This SBIR Phase I project will convert (recycle) CO2 into useful and economically important by-products (i.e., industrial feed stocks) using a nano crystalline anatase (TiO2) photo catalyst with a high surface area. Anatase is a well known photo-catalyst. The co-founders of the Nanospring platform hold a patent on the project catalyst system that has shown the ability to convert CO2 to methanol (using a gas-to-gas continuous reactor, patent applied for), and, possibly, formic acid and formaldehyde at room temperature. Specifically, the research will develop and test a filter-type system that could be retrofitted in-line of the exhaust stacks at power and industrial plants. This approach is termed Carbon Capture and Recycle. The Research Plan addresses three objectives by three sets of tests at the laboratory scale: 1) evaluation of the catalytic properties of the TiO2-coated silica Nanosprings mat formed on a 100 um glass frit; 2) optimization of the catalyst coating; and 3) evaluation and testing of the prototype catalyst filter system using 'real world' flue gas emissions.
The broader/commercial impact of the proposed project will be the potential for successful commercial application. There is a need for technologies that will reduce the carbon emitted to the atmosphere from coal-fired plants, and the project includes support from a large power company. The technology is particularly competitive for power plants that are long distances from geologically suitable CO2 storage sites. The process not only will be continuous flow but also could be by-product "tuneable", i.e., generating a variety of chemicals by controlling operating conditions. Based on the 30% efficiency identified in the preliminary laboratory testing, the process could convert one metric ton of CO2 into 0.245 metric tons of methanol.
GoNano Technologies has pursued the commercialization of the Carbon Capture and Recycling technology. This report describes the progress made in that direction as part of the NSF funded SBIR phase I grant. Optimization of the photocatalyst that can be coated on the NanospringsTM mat was performed by studying the CO2 conversion efficiencies into products. A more efficient and easily scalable solar panel like reactor that enables the exact quantification of the reaction efficiency was designed. The most economical reaction types that would elicit industry interest in CO2 photoreduction were chosen to characterize the photocatalysts produced at GoNano. It has been proven that for consistent results CO2 has to be dissolved in water to form carbonic acid. The first type of reaction where CO2 was dissolved in water was converted into methanol using the TiO2 coated Nanosprings grown on a glass fiber mat. Conversion efficiency in the range of 3-5% of the dissolved CO2 conversion was measured. In the second type of reaction, 1% methanol solution was added to the CO2 solution and the photoreduction experiments carried out. A higher conversion efficiency of dissolved CO2 of 12% was observed in the presence of methanol. A commercial CCR plant could thus have two stages where methanol from the first stage could be used for better photoreduction of CO2 in the subsequent stage. The in-house developed ALD system had to be upgraded to enhance the quality of the photocatalyst coatings on the Nanosprings. With better valve mechanisms, better temperature controls and a new sample holder that enhances the precursor contact with the Nanosprings mat, GoNano has been able to produce samples that have a much lower Cl content. The photoactivity of these improved samples has been measured by the photodegradation studies on Alizarin red dye. Experiments to improve the conversion efficiencies were tried by depositing nanoparticles of ZnO and co-doping TiO2 by ZnO. As a step towards achieving maximum catalyst activity, studies on the photooxidation of methyl tert-butyl ether were performed. It was proven that the TiO2 on the Nanosprings 3-4 times faster than commercially available TiO2 particles. A commercial CCR system will have to involve a multitude of partners like carbon emitters, carbon capture systems, GoNano, feedstock chemical distributors. There also needs to be a governmental push towards utilizing carbon. With more development GoNano will be able to wedge with other carbon utilization technologies to tackle the global CO2 problem.
