Theoretical Studies of Catalysis at ORNL
Traditional catalytic science is based on the trial-and-error approach since its advent. It is rapidly becoming inadequate as the demand for new catalysts grows with emerging technologies and increasing energy/material cost and environmental regulations. Theory as enabled by modern computation is an integral component of the new, rational approach to catalysis. Theoretical insight has already led to the discovery of new/improved catalysts for a number of reactions in recent years, even including well-established processes such as the electrochemical oxygen reduction and hydrogen evolution reactions, the methanation reaction, and the hydrodesulfurization reaction.
ORNL has programs focused upon computational catalysis. Within the Catalytic Nanosystems group and the Surface Chemistry and Heterogeneous Catalysis group, there is on-going work to investigate heterogeneous catalytic reactions at the atomic and molecular level using first-principles electronic structure-based methods. This work involves collaborative efforts with groups both inside and outside ORNL and includes fundamental as well as applied catalytic processes. Current work is supported by DOE-BES, the User program at the Center for Nanophase Materials Sciences as well as industrial sponsors.
In the area of applied computational catalysts, the ORNL’s Fuels, Engines, and Emissions Research Group (FEERG) at the National Transportation Research Center has several unique catalysis computational modeling capabilities covering a range of scales from micron-sized powders up to integral monolith reactors and full-scale engine-aftertreatment systems. In these activities, FEERG staff members utilize a range of computational software including both in-house and commercial codes for single and multi-phase reacting turbulent and laminar flows (such as Fortran and MatLab device models, MFIX), in-cylinder combustion (such as KIVA), and integrated engine-aftertreatment systems performance (such as GTPower, WAVE, and PSAT). All of these codes are designed to incorporate either micro- or global catalytic reaction kinetics determined in the experimental catalyst characterization facilities in FEERC or at companion ORNL facilities such as the High-Temperature Materials Laboratory (HTML). In addition, the codes typically include coupling of heat, mass, and momentum effects with the reaction chemistry as they would occur in practical applications. Members of FEERG coordinate the activities of the Crosscut Lean Exhaust Emissions Reduction Simulation (CLEERS) collaboration on applied emissions catalysis modeling for DOE’s Office of Vehicle Technologies.
The Physical Chemistry of Materials group is actively pursuing "Catalyst by Design Approach". In this approach, a large number of candidate materials are examined by theoretical modeling and the only the most promising candidates are synthesized, characterized, and evaluated experimentally. The focus of this research is on automotive applications and the work is supported by DOE-EERE-OFCVT.
Oak Ridge National Laboratory also has several projects in the area of enzyme catalysis. The goal of these projects is to provide a fundamental, molecular-level description of catalytic processes and determine origin of catalytic effects. The CMB teams try to integrate high-performance computer simulation, neutron scattering and other techniques to harness catalytic powers of enzymes for different purposes or to discover potential ways for inhibition of their activities. A unique feature of the CMB projects is the involvement of and collaboration with a number of leading experimental laboratories. The work on enzymes spans the Biological and Environmental, Computational and Neutron Scattering Directorates at ORNL. Some of the CMB research activities on enzyme catalysis are summarized below.
ORNL has many computer resources from the high-performance Oak Ridge Institutional clusters to the supercomputers at ORNL’s National Center for Computational Sciences that support computational catalysis efforts.