1 Electronic Supplementary Information (ESI) STEP Cement: S olar T hermal E lectrochemical P roduction of CaO without CO 2 emission (Chemical Communications) Stuart Licht, *,a Hongjun Wu, a,b Chaminda Hettige, a Baohui Wang, a,b Joseph Asercion, a Jason Lau, a Jessica Stuart a 5 *CORRESPONDING AUTHOR EMAIL ADDRESS: slicht@gwu.edu a Department of Chemistry, George Washington University, Washington, DC 20052, USA. b Present address: Northeast Petroleum University, Daqing, P. R. China 10 Content Expanded experimental details: Thermodynamic calculations Chemicals, materials, electrolysis configurations 15 Carbonate stability Solubility analyses and calcium oxide product analyses Economic assessment Addendum: STEP theoretical background Addendum: STEP solar to chemical energy conversion efficiency 20 Supplementary References Cement production accounts for 5-6% of all anthropogenic CO 2 emissions. Massive CO 2 emissions also occur with the CaO formed from CaCO 3 for purifying iron and aluminum, for agriculture, glass, paper, 25 sugar, calcium carbide, and acetylene production, to scrub SO 2 from smoke stacks, to soften water or to remove phosphates from sewerage. 12,13 ClimateCentral.org recently wrote that no other sector has such a high potential for drastic emission reductions, and while other processes are being explored to sequester cement’s CO 2 , none eliminate it. Society consumes over 3x10 12 kg of cement annually, and the cement industry releases 9 kg of CO 2 for each 10 kg of cement produced. An alternative to this CO 2 intensive 30 process is needed. The majority of CO 2 emissions occurs during the decarbonation of limestone (CaCO 3 ) to lime (CaO) described in equation 1, and the remainder (30 to 40%) from burning fossil fuels, such as coal, to heat the kiln reactors to ~900°C, eq. 2: 1-3 In this Chemical Communications and Electronic Supplementary Infromration, we show a new thermal 35 chemistry, based on anomalies in oxide solubilites, to generate CaO, without CO 2 emission, in a high throughput, cost effective, environment conducive to the formation of cement. Expanded experimental details: 40 Thermodynamic calculations Electrolysis potentials are calculated from the thermochemical enthalpies and entropies of the reactants. 14,15 Chemicals, materials, electrolysis configurations Lithium carbonate was utilized (Li 2 CO 3 , Alfa Aeasar, 99%), lithium oxide (Li 2 O (99.5%, Alfa Aeasar), sodium 45 carbonate (Na 2 CO 3 , Avantor 99.5%), potassium carbonate (K 2 CO 3 , Avantor 99%), Ni foil (pure Ni 200 McMaster 9707K59), Ni wire (1 mm diameter, 99.5%, Alfa Aeasar), steel wire (14 gauge), 25 and 75 µm nickel and steel sheet (McMaster 95481, 97057), and various crucibles: nickel (Alfa Aeasar 35904), steel (VWR 82027), and high purity alumina (99.6% AdValue Technology); crucibles were encased in high temperature foam insulation (McMaster 9353). 50 Electronic Supplementary Material (ESI) for Chemical Communications This journal is © The Royal Society of Chemistry 2012