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Title: Potassium-induced effect on structure and chemical activity of CuxO/Cu(111) (x≤2) surface: A combined scanning tunneling microscopy and density functional theory study

Potassium (K) plays an essential role in promoting catalytic reaction in many established industrial catalytic processes. Here, we report a combined study using scanning tunneling microscopy (STM) and density functional theory (DFT) in understanding the effect of depositing K on the atomic and electronic structures as well as chemical activities of CuxO/Cu(111) (x≤2). The DFT calculations observe a pseudomorphic growth of K on CuxO/Cu(111) up to 0.19 monolayer (ML) of coverage, where K binds the surface via strong ionic interaction with chemisorbed oxygen and the relatively weak electrostatic interactions with copper ions, lower and upper oxygen on the CuxO rings. The simulated STM pattern based on the DFT results agrees well with the experimental observations. The deposited K displays great impact on the surface electronic structure of CuxO/Cu(111), which induces significant reduction in work function and leads to a strong electron polarization on the surface. The promotion of K on the surface binding properties is selective. It varies depending on the nature of adsorbates. According to our results, K has little effect on surface acidity, while it enhances the surface basicity significantly. As a consequence, the presence of K does not help for CO adsorption on CuxO/Cu(111), but being ablemore » to accelerate the activation of CO2. Thus, such promotion strongly depends on the combinations from both geometric and electronic effects. Our results highlight the origin of promoting effect of alkalis in the design of catalysts for the complex reactions.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States); Shanghai Univ. of Engineering Science, Shanghai (China)
  3. Stony Brook Univ., Stony Brook, NY (United States)
Publication Date:
OSTI Identifier:
1224792
Report Number(s):
BNL--108537-2015-JA
Journal ID: ISSN 1867-3880; R&D Project: CO-019; KC0302010
Grant/Contract Number:
SC00112704
Type:
Accepted Manuscript
Journal Name:
ChemCatChem
Additional Journal Information:
Journal Volume: 115; Journal Issue: 19; Journal ID: ISSN 1867-3880
Publisher:
ChemPubSoc Europe
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
30 DIRECT ENERGY CONVERSION potassium; electron polarization; CO2; copper oxide; DFT; STM; Center for Functional Nanomaterials