Hydroxylation of ZnO/Cu(1 1 1) inverse catalysts under ambient water vapor and the water–gas shift reaction
- State Univ. of New York (SUNY) at Stony Brook, NY (United States). Dept. of Chemistry
- Universidad Central de Venezuela, Caracas (Venezuela)
- Brookhaven National Lab. (BNL), Upton, NY (United States). Dept. of Chemistry
- State Univ. of New York (SUNY) at Stony Brook, NY (United States). Dept. of Materials Science and Engineering
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
- State Univ. of New York (SUNY) at Stony Brook, NY (United States). Dept. of Chemistry; Brookhaven National Lab. (BNL), Upton, NY (United States). Dept. of Chemistry
- State Univ. of New York (SUNY) at Stony Brook, NY (United States). Dept. of Chemistry; Brookhaven National Lab. (BNL), Upton, NY (United States). Dept. of Chemistry; State Univ. of New York (SUNY) at Stony Brook, NY (United States). Dept. of Materials Science and Engineering
The interaction of water vapor with ZnO/CuOx/Cu(1 1 1) surfaces was explored using synchrotron-based ambient pressure x-ray photoelectron spectroscopy (AP-XPS) and density-functional theory (DFT) calculations. Cu(1 1 1) does not dissociate the water molecule. Cleavage of O–H bonds was seen with AP-XPS after depositing ZnO or preparing CuOx on the copper substrate. The findings of DFT calculations show unique behavior for ZnO/CuOx/Cu(1 1 1), not seen on Cu(1 1 1), CuOx/Cu(1 1 1) or ZnO(0 0 0). The ZnO/CuOx/Cu(1 1 1) system binds water quite well and exhibits the lowest energy barrier for O–H bond cleavage. The presence of unsaturated Zn cations in the islands of ZnO led to high chemical reactivity. In order to remove the OH from ZnO/CuOx/Cu(1 1 1) and ZnO/Cu(1 1 1) surfaces, heating to elevated temperatures was necessary. At 500–600 K, a significant coverage of OH groups was still present on the surfaces and did react with CO during the water–gas shift (WGS) process. The final state of the sample depended strongly on the amount of ZnO present on the catalyst surface. For surfaces with a ZnO coverage below 0.3 ML, the adsorption of water did not change the integrity of the ZnO islands. On the other hand, for surfaces with a ZnO coverage above 0.3 ML, a ZnO→ZnxOH transformation was observed. This transformation led to a decrease in the WGS catalytic activity.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0012704; AC02-05CH11231
- OSTI ID:
- 1566290
- Alternate ID(s):
- OSTI ID: 1656528
- Report Number(s):
- BNL-212106-2019-JAAM; TRN: US2000984
- Journal Information:
- Journal of Physics. D, Applied Physics, Vol. 52, Issue 45; ISSN 0022-3727
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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