Title: CO₂ Hydrogenation to Methanol over Inverse ZrO₂/Cu(111) Catalysts: The Fate of Methoxy under Dry and Wet Conditions

Abstract

Understanding the surface chemistry of CH₃O species is essential for the production of methanol by CO₂ hydrogenation over Cu-based heterogeneous catalysts, as it facilitates the rational design of more efficient conversion processes. Recent research has identified inverse ZrO₂/Cu catalysts as highly active and selective systems for the transformation of CO₂ to methanol with a performance that can be better than that of commercial Cu/ZnO catalysts. Here, we employed synchrotron-based ambient pressure X-ray photoelectron spectroscopy (AP-XPS) and calculations based on density functional theory (DFT) to understand the fate of CH₃O groups under dry and wet environments. AP-XPS spectra revealed that under CO₂ hydrogenation conditions, formate and methoxy are two key intermediates to produce methanol. Furthermore, there are three different types of reactive sites on the surface: One is active for methoxy adsorption, which is stable and responsible for the methanol synthesis; Another one transforms CO₂ into CO; and a third one is active for CO₂ and methoxy dissociation, leading to C and methane formation. The theoretical calculations indicate that CH₃OH readily dissociates to CH₃O species following a highly exothermic (ΔE = -20.99 kcal/mol) and barrierless process. The water produced by the reverse water-gas shift reaction (CO₂ + H₂ → H₂O +more » CO) can prevent the decomposition of CH₃O species. We discovered that by introducing a tiny amount of water vapor (2 × 10^-6 Torr) into the reaction chamber, the energy barrier for the reaction CH₃O(ads) + H(ads) → CH₃OH(gas) is dramatically reduced. AP-XPS and computational modelling showed that water is quite capable of extracting adsorbed methoxy to form gaseous methanol. With this in mind, one could boost the methanol selectivity by adding appropriate amounts of water or steam, which is an inexpensive and feasible solution for industrial operations.« less

Authors:

Rui, Ning  ^[1];

• Search DOE PAGES for author "Rui, Ning"
• Search DOE PAGES for ORCID "0000-0001-6234-7075"

Huang, Erwei  ^[2];

• Search DOE PAGES for author "Huang, Erwei"
• Search DOE PAGES for ORCID "0000-0003-2690-3788"

Kim, Jeongjin ^[1]; Mehar, Vikram ^[1]; Shi, Rui ^[2]; Rosales, Rina ^[2]; Tian, Yi ^[2]; Hunt, Adrian  ^[1];

• Search DOE PAGES for author "Hunt, Adrian"
• Search DOE PAGES for ORCID "0000-0002-5283-9647"

Waluyo, Iradwikanari  ^[1];

• Search DOE PAGES for author "Waluyo, Iradwikanari"
• Search DOE PAGES for ORCID "0000-0002-4046-9722"

Senanayake, Sanjaya D.  ^[1];

• Search DOE PAGES for author "Senanayake, Sanjaya D."
• Search DOE PAGES for ORCID "0000-0003-3991-4232"

Liu, Ping  ^[3];

• Search DOE PAGES for author "Liu, Ping"
• Search DOE PAGES for ORCID "0000-0001-8363-070X"

Rodriguez, José A.  ^[3]

• Search DOE PAGES for author "Rodriguez, José A."
• Search DOE PAGES for ORCID "0000-0002-5680-4214"

---

+ Show Author Affiliations

1. Brookhaven National Lab. (BNL), Upton, NY (United States)
2. Stony Brook Univ., NY (United States)
3. Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., NY (United States)

Publication Date:

Thu Aug 18 00:00:00 EDT 2022

Research Org.:

Brookhaven National Laboratory (BNL), Upton, NY (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)

OSTI Identifier:

1885781

Report Number(s):

BNL-223281-2022-JAAM
Journal ID: ISSN 1932-7447

Grant/Contract Number:  

SC0012704; AC02-05CH11231; #1531492

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Physical Chemistry. C

Additional Journal Information:

Journal Volume: 126; Journal Issue: 34; Journal ID: ISSN 1932-7447

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; carbon dioxide; methanol; zirconia; copper oxide; water; alcohols; catalysts; hydrocarbons; hydrogenation; organic reactions