| AVS 60th International Symposium and Exhibition | |
| Accelerating Materials Discovery for Global Competitiveness Focus Topic | Thursday Sessions |
| Session MG-ThA |
| Session: | Theory, Computation and Data-Enabled Scientific Discovery |
| Presenter: | H. Kasai, Osaka University, Japan |
| Authors: | H. Kasai, Osaka University, Japan A.A. Padama, Osaka University, Japan |
| Correspondent: | Click to Email |
We entered the 21st Century witnessing remarkable progress in Science and Technology. Novel materials and devices that were once considered the stuffs of science fiction are becoming a reality. It would not be an exaggeration to say that we are coming to the Age ofDesigner Materials. Complex materials are designed to have desired properties, with both basic and technological applications. A Designer Material has to be Functional. To realize this and to test the concepts and principles developed for realizing designer materials, we use Surfaces as our testing ground. These give access to the appropriate reduced dimensionality and means to manipulate the degree of complexity, and emergence of function.
Specifically, we were able to design catalyst for NO dissociation that is free from precious materials. NO is emitted from the combustion of fossil fuels and converts to nitric acid in the atmosphere which leads in the formation of acid rain. The dissociation of NO is known to be the rate limiting process for its reduction due to the strong N-O bond [1]. Precious metals such as Rh, Pd and Pt are efficient catalysts for such purpose but their high cost prohibits their massive production [2]. Through first principles investigation, we were able to confirm that Cu-based surface is capable of dissociating NO molecule [3, 4]. The analysis is made with reference to a clean Cu surface. In Cu(111), dissociation of NO is accompanied by a large activation barrier and NO desorption is more likely to happen. This is due to the filled d states of the Cu atoms which limits their interaction with the adsorbate. In the contrary, the local density of states profile of the d orbital of the Cu atoms in Cu2O(111) shows that the states are shifted to the Fermi level region which explains the good adsorption and easy dissociation of NO. We also found that the reaction path of NO on Cu2O surface is comparable with that of Rh surface which is characterized by a transition state lying below the reference level (surface and NOgas) [5]. Nevertheless, the activation barrier for NO dissociation is lower in Cu2O indicating the easier dissociation of NO on the alternative catalyst. Furthermore, the adsorption energy of N and O atoms from the dissociated molecule is also lower on Cu2O which is desirable for the succeeding steps in the reduction process.
References:
[1] S. Gonzalez et al., J. Catal. 239 (2006) 431.
[2] H.J. Kwon et al., Chem. Eng. Sci., 62 (2007) 5042.
[3] A.A.B. Padama et al., J. Phys.: Condens. Matter, 24 (2012) 175005.
[4] H. Kishi et al., J. Phys.: Condens. Matter, 24, 262001 (2012).
[5] H. Kasai et al., J. Jpn. Petroleum Institute, (2013) accepted for publication.