World’s increasing energy demand can be easily met by the fossil fuel reserves for next several decades only if the carbon dioxide (CO2) emission from the power plants can be reduced or mitigated. The techniques currently pursued to meet this challenge can be divided into two broad categories: CO2 sequestration (geological, oceanic, and terrestrial), and CO2 conversion into useful materials such as fuels or chemical compounds. The energy cost involved for either of the techniques mentioned above has kept them from being deployed as a scalable process. Photocatalytic conversion of CO2 is an attractive option but not practical yet due to low conversion rate and high cost of precious metal catalyst used. We have succeeded in reducing CO2 by carbon at room temperature using localized surface plasmon (LSP) energies from aluminum (Al) plasmonic nanoparticles excited by electrons. Al nanoparticles, ranging from 30 nm to 300 nm, were loaded on either amorphous carbon film or polycrystalline graphite support and introduced in an environmental transmission electron microscope (ETEM), equipped with a monochromated source and operated at 80 kV, to characterize and estimate the CO2 reduction rate. In CO2 environment of ≈ 50 Pa, the carbon was observed to etch away near Al nanoparticles at 10 times faster rate than in the regions away from the particles but irradiated by the same electron beam dose. We believe that the carbon etching by CO2 proceeds according to the reverse Boudouard reaction (CO2 + C → 2CO), i.e. reducing CO2 to carbon monoxide (CO). We estimate CO2 reduction rate by measuring carbon etching rate as a function of number of Al nanoparticles, CO2 pressure, and LSP resonance amplitude. Complete analysis, mechanism and scalability details will be presented. Potentially the reduction can be achieved using sunlight to excite LSP resonances on Al particles and that will make this cost-effective process scalable at industrial level requiring only sunlight and earth-abundant Al and C for CO2 reduction.

Room-temperature reduction of carbon dioxide

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.