Grantee Research Project Results
Computational and Experimental Investigation of Catalyst Deactivation to Design Sulfur-Resistant Emissions Oxidation CatalystsEPA Grant Number: FP917501
Title: Computational and Experimental Investigation of Catalyst Deactivation to Design Sulfur-Resistant Emissions Oxidation Catalysts
Investigators: Sharma, Hom N
Institution: University of Connecticut
EPA Project Officer: Just, Theodore J.
Project Period: August 23, 2012 through August 22, 2015
Project Amount: $126,000
RFA: STAR Graduate Fellowships (2012)
Research Category: Academic Fellowships , Fellowship - Chemical Engineering
During diesel combustion in the engine, sulfur in the diesel is oxidized to sulfur oxides (SOx), which can block the active sites on the DOC (site poisoning) and also alter the chemical characteristics through sulfation. To identify sulfur-resistant catalyst materials for DOCs, one first needs to understand how SOx interacts with the catalyst, how metal and support of the catalyst get sulfated, how fast the sulfation chemistry is and which strategy should be used to screen promising materials.Approach:
In this research, quantum mechanical Density Functional Theory (DFT) will be utilized to estimate the kinetic parameters for bimetallic Pt-Pd catalyst, SOx chemistry, alumina support sulfation and PdO sulfation, consistent with the aforementioned technical challenges. This information will be incorporated into a kinetic model for emissions oxidation to predict the DOC deactivation over time. Finally, this study will explore the effect of catalyst doping on sulfation kinetics to identify promising sulfur resistant materials, followed by experimental validation.Expected Results:
Catalyst deactivation due to sulfur is a complex phenomenon that involves interactions of sulfur with metal catalysts, catalysts’ support and DOC primary chemistry. This research will provide information of reaction kinetics for the underlying sulfation chemistry of DOC. Furthermore, it will help to overcome challenges of developing a novel catalyst screening tool and identify the improved sulfur resistant DOC materials.
Potential to Further Environmental/Human Health Protection
Engine emissions will continue to pose a serious threat to human health and the environment. Because the protection of human health and the environment from toxic emissions from engines depends on the robustness of after-treatment catalysts, a fundamental understanding of reaction kinetics and catalysts’ deactivation chemistry is crucial to designing such materials. The proposed research findings will have applications beyond the DOC system, especially for emissions after-treatment components such as Selective Catalytic Reduction (SCR) and catalytic Diesel Particulate Filter (cDPF). Furthermore, engines and after-treatment system manufacturers will benefit from the research findings as they are required to meet the standards, whereas policy makers will be able to implement the appropriate regulations.