Improving electronic structure methods to predict nano-optoelectronics and nano-catalyst functions.

Nielsen, Ida Marie B. ; Marzari, Nicola (Massachusetts Institute of Technology) ; Shelnutt, John Allen ; Kulik, Heather J. (Massachusetts Institute of Technology) ; Medforth, Craig John (University of New Mexico, Albuquerque, NM) ; Leung, Kevin

Sandia National Laboratories

关键词: Electronic Structure;    Transition Elements;    Nuclear Energy;    Water;    Redox Potential;   

DOI  :  10.2172/1001019
RP-ID  :  SAND2009-6425
RP-ID  :  AC04-94AL85000
RP-ID  :  1001019

美国|英语

来源: UNT Digital Library

【 摘 要 】

This report focuses on quantum chemistry and ab initio molecular dynamics (AIMD) calculations applied to elucidate the mechanism of the multi-step, 2-electron, electrochemical reduction of the green house gas molecule carbon dioxide (CO{sub 2}) to carbon monoxide (CO) in aqueous media. When combined with H{sub 2} gas to form synthesis ('syn') gas, CO becomes a key precursor to methane, methanol, and other useful hydrocarbon products. To elucidate the mechanism of this reaction, we apply computational electrochemistry which is a fledgling, important area of basic science critical to energy storage. This report highlights several approaches, including the calculation of redox potentials, the explicit depiction of liquid water environments using AIMD, and free energy methods. While costly, these pioneering calculations reveal the key role of hydration- and protonation-stabilization of reaction intermediates, and may inform the design of CO{sub 2}-capture materials as well as its electrochemical reduction. In the course of this work, we have also dealt with the challenges of identifying and applying electronic structure methods which are sufficiently accurate to deal with transition metal ion complex-based catalyst. Such electronic structure methods are also pertinent to the accurate modeling of actinide materials and therefore to nuclear energy research. Our multi-pronged effort towards achieving this titular goal of the LDRD is discussed.