Fabrication of Nano-Structured Catalyst Supports by ALD

2018 Spring Symposium

Ray­mond J. GorteChem­i­cal & Bio­mol­e­c­u­lar Engi­neer­ing, Uni­ver­si­ty of Penn­syl­va­nia, Philadel­phia, PA

Abstract — Inter­ac­tions between a tran­si­tion-met­al cat­a­lyst and its sup­port can strong­ly alter the sta­bil­i­ty and activ­i­ty of the cat­a­lyst. Impor­tant exam­ples include sup­port effects with ceria and the so-called “Intel­li­gent Cat­a­lysts” in which the met­al can be redis­persed by reversible ex-solu­tion from a per­ovskite lat­tice. How­ev­er, the sur­face areas of these func­tion­al sup­ports are often too low or unsta­ble; and, in the case of per­ovskites, the length scales for ingress and egress may be too long to take advan­tage of the effect. We are address­ing these issues by deposit­ing very thin films of var­i­ous func­tion­al oxides, ~0.5 to 2 nm thick, onto high-sur­face-area sup­ports, includ­ing Al2O3 and MgAl2O4 , by Atom­ic Lay­er Depo­si­tion. We have demon­strat­ed that a wide range of oxides can be deposit­ed as dense, uni­form, con­for­mal films on var­i­ous sup­ports. The films exhib­it sur­pris­ing­ly good ther­mal sta­bil­i­ty and pro­vide cat­alyt­ic prop­er­ties sim­i­lar to that observed with bulk oxides, but with high­er sur­face areas.