Research

Some of the many projects that NRG group members currently work on include:

Metal-Organic Frameworks (MOFs) as Heterogeneous Catalyst Supports


• NRG frequently works to bring unconventional supports into the heterogeneous catalysis field 

MOFs offer the potential of isolation and uniform distribution of catalytic active sites

 One reaction includes hydrogen peroxide activation via MOF-supported Lewis-acid sites



The effect of support morphology on CoxOy/CeO2 catalysts for the reduction of NO by CO 

• Cerium oxide is an excellent support leading to complex redox behavior that is dependent on synthesis method 

• We are exploring how changing the shape of cerium oxide nanoparticles changes the properties of supported cobalt oxide 

• Different surface planes and defect concentrations in the support change the cobalt oxide reducibility and activity for NO reduction, with applications in reducing automotive emissions.



Synthesis of shape-selective oxide catalysts:

• We are developing new shape-selective, all-oxide catalysts that we call nanobowls

• These materials consist of < 2 nm cavities on the surface of an oxide carrier particle. They may be of a variety of compositions. 

• The nanobowl concept is being extended to control selectivity and improve stability of a number of catalyst classes including supported metal nanoparticles and acid catalysts.

• Variations include developing novel methods to entrench or to overcoat active sites in collaboration with other research                                                                                                      groups.
 

High Temperature Entrenchment of Metal Nanoparticles on Silica for Stabilization of Heterogeneous Catalysts

 We currently investigate the high-temperature behavior of transition metal nanoparticles on modified silicon wafers using AFM 

 Their stability studies help us screen catalysts for reactions of commercial significance   




Regioselective addition of alcohols to epoxides for polyol synthesis


• Selective ring-opening of epoxides leads to a number of useful products or synthons and is a useful probe reaction for understanding acid catalysts.

• We use computational techniques and experimental data to develop homogeneous and heterogeneous regioselective catalysts and to optimize reaction conditions.




Tandem Orthogonal Catalytic Systems (with Prof. Gray and Prof. Wells)
 

• Combining thermocatalysis with other catalytic modalities (photocatalysis, electrocatalysis, biocatalysis) offers many new and exciting opportunities


• Microbial electrosynthesis cells can use a variety of species in wastewater to produce dilute aqueous H2O2, which can be utilized by a thermocatalyst operated for downstream chemicals production.


• Photocatalysts or photochemical initiation can generate reactive intermediates that react further on conventional thermocatalytic sites. 


Metal sulfides for dehydrogenation
 


• Metal sulfides are known hydrogen evolution catalysts and are used frequently in hydrogenation/hydrogenolysis (hydrotreating)


• Metal sulfides are much less studied for dehydrogenation.


• We have shown them to be active for alkane dehydrogenation and alcohol dehydrogenation and acceptorless dehydrogenative coupling




Supported copper oxide as a new catalyst for oxidative dehydrogenation
 
 
 Supported copper oxide is often inactive or is prone to complete reduction to metal at high loadings

• At low loadings, it is an active material for oxidative dehydrogenation with significant support effects and differences from other supported oxides

• We are also learning to understand support effects via Lewis acidity dye probes.




SiO2 deposition on metal oxides to tune solid acid behavior


Metal oxide catalysts including zeolites (SiO2-Al2O3) usually contain a mixture of sites and pore structures

• Targeted catalyst design is in high demand for application in natural gas and biomass conversion processes

• NRG has developed a liquid phase SiO2 overcoat technology and applied this to Al2O3 and Ti-SiO2 catalysts