2009 Spring Symposium

 
Suljo Lin­ic
Depart­ment of Chem­i­cal Engi­neer­ing
Uni­ver­si­ty of Michi­gan
Ann Arbor, MI

Abstract — The cen­tral objec­tive of our research effort is to employ com­bined experimental/theoretical approach­es to devel­op pre­dic­tive the­o­ries of het­ero­ge­neous catal­y­sis and to apply these the­o­ries to for­mu­late ener­gy-effi­cient, selec­tive, and sta­ble cat­a­lysts. We are moti­vat­ed by a real­iza­tion that recent sci­en­tif­ic advance­ments, main­ly in the area of mol­e­c­u­lar sci­ence, have poten­tial to bring a rev­o­lu­tion­ary trans­for­ma­tion to the field of dis­cov­ery in het­ero­ge­neous cat­a­lysts.

I will present our recent work where we explored poten­tial uti­liza­tion of high­ly uni­form metal­lic nano-struc­tured mate­ri­als as selec­tive het­ero­ge­neous cat­a­lysts. The advan­tage of these mate­ri­als com­pared to con­ven­tion­al cat­alyt­ic mate­ri­als is that their struc­ture can be con­trolled with almost atom­ic pre­ci­sion, and that it is pos­si­ble to syn­the­size high­ly homo­ge­neous struc­tures. We demon­strat­ed some of these advan­tages recent­ly when we showed that well-defined, tai­lored Ag nano-struc­tures are much more selec­tive in het­ero­ge­neous epox­i­da­tion of eth­yl­ene to form eth­yl­ene oxide (EO) (Eth­yl­ene + ½O₂ → EO) than con­ven­tion­al indus­tri­al cat­a­lysts.

We showed using quan­tum chem­i­cal Den­si­ty Func­tion­al The­o­ry (DFT) cal­cu­la­tions, where we stud­ied crit­i­cal ele­men­tary chem­i­cal steps that gov­ern the selec­tiv­i­ty to EO in the process, that the Ag(100) sur­face should be inher­ent­ly more selec­tive than the Ag(111) sur­face. We note that cat­alyt­ic par­ti­cles, syn­the­sized using con­ven­tion­al syn­the­sis pro­ce­dure and cur­rent­ly used in com­mer­cial eth­yl­ene epox­i­da­tion process, are dom­i­nat­ed by the (111) sur­face. To syn­the­size Ag nano-struc­tures which are dom­i­nat­ed with the Ag(100) faces, we employed a syn­the­sis pro­ce­dure which uses organ­ic sta­bi­liz­er mol­e­cules to direct the growth of the nano-struc­ture in a par­tic­u­lar direc­tion and to con­trol the sur­face facets that ter­mi­nate the nano-struc­ture. This syn­thet­ics strat­e­gy allowed us to syn­the­size well-defined and high­ly uni­form Ag nano-wires and nano-cubes which are dom­i­nat­ed by the (100) facet. Sub­se­quent exper­i­ments showed that Ag nano-wires and nano-cube cat­a­lysts can achieve selec­tiv­i­ty to EO, which is, at dif­fer­en­tial con­ver­sion, by ~ 40 % high­er than for con­ven­tion­al Ag cat­a­lysts.

We have also recent­ly start­ed explor­ing these metal­lic nano-struc­tures as pos­si­ble plat­forms for chem­i­cal char­ac­ter­i­za­tion. The fea­tures of these nano-struc­tures that are par­tic­u­lar­ly appeal­ing are: (i) the nanos­truc­tures are well defined on atom­ic lev­el, and their sur­face to vol­ume ratio is fair­ly high, which makes these struc­tures inher­ent­ly bet­ter suit­ed for the stud­ies of sur­face chem­i­cal process­es com­pared to tra­di­tion­al sin­gle crys­tal mod­el sys­tems, which are while very well defined, char­ac­ter­ized by low sur­face to vol­ume ratio. (ii) we can syn­the­size the nanos­truc­tures with high degree of uni­for­mi­ty in size and shape, which rules out pos­si­ble effects due to diver­si­ty in size and shape, i.e. these, (iii) the nanos­truc­tures are effec­tive scat­ter­ers of elec­tro­mag­net­ic radi­a­tion which make them suit­able as plat­forms for a num­ber of chem­i­cal char­ac­ter­i­za­tion tech­niques includ­ing sur­face enhanced Raman (SERS) or IR spec­tro­scopies. We will demon­strate the util­i­ty of the nano-struc­tures for chem­i­cal char­ac­ter­i­za­tion by a way of an exam­ple, where we mon­i­tored in-situ eth­yl­ene epox­i­da­tion.

We will also show that the well-defined metal­lic nano-struc­tures exhib­it inter­est­ing prop­er­ties when exposed to UV and vis­i­ble light. We will show how these char­ac­ter­is­tics can be used to design nov­el pho­to-elec­tro-cat­alyt­ic mate­ri­als and process­es.

Speaker’s Biog­ra­phy — Suljo Linc came to the Unit­ed States from Bosnia under the aus­pices of a Soros Foun­da­tion Fel­low­ship, here he received a BS degree in Physics from West Chester Uni­ver­si­ty (1998) , and a Ph.D. in Chem­i­cal Engi­neer­ing under Pro­fes­sor Mark Barteau (2003) where he inves­ti­gat­ed the the­o­ret­i­cal and exper­i­men­tal aspects of alkene par­tial oxi­da­tion on sil­ver. He accept­ed a post­doc­tor­al posi­tion in Matthias Scheffler’s The­o­ry Group at the Fritz Haber Insti­tute of the Max Planck Soci­ety in Berlin, and in 2004 took a posi­tion in the Depart­ment of Chem­i­cal Engi­neer­ing at the Uni­ver­si­ty of Michi­gan. Suljo has received a num­ber of awards, includ­ing NSF Career Award in 2006, and Young Sci­en­tist Prize from the Coun­cil of the Inter­na­tion­al Asso­ci­a­tion of Catal­y­sis Soci­eties, Paris, France, July 2004. Suljo’s research inter­ests include fuel cells, chi­ral syn­the­sis, car­bon catal­y­sis, catal­y­sis at nano-scales, and the fun­da­men­tals of sur­face activ­i­ty and selec­tiv­i­ty.

2009 Spring Symposium

 
Michael Ward
New York Uni­ver­si­ty
Depart­ment of Chem­istry
New York, NY

Abstract — Guest-free guani­dini­um organomono­sul­fonates (GMS) and their inclu­sion com­pounds dis­play a vari­ety of lamel­lar crys­talline archi­tec­tures dis­tin­guished by dif­fer­ent “up-down” pro­jec­tions of the organomono­sul­fonate residues on either side of a two-dimen­sion­al (2D) hydro­gen-bond­ing net­work of com­ple­men­tary guani­dini­um ions (G) and sul­fonate moi­eties (S), the so-called GS sheet. The GS sheets in the inclu­sion com­pounds behave as “mol­e­c­u­lar jaws” in which organomono­sul­fonate groups pro­ject­ing from oppos­ing sheets clamp down on the guest mol­e­cules, form­ing ordered inter­dig­i­tat­ed arrays of the host organ­ic groups and guests. Guest-free and inclu­sion com­pounds dis­play a vari­ety of archi­tec­tures that reveal the struc­tur­al integri­ty of two-dimen­sion­al GS sheet and the unique abil­i­ty of these hosts to con­form to the steric demands of the organ­ic guests. Cer­tain GMS host-guest com­bi­na­tions prompt for­ma­tion of tubu­lar inclu­sion com­pounds in which the GS sheet curls into cylin­ders with reten­tion of the 2D GS net­work. The cylin­ders assem­ble into hexag­o­nal arrays through inter­dig­i­ta­tion of the organosul­fonate residues that project from their out­er sur­faces, crys­tal­liz­ing in high sym­me­try trig­o­nal or hexag­o­nal space groups. This unique exam­ple of net­work cur­va­ture and struc­tur­al iso­merism between lamel­lar and cylin­dri­cal struc­tures, with reten­tion of supramol­e­c­u­lar con­nec­tiv­i­ty, is rem­i­nis­cent of the phase behav­ior observed in sur­fac­tant microstruc­tures and block copoly­mers. The large num­ber of host-guest com­bi­na­tions explored here per­mits group­ing of the inclu­sion com­pound archi­tec­tures accord­ing to the shape of the guests and the rel­a­tive vol­umes of the organomono­sul­fonate groups, enabling more reli­able struc­ture pre­dic­tion for this class of com­pounds than for mol­e­c­u­lar crys­tals in gen­er­al. More recent results that demon­strate the inclu­sion of laser dyes with con­trolled states of aggre­ga­tion, the intro­duc­tion of mol­e­c­u­lar cap­sules, and unusu­al high sym­me­try struc­tures will be described.

Speaker’s Biog­ra­phy — Michael Ward earned his B.A in Chem­istry from William Pater­son Col­lege of New Jer­sey in 1977, and PhD in Chem­istry from Prince­ton Uni­ver­si­ty in 1981. He cur­rent­ly serves as the Sil­ver Pro­fes­sor and Chair, Depart­ment of Chem­istry, Direc­tor of Mol­e­c­u­lar Design Insti­tute and Direc­tor of Mate­ri­als Research Sci­ence and Engi­neer­ing Cen­ter at New York Uni­ver­si­ty, New York City, NY. He is also Edi­tor of Chem­istry of Mate­ri­als. His research inter­ests include syn­the­sis of mol­e­c­u­lar mate­ri­als and crys­tal engi­neer­ing, phys­i­cal and elec­tron­ic prop­er­ties of mol­e­c­u­lar solids, nucle­ation and growth of organ­ic and pro­tein crys­tals, scan­ning probe microscopy and inter­fa­cial phe­nom­e­na.

2009 Spring Symposium

 
Allen Bur­ton
Chevron Research
Rich­mond, Cal­i­for­nia

Abstract — The zeo­lite com­mu­ni­ty has recent­ly pre­pared a num­ber of new zeo­lite struc­tures byem­ploy­ing diqua­ter­nary ammo­ni­um mol­e­cules as struc­ture direct­ing agents (SDAs). Inpar­tic­u­lar, sev­er­al nov­el mul­ti­di­men­sion­al medi­um-pore zeo­lites have been dis­cov­ered that­pro­vide inter­est­ing com­par­isons with ZSM-5 in their struc­tur­al fea­tures and cat­alyt­ic behaviours.I will first dis­cuss how we have used diqua­ter­nary pyrro­li­dini­um mol­e­cules in flu­o­ride-medi­at­edgels to syn­the­size new zeo­lites like SSZ-74, SSZ-75, and SSZ-83. I will empha­size the struc­turalelu­ci­da­tion and prop­er­ties of SSZ-74, an excep­tion­al zeo­lite that pos­sess­es ordered tetra­he­dral­site vacan­cies. In the sec­ond part of the dis­cus­sion, I will describe how we have pre­pared­di­qua­ter­nary ammo­ni­um mol­e­cules from enam­ine pre­cur­sors. One of these SDA is used topre­pare the nov­el zeo­lite SSZ-82, and sev­er­al of the mol­e­cules are selec­tive for thea­lu­mi­nosil­i­cate and borosil­i­cate ver­sions of the SSZ-26/33 fam­i­ly, which has very few knownS­DA mol­e­cules

Speaker’s Biog­ra­phy — Allen Bur­ton received his BS in Chem­istry at the Uni­ver­si­ty of Mary­land at Col­lege Park, and his PhD in Chem­i­cal Engi­neer­ing from the Uni­ver­si­ty of Delaware under the guid­ance of Prof. Raul Lobo. It was here Allen dis­cov­ered his pas­sion for zeo­lite syn­the­sis, which he con­tin­ued under the post­doc­tor­al guid­ance of Prof Mark Davis at Cal­Tech. In 2001, Allen accept­ed a posi­tion in the research group at Chevron’s Research facil­i­ty in Rich­mond, CA. Despite his admit­ted inep­ti­tude in the game of golf, on week­ends he can some­times be found at the golf range (swear­ing at golf balls and throw­ing his irons).

2009 Spring Symposium

 
Michael Smith
Symyx

Abstract — Not avail­able.

2009 Spring Symposium

 
Stu­art Soled
Exxon Mobil Research and Engi­neer­ing Co.
Annan­dale, NJ 08801 USA

Abstract — With the resur­gent inter­est in Fis­ch­er-Trop­sch catal­y­sis, it is impor­tant to under­stand any cat­a­lyst changes that can occur dur­ing the syn­the­sis. In this pre­sen­ta­tion we report on three intrin­sic modes of deac­ti­va­tion that have been observed in stud­ies of exper­i­men­tal sup­port­ed Co cat­a­lysts. These include reversible sur­face oxi­da­tion, irre­versible mixed met­al oxide for­ma­tion, and cobalt par­ti­cle growth. Tech­niques to mon­i­tor these changes are pre­sent­ed as well as some hypothe­ses regard­ing the mech­a­nisms that are respon­si­ble for them.

Speaker’s Biog­ra­phy — Stu Soled received his Ph.D in chem­istry focused pri­mar­i­ly on x-ray crys­tal­log­ra­phy from Brown Uni­ver­si­ty in 1973. He then did 4 year of post-doc­tor­al work in sol­id state chem­istry both at Brown Uni­ver­si­ty and in France, focus­ing on the syn­the­sis and char­ac­ter­i­za­tion of nov­el oxide and sul­fide mate­ri­als. He has been at Exxon’s Cor­po­rate Research Labs for more than 28 years. His research inter­ests lie in the syn­the­sis, char­ac­ter­i­za­tion and eval­u­a­tion of nov­el cat­alyt­ic mate­ri­als. He has worked exten­sive­ly on Fis­ch­er-Trop­sch chem­istry, sol­id acid and met­al catal­y­sis, and hydrotreat­ing. He is the coau­thor of more than 70 pub­li­ca­tions and 80 U.S. patents. He is cred­it­ed with the dis­cov­ery of the Neb­u­la cat­a­lyst and has worked on a joint Exxon­Mo­bil-Albe­mar­le team to bring it to com­mer­cial real­i­ty. Neb­u­la has been pro­duc­ing low sul­fur diesel fuels in over a dozen refin­ery units world­wide. He is the recip­i­ent of the New York Catal­y­sis Soci­ety Excel­lence in Catal­y­sis Award, the North Amer­i­can Catal­y­sis Soci­ety Frank Cia­pet­ta Lec­ture­ship Award, the Amer­i­can Chem­i­cal Soci­ety North­east Divi­sion Indus­tri­al Inno­va­tion Award and the ACS Heroes in Chem­istry Award.

2009 Spring Symposium

 
Robert Schlögl
Fritz-Haber-Insti­tut der Max-Planck-Gesellschaft
Berlin, Ger­many

Abstract — The acti­va­tion of dioxy­gen into a selec­tive oxi­diz­ing species and the require­ment of acti­vat­ing C-H bonds lead to con­flict­ing struc­tures of active sites. Mate­r­i­al solu­tion of met­als and oxide sys­tems will be dis­cussed for the increas­ing­ly demand­ing cas­es of oxi­da­tion of methanol, eth­yl­ene and propane.

Speaker’s Biog­ra­phy — Robert Schlögl stud­ied chem­istry and com­plet­ed his PhD on graphite inter­ca­la­tion com­pounds at the Lud­wig Max­i­m­il­ians Uni­ver­si­ty in Munich (1982). After post­doc­tor­al stays at Cam­bridge and Basle he car­ried out his habil­i­ta­tion under the super­vi­sion of Pro­fes­sor Ertl at Fritz Haber Insti­tute in Berlin (1989). Lat­er he accept­ed the call for a Full Pro­fes­sor­ship of Inor­gan­ic Chem­istry at Frank­furt Uni­ver­si­ty. In 1994 he was appoint­ed his cur­rent posi­tion as Direc­tor at the Fritz Haber Insti­tute of the Max Planck Soci­ety in Berlin. His research activ­i­ties range from inter­fa­cial reac­tions of inor­gan­ic solids, het­ero­ge­neous catal­y­sis, spec­troscopy of sur­faces dur­ing chem­i­cal reac­tions, sol­id state reac­tions, acid-base chem­istry on sur­faces, car­bon chem­istry, chem­istry of oxide sys­tems to clus­ter chem­istry. Spe­cif­ic focus is on the inves­ti­ga­tion of het­ero­ge­neous cat­a­lysts based upon inor­gan­ic solids with the aim to bridge exper­i­men­tal­ly the gap between sur­face sci­ence and chem­i­cal engi­neer­ing in the field of oxi­da­tion catal­y­sis. He is author of about 500 pub­li­ca­tions and reg­is­tered inven­tor of more than 20 patent fam­i­lies. He is a Fel­low of the Roy­al Soci­ety of Chem­istry and mem­ber of numer­ous inter­na­tion­al orga­ni­za­tions. His research activ­i­ties have been rec­og­nized with sev­er­al inter­na­tion­al awards.

2008 Spring Symposium

 
Dion G. Vla­chos
Depart­ment of Chem­i­cal Engi­neer­ing
Cen­ter for Cat­alyt­ic Sci­ence and Tech­nol­o­gy (CCST)
Uni­ver­si­ty of Delaware
Newark, DE 19716–3110

Abstract — Future portable and dis­trib­uted ener­gy pro­duc­tion will hap­pen at much small­er­scales than the tra­di­tion­al econ­o­my of scales encoun­tered in oil and petro­chem­i­calin­dus­try. Reac­tors have to be much more com­pact and effi­cient and cat­a­lysts more active­and selec­tive. In this talk, three process­es of small­er scale hydro­gen pro­duc­tion will bep­re­sent­ed. The first is ammo­nia decom­po­si­tion on Ru.

Ammo­nia has one of the largest gravi­met­ric hydro­gen stor­age capac­i­ties and is an excel­lent COx-free fuel. We willd­is­cuss the chem­istry on Ru, the effect of par­ti­cle size and shape on activ­i­ty, and meth­od­sto find opti­mal cat­a­lysts. The oth­er process­es are par­tial oxi­da­tion and steam reform­ing ofmethane on Rh, a pro­to­type exam­ple of hydro­car­bon or bio­mass to syn­gas con­ver­sion­with inher­ent­ly more com­plex chem­istry. Steam reform­ing of methane to syn­gas has been­tra­di­tion­al­ly thought to be very slow and unsuit­able for onboard appli­ca­tion. We showthat all these process­es can run at sub­mil­lisec­ond con­tact times. The debate about directand indi­rect path­ways of par­tial oxi­da­tion is resolved by study­ing the under­ly­ing reac­tion­mech­a­nisms via mul­ti­scale mod­el­ing and com­par­i­son to micro­probe mass spec­ex­per­i­men­tal data.

Speaker’s Biog­ra­phy — Dr. Vla­chos is Pro­fes­sor at the Depart­ment of Chem­i­cal Engi­neer­ing atthe Uni­ver­si­ty of Delaware. He is cur­rent­ly the Drec­tor of the Cen­ter for Cat­alyt­ic­Science and Tech­nol­o­gy. His main research thrust is mul­ti­scale mod­el­ing and sim­u­la­tion­a­long with their appli­ca­tion to catal­y­sis and portable micro­chem­i­cal devices for pow­er­gen­er­a­tion, reform­ing of renew­ables and alter­na­tive fuels, cat­a­lyst informatics,microreactors, and process inten­si­fi­ca­tion.