Title: Promotion of catalytic selectivity on transition metal oxide through restructuring surface lattice

Abstract

Pursuit of high catalytic selectivity is paramount in the design of catalysts for green chemical processes towards minimizing the production of undesired products. We demonstrated that catalytic selectivity for production of alkene through oxidative dehydrogenation of alkane on transition metal oxides can be promoted through tailoring the surface lattice of the oxide catalyst. Selectivity for production of ethylene through oxidative dehydrogenation (ODH) of ethane on Co₃O₄ nanocrystals can be substantially increased by 30%–35% via temperature-mediated reconstruction of surface lattice of Co₃O₄. Co₃O₄ nanocrystals formed at 800 °C leads to smooth, flat crystal plane with predominantly exposed (111) facet in contrast to high Miller index (311) facet of Co₃O₄ formed at ≤700 °C, revealed by environmental transmission electron microscopy. Isotope-labelled experiments suggest that the higher catalytic selectivity on the (111) facet results from the lower activity of its surface lattice oxygen atoms. Consistent with these experimental results, DFT calculations suggest low activity of surface lattice oxygen atoms and high activation barriers for adsorption and dissociation of C—H bond on the (111) surface in contrast to (311). Upon the activation of C—H on (311), the stronger binding of ethylene on more active, under-coordinated surface lattice oxygen atoms of (311) forms a robustmore » “deprotonated ethylene glycol”-like intermediate on (311) with a rate-limiting desorption barrier to the formation of ethylene. Compared to (311), the kinetically favorable desorption of bound ethylene species from (111) surface well rationalized the higher selectivity for production of ethylene on (111) than (311). Here these findings demonstrate that temperature-mediated tailoring of the surface lattice for a transition metal oxide nanocatalyst is a promising approach in pursuing high selectivity in oxidative dehydrogenation of hydrocarbons.« less

Authors:

Liu, Juanjuan ^[1]; Fung, Victor ^[2]; Wang, Yong ^[3]; Du, Kaimin ^[3]; Zhang, Shiran ^[4]; Nguyen, Luan ^[4]; Tang, Yu ^[4]; Fan, Jie ^[3]; Jiang, De-en ^[2]; Tao, Franklin Feng ^[4]

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+ Show Author Affiliations

1. University of Kansas, Lawrence, KS (United States); Zhejiang University, Hangzhou (China); Hangzhou Dianzi University (China)
2. University of California, Riverside, CA (United States)
3. Zhejiang University, Hangzhou (China)
4. University of Kansas, Lawrence, KS (United States)

Publication Date:

Sat May 12 00:00:00 EDT 2018

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Univ. of Kansas, Lawrence, KS (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB); National Natural Science Foundation of China (NSFC); USDOE

OSTI Identifier:

1543507

Alternate Identifier(s):

OSTI ID: 1602567

Grant/Contract Number:  

SC0014561; 21703050; 91545113

Resource Type:

Accepted Manuscript

Journal Name:

Applied Catalysis. B, Environmental

Additional Journal Information:

Journal Volume: 237; Journal Issue: C; Journal ID: ISSN 0926-3373

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

42 ENGINEERING; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; cobalt oxide; selectivity; surface faceting; oxygen vacancies