Catalysis – An Indispensable Tool

Meeting Program — September 2015

Sourav Sengupta
Sourav Sen­gup­ta
Mol­e­c­u­lar Sci­ences, CR&D
E. I. DuPont de Nemours & Co
Wilm­ing­ton, DE

Abstract — In the past three decades, there has been a con­cert­ed effort in the chem­i­cal, agro­chem­i­cal, phar­ma­ceu­ti­cal, nutraceu­ti­cal, and petro­le­um indus­tries to design cost-advan­taged, inher­ent­ly safer, sus­tain­able, and envi­ron­men­tal­ly-friend­ly process­es. Catal­y­sis plays a cru­cial role in improv­ing process effi­cien­cies and process inten­si­fi­ca­tion lead­ing to increased atom uti­liza­tion, reduced by-prod­uct for­ma­tion, cheap­er process, and low­er cap­i­tal invest­ment. Also, there is an increas­ing inter­est in using renew­ably-sourced feed­stocks for the pro­duc­tion of fuels, chem­i­cals, and advanced mate­ri­als due to fluc­tu­a­tions in petro­le­um prices, lim­it­ed avail­abil­i­ty of petro­le­um resources, and increas­ing con­sumer con­scious­ness about sus­tain­able process­es.
Although catal­y­sis is a major tour-de-force in dri­ving this effi­ca­cious and green chem­istry rev­o­lu­tion, the role of reac­tion engi­neer­ing, reac­tor design, process devel­op­ment, and opti­mum oper­at­ing con­di­tions can­not be under­es­ti­mat­ed. Some of the fun­da­men­tal con­cepts of catal­y­sis will be dis­cussed and linked to chem­i­cal process­es of indus­tri­al rel­e­vance. Specif­i­cal­ly, the role of sci­ence and engi­neer­ing in indus­tri­al catal­y­sis will be illus­trat­ed with par­tic­u­lar empha­sis on cat­a­lyst eval­u­a­tion, process opti­miza­tion, cat­a­lyst deac­ti­va­tion, and reac­tor design asso­ci­at­ed with indus­tri­al process­es. Case stud­ies will include hydro­gena­tion reac­tions using sup­port­ed base met­al and pre­cious met­al cat­a­lysts and sol­id acid cat­alyzed reac­tions, includ­ing the hydro­gena­tion of hexa­flu­o­roace­tone and cat­mint oil, and dehy­dra­tion of xylose.
Biog­ra­phy — Dr. Sourav K. Sen­gup­ta is a Research Fel­low in the Mol­e­c­u­lar Sci­ences Divi­sion (Cen­tral Research & Devel­op­ment Depart­ment) of E. I. DuPont de Nemours & Co. He received his PhD degree in Chem­i­cal Engi­neer­ing from the Uni­ver­si­ty of Delaware in 1991. Imme­di­ate­ly after com­plet­ing his PhD, Dr. Sen­gup­ta joined the DuPont Com­pa­ny and was placed on loan to Cono­co where he devel­oped nov­el path­ways for the oxida­tive desul­fu­r­iza­tion of gaso­line and qual­i­fied new hydrodesul­fu­r­iza­tion and FCC cat­a­lysts. Short­ly after­wards, he was trans­ferred to the Cor­po­rate Catal­y­sis Cen­ter (CR&D). At CR&D, he worked on sol­id acid, sol­id base, and hydro­gena­tion catal­y­sis pro­grams and made impor­tant con­tri­bu­tions to a num­ber of Strate­gic Busi­ness Unit (SBUs).
Dr. Sen­gup­ta spent sev­er­al years at DuPont’s Nylon busi­ness unit, where he worked on a num­ber of com­mer­cial process­es and research pro­grams, includ­ing low-pres­sure and high-pres­sure ADN hydro­gena­tion, hydro­gen cyanide syn­the­sis by Andrus­sow and induc­tion-heat­ing process­es, and nitrous oxide destruc­tion cat­a­lyst tech­nol­o­gy.
When DuPont sold their Nylon, poly­ester, and Lycra busi­ness­es to Koch Indus­tries, Dr. Sen­gup­ta joined Invista, a whol­ly-owned sub­sidiary of Koch Indus­tries, where his work involved inves­ti­gat­ing the tech­ni­cal and eco­nom­ic fea­si­bil­i­ty of capro­lac­tam com­mer­cial­iza­tion.
After a short stint at Invista, Dr. Sen­gup­ta came back to DuPont, and joined their Chem­i­cal Solu­tions Enter­prise (DCSE) as a man­u­fac­tur­ing tech­ni­cal chemist at Cham­bers Works in New Jer­sey. His respon­si­bil­i­ty cov­ered 42 dif­fer­ent spe­cial­ty chem­i­cals. There he worked with a team of experts to design, devel­op, and com­mer­cial­ize a nov­el hydro­gena­tion process for the pro­duc­tion of hexa­flu­o­roiso­propanol (HFIP) and hexa­flu­o­roace­tone (HFA) recov­ery process. He was also involved in the com­mer­cial­iza­tion of a num­ber of Cap­stone prod­ucts. In 2009, he start­ed up a Process Devel­op­ment Cen­ter for DCSE at the Exper­i­men­tal Sta­tion. In 2011, he moved back to CR&D and has been work­ing on a num­ber of R&D pro­grams on using renew­able feed­stock to man­u­fac­ture chem­i­cals and mate­ri­als and new cat­a­lyst devel­op­ment.
Dr. Sengupta’s exper­tise is in the area of catal­y­sis, reac­tion engi­neer­ing and reac­tor analy­sis, and process devel­op­ment. He has over 65 US patents, pub­li­ca­tions, and pre­sen­ta­tions to his cred­it.

The Design of New Catalysts for Biomass Conversion with Atomic Layer Deposition

Meeting Program — April 2015

George Huber
Depart­ment of Chem­i­cal and Bio­log­i­cal Engi­neer­ing
Uni­ver­si­ty of Wis­con­sin, Madi­son, WI

The objec­tive of the Huber research group is to devel­op new cat­alyt­ic process­es and cat­alyt­ic mate­ri­als for the pro­duc­tion of renew­able fuels and chem­i­cals from bio­mass, solar ener­gy, and nat­ur­al gas resources. We use a wide range of mod­ern chem­i­cal engi­neer­ing tools to design and opti­mize these clean tech­nolo­gies includ­ing: het­ero­ge­neous catal­y­sis, kinet­ic mod­el­ing, reac­tion engi­neer­ing, spec­troscopy, ana­lyt­i­cal chem­istry, nan­otech­nol­o­gy, cat­a­lyst syn­the­sis, con­cep­tu­al process design, and the­o­ret­i­cal chem­istry. In this pre­sen­ta­tion we will first dis­cuss the hydrodeoxy­gena­tion of bio­mass into dif­fer­ent fuels and chem­i­cals. In addi­tion we can use HDO to eas­i­ly pro­duce new class­es mol­e­cules that are not cur­rent­ly pro­duced from petro­le­um feed­stocks. Hydrodeoxy­gena­tion (HDO) is a plat­form tech­nol­o­gy used to con­vert liq­uid bio­mass feed­stocks (includ­ing aque­ous car­bo­hy­drates, pyrol­y­sis oils, and aque­ous enzy­mat­ic prod­ucts) into alka­nes, alco­hols and poly­ols. In this process the bio­mass feed reacts with hydro­gen to pro­duce water and a deoxy­genat­ed prod­uct using a bifunc­tion­al cat­a­lyst that con­tains both met­al and acid sites. The chal­lenge with HDO is to selec­tive­ly pro­duce tar­get­ed prod­ucts that can be used as fuel blend­stocks or chem­i­cals and to decrease the hydro­gen con­sump­tion. We will dis­cuss how dif­fer­ent bio­mass based feed­stocks can be con­vert­ed into fuels or chem­i­cals by HDO. We will out­line the fun­da­men­tal cat­alyt­ic chem­istry and the sci­en­tif­ic chal­lenges. We will then dis­cuss how ALD can be used to design improved cat­alyt­ic mate­ri­als.

Atom­ic lay­er depo­si­tion (ALD) has emerged as a tool for the atom­i­cal­ly pre­cise design and syn­the­sis of cat­alyt­ic mate­ri­als. We dis­cuss exam­ples where the atom­ic pre­ci­sion has been used to elu­ci­date reac­tion mech­a­nisms and cat­a­lyst struc­ture-prop­er­ty rela­tion­ships by cre­at­ing mate­ri­als with a con­trolled dis­tri­b­u­tion of size, com­po­si­tion, and active site. We high­light ways ALD has been uti­lized to design cat­a­lysts with improved activ­i­ty, selec­tiv­i­ty, and sta­bil­i­ty under a vari­ety of con­di­tions (e.g., high tem­per­a­ture, gas- and liq­uid-phase, and cor­ro­sive envi­ron­ments). In addi­tion, due to the flex­i­bil­i­ty and con­trol of struc­ture and com­po­si­tion, ALD can cre­ate myr­i­ad cat­alyt­ic struc­tures (e.g., high sur­face area oxides, met­al nanopar­ti­cles, bimetal­lic nanopar­ti­cles, bifunc­tion­al cat­a­lysts, con­trolled micro-envi­ron­ments, etc.) that con­se­quent­ly pos­sess applic­a­bil­i­ty for a wide-rang­ing num­ber of chem­i­cal reac­tions (e.g., CO2 con­ver­sion, elec­tro­catal­y­sis, pho­to­cat­alyt­ic and ther­mal water split­ting, methane con­ver­sion, ethane and propane dehy­dro­gena­tion, and bio­mass con­ver­sion). Final­ly, the out­look for ALD-derived cat­alyt­ic mate­ri­als is dis­cussed with empha­sis on the pend­ing chal­lenges as well as areas of sig­nif­i­cant poten­tial for build­ing sci­en­tif­ic insight and achiev­ing prac­ti­cal impacts.

George Huber
George W. Huber is a Pro­fes­sor of Chem­i­cal Engi­neer­ing at Uni­ver­si­ty of Wis­con­sin-Madi­son. His research focus is on devel­op­ing new cat­alyt­ic process­es for the pro­duc­tion of renew­able liq­uid fuels and chem­i­cals.

George is one of the most high­ly cit­ed young schol­ars in the chem­i­cal sci­ences being cit­ed over 3,200 times in 2014 and over 14,000 times in his career. He has authored over 100 peer-reviewed pub­li­ca­tions includ­ing three pub­li­ca­tions in Sci­ence. Patents and tech­nolo­gies he has helped devel­op have been licensed by three dif­fer­ent com­pa­nies. He has received sev­er­al awards includ­ing the NSF CAREER award, the Drey­fus Teacher-Schol­ar award, fel­low of the Roy­al Soci­ety of Chem­istry, and the out­stand­ing young fac­ul­ty award (2010) by the col­lege of engi­neer­ing at UMass-Amherst. He has been named one of the top 100 peo­ple in bioen­er­gy by Bio­fu­els Digest for the past 3 years. He is co-founder of Anel­lotech a bio­chem­i­cal com­pa­ny focused on com­mer­cial­iz­ing, cat­alyt­ic fast pyrol­y­sis, a tech­nol­o­gy to pro­duce renew­able aro­mat­ics from bio­mass. George serves on the edi­to­r­i­al board of Ener­gy and Envi­ron­men­tal Sci­ence, Chem­CatChem, and The Cat­a­lyst Review. In June 2007, he chaired a NSF and DOE fund­ed work­shop enti­tled: Break­ing the Chem­i­cal and Engi­neer­ing Bar­ri­ers to Lig­no­cel­lu­losic Bio­fu­els (www​.ecs​.umass​.edu/​b​i​o​f​u​els).

George did a post-doc­tor­al stay with Aveli­no Cor­ma at the Tech­ni­cal Chem­i­cal Insti­tute at the Poly­tech­ni­cal Uni­ver­si­ty of Valen­cia, Spain (UPV-CSIC) where he stud­ied bio-fuels pro­duc­tion using petro­le­um refin­ing tech­nolo­gies. He obtained his Ph.D. in Chem­i­cal Engi­neer­ing from Uni­ver­si­ty of Wis­con­sin-Madi­son (2005). He obtained his B.S. (1999) and M.S.(2000) degrees in Chem­i­cal Engi­neer­ing from Brigham Young Uni­ver­si­ty.

DFT Investigation of Hydrogenation and Dehydrogenation Reactions on Binary Metal Alloys: Effect of Surface Ensembles and Composition

Meeting Program — March 2015

Fuat E Celik
Depart­ment of Chem­i­cal and Bio­mol­e­c­u­lar Engi­neer­ing
Rut­gers, The State Uni­ver­si­ty of New Jer­sey

Fuat Celik
In sup­port­ed met­al cat­a­lysts, the trade­off between activ­i­ty and selec­tiv­i­ty presents an impor­tant chal­lenge for cat­a­lyst design. By allow­ing two dis­sim­i­lar met­als, we can attempt to tune the selec­tiv­i­ty of the cat­a­lyst by enhanc­ing bond-for­ma­tion and des­orp­tion rates through the addi­tion of a less-reac­tive ele­ment, while main­tain high bond dis­so­ci­a­tion activ­i­ty from the more active met­al. The result­ing cat­a­lyst prop­er­ties depend strong­ly on the cat­a­lyst com­po­si­tion and ratio of the two met­als (elec­tron­ic effect), but may also depend on the local struc­ture of sur­face ensem­bles of the alloy com­po­nents (geo­met­ric effect). In this talk we will explore two exam­ples of bina­ry alloys where sur­face com­po­si­tion and geom­e­try play an impor­tant role in deter­min­ing the selec­tiv­i­ty of the cat­a­lyst through den­si­ty func­tion­al the­o­ry (DFT).

In the first exam­ple, we have exam­ined the effect of plat­inum tin alloy struc­ture and com­po­si­tion on the kinet­ics and ther­mo­dy­nam­ics of dehy­dro­gena­tion and coke for­ma­tion path­ways dur­ing light alka­ne dehy­dro­gena­tion. Light alka­ne dehy­dro­gena­tion to olefins can add sig­nif­i­cant val­ue to hydro­car­bon process­es that gen­er­ate ethane and propane by con­vert­ing low val­ue com­mod­i­ty fuels to high-val­ue chem­i­cal and poly­mer pre­cur­sors. Sup­port­ed Pt cat­a­lysts are known to be active but show sig­nif­i­cant coke for­ma­tion and deac­ti­va­tion, which can be alle­vi­at­ed by alloy­ing with Sn and oth­er main group ele­ments. We aim to under­stand how the struc­ture and com­po­si­tion of these alloys affect their abil­i­ty to sup­press coke for­ma­tion. We inves­ti­gate the poten­tial ener­gy sur­faces from ethane along the desired path­way to ethene, and along the unde­sired path­ways towards sur­face carbon/coke. The effect of Pt/Sn ratio and sur­face geom­e­try is inves­ti­gat­ed. As com­pared to pure Pt, bond scis­sion is more dif­fi­cult on the alloys and des­orp­tion is more facile, and both effects are enhanced as three-fold hol­low sites con­sist­ing of only Pt atoms are elim­i­nat­ed.

In the sec­ond exam­ple, we eval­u­ate Au/Ni near-sur­face alloys as poten­tial oxy­gen reduc­tion cat­a­lysts for the direct syn­the­sis of hydro­gen per­ox­ide from O2 and H2, there­by avoid­ing the cur­rent anthraquinone process. While Au may have high­er O-H bond for­ma­tion activ­i­ty, it is a poor O2-dis­so­ci­a­tion cat­a­lyst, and like­wise Ni is very effec­tive at O2-dis­so­ci­a­tion but not oxy­gen hydro­gena­tion. Alloy­ing Au with Ni(111) low­ers H2 dis­so­ci­a­tion bar­ri­er while keep­ing the O2 dis­so­ci­a­tion bar­ri­er large rel­a­tive to O2 hydro­gena­tion. Des­orp­tion of H2O2 is sim­i­lar­ly com­pet­i­tive with H2O2 dis­so­ci­a­tion on alloy sur­faces. How­ev­er, the selec­tiv­i­ty for the OOH rad­i­cal remains a chal­lenge, with bar­ri­er­less O-O bond dis­so­ci­a­tion and large (1.3 eV) hydro­gena­tion bar­ri­ers. We fur­ther inves­ti­gate how the Au/Ni sur­face may rearrange itself to regen­er­ate three-fold hol­lows of Ni atoms in the pres­ence of strong­ly adsorb­ing sur­face species.

Methane Conversion to Methanol on Copper Containing Small Pore Zeolites

Meeting Program — February 2015

Bahar Ipek
Depart­ment of Chem­i­cal and Bio­mol­e­c­u­lar Engi­neer­ing
Uni­ver­si­ty of Delaware

Bahar Ipek
Methan­otroph­ic bac­te­ria con­tain­ing par­tic­u­lar methane monooxy­ge­nase (pMMO), a Cu-con­tain­ing enzyme, or sol­u­ble methane monooxy­ge­nase (sMMO), an iron-met­al­loen­zyme can oxi­dize methane to methanol selec­tive­ly at ambi­ent con­di­tions 1. The zeo­lite Cu-ZSM-5 was report­ed to acti­vate the methane C-H bond—with a homolyt­ic bond dis­so­ci­a­tion ener­gy of 104 kcal/mol— at tem­per­a­tures as low as 120 °C 2 after pre­treat­ment in O2 3. The reac­tive cop­per species are believed to con­tain extra-lat­tice oxy­gen, and in the case of Cu-ZSM-5, to be a mono-μ-oxo-dicop­per com­plex ([Cu—O—Cu]2+) 4. Although a cor­re­la­tion was found between the con­cen­tra­tion of mono-μ-oxo-dicop­per species and the amount of methanol pro­duced by Cu-ZSM-5 5, no such cor­re­la­tion was found for oth­er zeo­lites that pro­duce methanol such as Cu-mor­den­ite and Cu-fer­rierite 2. We have recent­ly showed methanol pro­duc­tion on cop­per (II) exchanged small pore zeo­lites includ­ing SSZ-13 (CHA), SSZ-16 (AFX) and SSZ-39 (AEI) with yields as high as 39 μmol CH3OH/g and CH3OH/Cu ratios up to 0.09 (the largest report­ed to date).6 Here, cop­per species in these small pore zeo­lites were inves­ti­gat­ed with UV–vis and Raman spec­troscopy after O2-treat­ment at a tem­per­a­ture of 450 °C. No evi­dence of mono-μ-oxo-dicop­per species was found in the spec­tra of Cu-SSZ-13,Cu-SSZ-16 and Cu-SSZ-39 6, how­ev­er Cu—Oextralattice vibra­tions at 574 cm-1 were detect­ed in Raman spec­tra of Cu-SSZ-13 and Cu-SSZ-39 zeo­lites which is indica­tive of a dif­fer­ent Cux­Oy active species respon­si­ble for methanol pro­duc­tion in small pore zeo­lites.

1. Han­son, R. S.; Han­son, T. E., Methan­otroph­ic Bac­te­ria. Micro­bi­o­log­i­cal Reviews
1996, 60, 439–471.
2. Smeets, P. J.; Groothaert, M. H.; Schoonhey­dt, R. A., Cu based zeo­lites: A UV–vis
study of the active site in the selec­tive methane oxi­da­tion at low tem­per­a­tures.
Catal. Today 2005, 110 (3–4), 303–309.
3. Groothaert, M. H.; Smeets, P. J.; Sels, B. F.; Jacobs, P. A.; Schoonhey­dt, R. A.,
Selec­tive Oxi­da­tion of Methane by the Bis(mu-oxo)dicopper Core Sta­bi­lized on
ZSM-5 and Mor­den­ite Zeo­lites. Jour­nal of Amer­i­can Chem­i­cal Soci­ety 2005, 127,
4. Woertink, J. S.; Smeets, P. J.; Groothaert, M. H.; Vance, M. A.; Sels, B. F.;
Schoonhey­dt, R. A.; Solomon, E. I., A [Cu2O]2+ core in Cu-ZSM-5, the active site in
the oxi­da­tion of methane to methanol. Pro­ceed­ings of the Nation­al Acad­e­my of
Sci­ences of the Unit­ed States of Amer­i­ca 2009, 106 (45), 18908–13.
5. Bez­nis, N. V.; Weck­huy­sen, B. M.; Bit­ter, J. H., Cu-ZSM-5 Zeo­lites for the For­ma­tion
of Methanol from Methane and Oxy­gen: Prob­ing the Active Sites and Spec­ta­tor
Species. Catal. Lett. 2010, 138 (1–2), 14–22.
6. Wulfers, M. J.; Teke­tel, S.; Ipek, B.; Lobo, R. F., Con­ver­sion of Methane to Methanol
on Cop­per Con­tain­ing Small Pore Zeo­lites and Zeo­types. Chem Com­mun 2015, xx,

Bridging Heterogeneous Catalysis and Electro-catalysis: Catalytic Reactions Involving Oxygen

Meeting Program — February 2015

Dr. Umit S. Ozkan
Depart­ment of Chem­i­cal and Bio­mol­e­c­u­lar Engi­neer­ing
The Ohio State Uni­ver­si­ty

Umit Ozkan
Cat­alyt­ic reac­tions that involve oxy­gen can be found in a large num­ber of process­es, includ­ing those in ener­gy-relat­ed appli­ca­tions, in emis­sion con­trol and in process­es impor­tant for the chem­i­cal indus­try. Whether the cat­alyt­ic reac­tion is an oxy­gen inser­tion step as in a selec­tive oxi­da­tion reac­tion, or an oxy­gen removal step as in a hydrodeoxy­gena­tion reac­tion, oxy­gen has proven to be a very chal­leng­ing com­po­nent, often deter­min­ing the selec­tiv­i­ty of the reac­tion. Some exam­ples from our lab­o­ra­to­ries that bridge catal­y­sis and elec­tro-catal­y­sis will be dis­cussed, rang­ing from oxida­tive dehy­dro­gena­tion of alka­nes to oxy­gen reduc­tion reac­tion in fuel cells.

Challenges and Advances in Catalytic Fast Pyrolysis of Biomass using Zeolites

Meeting Program — January 2015

Dr. Julia Val­la
Chem­i­cal and Bio­mol­e­c­u­lar Engi­neer­ing Depart­ment
Uni­ver­si­ty of Con­necti­cut, Storrs, CT

Ther­mo­chem­i­cal con­ver­sion of bio­mass to ener­gy, fuels and chem­i­cals is an attrac­tive tech­nol­o­gy for the tran­si­tion from fos­sil resources to a renew­able-based econ­o­my. Cat­alyt­ic Fast Pyrol­y­sis (CFP) of bio­mass is a par­tic­u­lar­ly inter­est­ing tech­nol­o­gy for bio­mass con­ver­sion con­sid­er­ing the already exten­sive infra­struc­ture for hydro­car­bons pro­duc­tion. How­ev­er, many chal­lenges remain unsolved before the deploy­ment of the bio­mass CFP can be real­ized, includ­ing: a) char and coke for­ma­tion, which caus­es rapid cat­a­lyst deac­ti­va­tion; and b) high oxy­gen con­tent in the bio-oil, which makes it incom­pat­i­ble with today’s hydro­car­bon fuels. With respect to the first chal­lenge, it is imper­a­tive to first under­stand the ori­gin and the for­ma­tion of char and coke dur­ing CFP. Con­sid­er­ing the sec­ond chal­lenge, it is impor­tant to under­stand which cat­a­lyst prop­er­ties can enhance the deoxy­gena­tion reac­tions and increase the bio-oil selec­tiv­i­ty to hydro­car­bons. ZSM-5 zeo­lites have been rec­og­nized as one of the most promis­ing zeo­lites for CFP due to their shape selec­tiv­i­ty and their deoxy­gena­tion abil­i­ty. How­ev­er, their micro­p­ore struc­ture can lim­it the acces­si­bil­i­ty of heavy com­pounds to the active sites of their frame­work. Mod­i­fy­ing the zeo­lite pore archi­tec­ture to cre­ate hier­ar­chi­cal struc­tures could pro­vide a solu­tion to this chal­lenge. Fur­ther­more, the CFP process design itself (in situ or ex situ) can alter the prod­uct yield and selec­tiv­i­ty and, thus, the bio-oil qual­i­ty. Dur­ing this pre­sen­ta­tion we will dis­cuss how the zeo­lite prop­er­ties and loca­tion with­in the CFP process (in situ or ex situ) can affect the coke/char for­ma­tion and the deoxy­gena­tion reac­tions for enhanced bio-oil qual­i­ty.
Julia Valla
Iou­lia (Julia) Val­la is an Assis­tant Pro­fes­sor in the Chem­i­cal & Bio­mol­e­c­u­lar Engi­neer­ing Depart­ment at the Uni­ver­si­ty of Con­necti­cut. She received her PhD in the field of the devel­op­ment of new zeo­lites for the decom­po­si­tion of sul­fur com­pounds in naph­tha and the pro­duc­tion of envi­ron­men­tal gaso­line from the Aris­to­tle Uni­ver­si­ty of Thes­sa­loni­ki in Greece. She has served in a lead­er­ship role with Rive Tech­nol­o­gy, Inc. on the com­mer­cial­iza­tion of a nov­el zeo­lite with ordered meso­porous struc­ture for refin­ery appli­ca­tions. Dr. Valla’s research focus­es on the mod­i­fi­ca­tion of zeo­lites struc­ture and their appli­ca­tion in catal­y­sis, adsorp­tion and ener­gy. She is the author/­co-author of 9 papers in peer-reviewed jour­nals, 1 book chap­ter and 2 patents. Dr. Val­la is the recip­i­ent of the Euro­pean Award “RUCADI, Recov­ery and Uti­liza­tion of Car­bon Diox­ide” for her study on the role of CO2 on the reform­ing of nat­ur­al gas for the pro­duc­tion of methanol. At the Uni­ver­si­ty of Con­necti­cut, Dr. Val­la received an award spon­sored by the Nation­al Sci­ence Foun­da­tion for the study “Turn­ing Tars into Ener­gy: Zeo­lites with Hier­ar­chi­cal Pore Struc­ture for the Cat­alyt­ic Removal of Tars”. The study is focused on a nov­el appli­ca­tion of hier­ar­chi­cal­ly struc­tured meso­porous bifunc­tion­al cat­a­lysts for the ther­mo­chem­i­cal upgrad­ing of unde­sir­able tars from bio­mass pyrol­y­sis or gasi­fi­ca­tion to valu­able hydro­car­bons.

Challenges and Solutions in Developing Zeolite Supported Transition Metal Catalysts for Lean-Burn NOx Emission Control

Meeting Program — September 2014

Hai-Ying Chen
Emis­sion Con­trol Tech­nolo­gies
John­son Matthey Inc.
Wayne, PA

Abstract — Reduc­tion of NOx emis­sions from lean-burn engine exhaust has been a main top­ic of envi­ron­men­tal catal­y­sis in the past 20 years. The chal­lenge is the selec­tive con­ver­sion of a low con­cen­tra­tion of NOx (~100 ppm) in the pres­ence of large excess of O2 (~10%). Although zeo­lite sup­port­ed tran­si­tion met­al cat­a­lysts were iden­ti­fied in ear­ly 1990s as promis­ing cat­a­lysts, such a tech­nol­o­gy was not imple­ment­ed till recent­ly.

Ear­ly stud­ies main­ly focused on the devel­op­ment of zeo­lite sup­port­ed tran­si­tion met­al, pri­mar­i­ly Cu and Fe, cat­a­lysts for the selec­tive cat­alyt­ic reduc­tion of NOx with hydro­car­bons (HC-SCR). Even though the HC-SCR tech­nol­o­gy has been con­sid­ered as the “holy grail” of auto­mo­tive catal­y­sis, tech­ni­cal chal­lenges on the activ­i­ty, selec­tive and dura­bil­i­ty of the cat­a­lysts were rec­og­nized to be dif­fi­cult to over­come for the tech­nol­o­gy to be imple­ment­ed into real world appli­ca­tions. How­ev­er, the vast amount of research work, espe­cial­ly the fun­da­men­tal stud­ies on the reac­tion and the cat­a­lyst deac­ti­va­tion mech­a­nisms, demon­strat­ed that the activ­i­ty and selec­tiv­i­ty of this type of cat­a­lysts can be dras­ti­cal­ly improved if an alter­na­tive reduc­tant, NH3, is avail­able in the feed.

Exten­sive inves­ti­ga­tions on the selec­tive cat­alyt­ic reduc­tion of NOx with NH3 (NH3-SCR) began in the mid­dle 2000s aimed to enable diesel pow­ered vehi­cles to meet the US EPA 2007/2010 emis­sion reg­u­la­tions. Both Cu and Fe cat­a­lysts were con­sid­ered. Zeo­lite sup­port­ed Cu SCR cat­a­lysts are more active at low tem­per­a­ture, thus more attrac­tive for appli­ca­tions with low exhaust tem­per­a­ture. The con­ven­tion­al medi­um-pore zeo­lite (10-ring, such as ZSM-5) or large-pore zeo­lite (12-ring, such as beta) sup­port­ed Cu cat­a­lysts, how­ev­er, can­not meet the long-term dura­bil­i­ty require­ments. To over­come this major tech­ni­cal hur­dle, small-pore zeo­lite (8-ring) sup­port­ed Cu cat­a­lysts were invent­ed. On the oth­er hand, zeo­lite sup­port­ed Fe SCR cat­a­lysts are more selec­tive in uti­liz­ing NH3 for NOx reduc­tion at high tem­per­a­tures but show a strong depen­dence on the NO to NO2 ratio in the feed gas at low tem­per­a­tures. Sys­tem approach­es were devel­oped to enhance the low tem­per­a­ture SCR activ­i­ty of the Fe SCR cat­a­lysts. As such, both Cu and Fe SCR cat­a­lysts were suc­cess­ful­ly com­mer­cial­ized and applied on lean-burn diesel vehi­cles meet­ing the strin­gent US EPA 2010 emis­sion stan­dards.

Hai-Ying ChenBiog­ra­phy — Dr. Hai-Ying Chen is a Sci­en­tif­ic and Prod­uct Devel­op­ment Man­ag­er at John­son Matthey, where he leads a team of sci­en­tists to devel­op advanced emis­sion con­trol cat­a­lysts and tech­nolo­gies for both gaso­line engine and diesel engine pow­ered vehi­cles to meet the gov­ern­ment emis­sion reg­u­la­tions.

Dr. Chen received his Ph.D. in Chem­istry from Fudan Uni­ver­si­ty, Chi­na. He has pub­lished more than 50 tech­ni­cal papers in peer-reviewed jour­nals and holds 14 US/international patents. He received the Top Cit­ed Arti­cle Award by Catal­y­sis Today for arti­cles pub­lished in 1998, and was a recip­i­ent of the Amer­i­can Chem­i­cal Soci­ety Award for Team Inno­va­tion in 2009. He was named as the 2014 Her­man Pines Award in Catal­y­sis by the Chica­go Catal­y­sis Club and the 2014 Catal­y­sis Club of Philadel­phia Award by the Catal­y­sis Club of Philadel­phia.