Selective Heterogeneous Catalysis
EMSL Project ID
19794
Abstract
(Abstract from PNNL Lab Fellows LDRD proposal)[In this project we will create a "single site" catalysis capability at PNNL by robustly tethering catalytic centers to surfaces . The result will combine the selectivity of homogeneous systems with the stability and utility of heterogeneous systems. Development of methods to tether stable organometallic catalyst sites to surfaces is a pivotal issue. Further, it may be possible to direct the catalytic processes using the geometry of the nanostructured support. Selectively modifying high surface area materials (nanoporous silica and carbon nanotubes) through robust anchoring of catalytic centers opens entirely new areas for the study of fundamental catalytic processes. The creation of a surface of identical sites will allow the measurement of the catalytic properties of arrays of identical chemical centers without the need for direct monitoring at a single site. Success in this effort will represent a major breakthrough for basic understanding of catalysts while leading directly to applications where the ease of recovery and stability of heterogeneous catalysts is coupled with the design flexibility of homogenous systems. Control and rational design of durable catalysts are of great importance to both the DOE and to the chemical industry. Example applications where catalyst of improved stability and selectivity would be valuable are broad and include biomaterials processing, hydrogen production, waste remediation and artificial photosynthesis for zero net carbon fuel production.]
Specifically, this project involves the linking of organometallic catalytic centers (eg rhodium chloro carbonyl) to the surface of high surface area materials (eg carbon nanotubes and mesoporous silica) using organic tethers. The oxidation state of the attached metal, the total loading of metal centers onto the surface, and the components of the ligands and tethers are all very relevant to the performance of the catalytic system. EMSL capabilities including XPS, XRD, and NMR would be valuable for determining these characteristics of the newly developed materials. Additionally, knowledge of the state(s) of the surfaces including porosity, chemical content, and structure, are important for the designing and subsequent control of reaction sites to influence reaction rates and products. EMSL capabilities including SEM, TEM, XPS, XRD and TGA-MS would aid in acquiring this knowledge.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2006-08-08
End Date
2009-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members