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Title: SOLAR THERMOCHEMICAL WATER SPLITTING: ADVANCES IN MATERIALS AND METHODS.

Abstract

Abstract not provided.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Fuel Cell Technologies Office (EE-3F)
OSTI Identifier:
1394883
Report Number(s):
SAND2016-9233C
647505
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Proposed for presentation at the ECI Nonstoichiometric Compounds VI held September 5-8, 2016 in Santa Fe, NM.
Country of Publication:
United States
Language:
English

Citation Formats

McDaniel, Anthony H., Miller, James E., Debora Barcellos, Michael Sanders, Jianhua Tong, and Ryan O?Hayre, Colorado School of Mines, Golden, CO, Nadia Ahlborg, Chirranjeevi Balaji Gopal, and William Chueh, Stanford University, Stanford, CA, and Antoine Emery and Christopher Wolverton, Northwestern University, Evanston, IL. SOLAR THERMOCHEMICAL WATER SPLITTING: ADVANCES IN MATERIALS AND METHODS.. United States: N. p., 2016. Web.
McDaniel, Anthony H., Miller, James E., Debora Barcellos, Michael Sanders, Jianhua Tong, and Ryan O?Hayre, Colorado School of Mines, Golden, CO, Nadia Ahlborg, Chirranjeevi Balaji Gopal, and William Chueh, Stanford University, Stanford, CA, & Antoine Emery and Christopher Wolverton, Northwestern University, Evanston, IL. SOLAR THERMOCHEMICAL WATER SPLITTING: ADVANCES IN MATERIALS AND METHODS.. United States.
McDaniel, Anthony H., Miller, James E., Debora Barcellos, Michael Sanders, Jianhua Tong, and Ryan O?Hayre, Colorado School of Mines, Golden, CO, Nadia Ahlborg, Chirranjeevi Balaji Gopal, and William Chueh, Stanford University, Stanford, CA, and Antoine Emery and Christopher Wolverton, Northwestern University, Evanston, IL. 2016. "SOLAR THERMOCHEMICAL WATER SPLITTING: ADVANCES IN MATERIALS AND METHODS.". United States. doi:. https://www.osti.gov/servlets/purl/1394883.
@article{osti_1394883,
title = {SOLAR THERMOCHEMICAL WATER SPLITTING: ADVANCES IN MATERIALS AND METHODS.},
author = {McDaniel, Anthony H. and Miller, James E. and Debora Barcellos, Michael Sanders, Jianhua Tong, and Ryan O?Hayre, Colorado School of Mines, Golden, CO and Nadia Ahlborg, Chirranjeevi Balaji Gopal, and William Chueh, Stanford University, Stanford, CA and Antoine Emery and Christopher Wolverton, Northwestern University, Evanston, IL},
abstractNote = {Abstract not provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 9
}

Conference:
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  • Abstract not provided.
  • Additional results on the low temperature reactions for reforming CuO from Cu/sub 2/O are presented. These results pertain to the following reaction in the copper oxide cycle: I/sub 2/ + Cu/sub 2/O + Mg(OH)/sub 2/ = 2CuO + MgI/sub 2/(aq) + H/sub 2/O at 448/sup 0/K, ..delta..G/sup 0/ = -78.5. 4 references, 4 figures.
  • Several oxides can be decomposed to oxygen and a lower oxide at temperatures that might be feasible with a solar heat source. Heat might be directly transmitted to the solid through an air window, rather than quartz, with release of oxygen to the atmosphere. The cycle utilizing CuO, I/sub 2/, and Mg (OH)/sub 2/ is similar to the previous Co/sub 3/O/sub 4/ - CoO cycle. We are concentrating on the reformation of CuO. At 448 K the rate is favorable; for example, the yield rises about linearly with time to 92% at 1.17 h and more slowly thereafter. The onlymore » difficulty is the formation of CuI as a metastable intermediate. The oxidation of CuI is thermodynamically very favorable, but its rate limits completion. Excess Mg(OH)/sub 2/ appears to increase the rate but not to the point where IO/sub 3//sup -/ oxidation of CuI competes with oxidation of Cu/sub 2/O. Nevertheless, the batch runs suggest that about 98% of the maximum possible MgI/sub 2/ could be formed. Cuprous iodide complexes formed in the concentrated MgI/sub 2/ may give the necessary improvement by providing a solution path for their oxidation by iodate. Work of others pertaining to the cycle is briefly discussed.« less
  • Abstract not provided.
  • The concept of utilizing oxide decompositions in advanced thermochemical hydrogen cycles for solar heat sources is introduced. It has particular interest in allowing direct transmission of energy to the process through an air window. A cycle for the Co/sub 3/O/sub 4/-CoO pair would be, schematically: (1) Co/sub 3/O/sub 4/ = 3CoO + 1/2 O/sub 2/; (2) I/sub 2/(s,1) + Mg(OH)/sub 2/ + 3CoO = MgI/sub 2/(aq) + Co/sub 3/O/sub 4/ + H/sub 2/O(1); (3) H/sub 2/O + MgI/sub 2/(aq) = MgO + 2HI; (4) 2 HI = H/sub 2/ + I/sub 2/; and (5) MgO + H/sub 2/O = Mg(OH)/submore » 2/. Reaction (2) should give a high concentration of MgI/sub 2/ that would be favorable for (3). The solutions would also contain iodine dissolved as polyiodide, partly offsetting this advantage. Preliminary results indicate that reaction (2) is slow at 150/sup 0/I/sub 2/ (4); and Mg. It is surmised that the mechanism of (2) consists of the iodine disproportional reaction (6), followed by reaction (7); (6) I/sub 2/(s,1) + Mg(OH)/sub 2/ = 5/6 MgI/sub 2/(aq) + 1/6 Mg(IO/sub 3/)/sub 2/(aq) + H/sub 2/O(1); and (7) 1/6 Mg(IO/sub 3/0/sub 2/(aq) + 3 CoO = 1/6 MgI/sub 2/(aq) + Co/sub 3/O/sub 4/. Other workers have found (6) to be relatively fast and with a good yield at 150/sup 0/C. We have found reaction (7) to be sufficiently slow at 150/sup 0/C to account for the slowness of (2). The yield of (7) was found to be proportional to the square root of the time, which suggests that iodate must diffuse through an adherent, accumulating Co/sub 3/O/sub 4/ layer. Since (7) is much faster when Mg(IO/sub 3/)/sub 2/ is replaced by KIO/sub 3/, the magnesium ion may catalyze formation of an adherent Co/sub 3/O/sub 4/ spinel layer or enter into the structure of the layer. The reactivity of CoO in the KIO/sub 3/ analog of (7) is greatly decreased by exposure to high temperature.« less