         11 . The method of  claim 1 , wherein the method has an O 2  Faradaic efficiency of about 100%, about 125%, about 150%, about 175%, about 200%, or greater than about 200%. 
     
     
         12 . The method of  claim 1 , wherein the electronic double layer produces an E-field of about 5 V/nm or greater than 5 V/nm. 
     
     
         13 . The method of  claim 9 , wherein the method has a gas production capability of about 100 to about 500 μmol gas/g metal oxide. 
     
     
         14 . An electric field enhanced CO 2  splitting system comprising:
 a reactor comprising a metal oxide, a molten salt or ionic liquid, and an electrode; and   a heat source.   
     
     
         15 . The system of  claim 14 , wherein the system further comprises a reduction heat exchanger unit, an oxidation heat exchanger unit, a reduction production separation unit, an oxidation production separation unit, heat storage tanks, a solar furnace, a turbine, one or more blowers, or a combination thereof. 
     
     
         16 . The method of  claim 14 , wherein the ionic liquid or molten salt comprises sodium, potassium, lithium, calcium, and magnesium carbonates, chlorides, sulphates, phosphates, or a mixture thereof. 
     
     
         17 . The method of  claim 14 , wherein the molten salt comprises NaCl, KCl, MgCl 2 , CaCl 2 , LiCl, Na 2 SO 4 , Li 2 SO 4 , K 2 SO 4 , CaCO 3 , Li 2 CO 3 , K 2 CO 3 , or a combination thereof. 
     
     
         18 . The method of  claim 14 , wherein the metal oxide (M y O x ) comprises ceria (CeO 2 ), SrLaMnO 3 , BaFeO 3 , Fe 3 O 4 , FeAl 2 O 4 , CoFe 2 O 4 , CoFeAl 2 O 4 , perovskites, ceria derivatives, spinel ferrites, or a combination thereof. 
     
     
         19 . The system of  claim 14 , wherein the system is an industrial system further comprising a reduction production separation unit, an oxidation production separation unit, heat storage tanks, a solar furnace, a turbine, one or more blowers, or a combination thereof. 
     
     
         20 . The system of  claim 14 , wherein the industrial system comprises the process flow diagram of  FIG.  24   .