Computational study of CO2 methanation on Ru/CeO2 model surfaces: On the impact of Ru doping in CeO2

Lulu Chen; Ivo A.W. Filot; Emiel J.M. Hensen

doi:10.1021/acscatal.3c03742

Computational study of CO2 methanation on Ru/CeO2 model surfaces: On the impact of Ru doping in CeO2

Lulu Chen
, Ivo A.W. Filot
, Emiel J.M. Hensen (Corresponding author)

Research output: Contribution to journal › Article › Academic › peer-review

45 Citations (Scopus)

252 Downloads (Pure)

Abstract

The Sabatier reaction (CO ₂ + H ₂ → CH ₄ + H ₂O) can contribute to renewable energy storage by converting green H ₂ with waste CO ₂ into CH ₄. Highly dispersed Ru on CeO ₂ represents an active catalyst for the CO ₂ methanation. Here, we investigated the support effect by considering a single atom of Ru and a small Ru cluster on CeO ₂ (Ru ₆/CeO ₂). The influence of doping CeO ₂ with Ru was investigated as well (Ru ₆/RuCe _x-1O _2x-1). Density functional theory was used to compute the reaction energy diagrams. A single Ru atom on CeO ₂ can only break one of the C-O bonds in adsorbed CO ₂, making it only active in the reverse water-gas shift reaction. In contrast, Ru ₆ clusters on stoichiometric and Ru-doped CeO ₂ are active methanation catalysts. CO is the main reaction intermediate formed via a COOH surface intermediate. Compared to an extended Ru(11-21) surface containing step-edge sites where direct C-O bond dissociation is facile, C-O dissociation proceeds via H-assisted pathways (CO → HCO → CH) on Ru ₆/CeO ₂ and Ru ₆/RuCe _x-1O _2x-1. A higher CO ₂ methanation rate is predicted for Ru ₆/RuCe _x-1O _2x-1. Electronic structure analysis clarifies that the lower activation energy for HCO dissociation on Ru ₆/RuCe _x-1O _2x-1 is caused by stronger electron-electron repulsion due to its closer proximity to Ru. Strong H ₂ adsorption on small Ru clusters explains the higher CO ₂ methanation activity of Ru clusters on CeO ₂ compared to a Ru step-edge surface, representative of Ru nanoparticles, where the H coverage is low due to stronger competition with adsorbed CO.

Original language	English
Pages (from-to)	15230-15247
Number of pages	18
Journal	ACS Catalysis
Volume	13
Issue number	23
DOIs	https://doi.org/10.1021/acscatal.3c03742
Publication status	Published - 1 Dec 2023

Funding

We acknowledge the financial support granted by the China Scholarship Council. The authors acknowledge NWO and SurfSARA for providing computational resources to carry out the DFT calculations.

Funders
Nederlandse Organisatie voor Wetenschappelijk Onderzoek
China Scholarship Council

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 7 Affordable and Clean Energy

Keywords

CO2 methanation; ruthenium; CeO2; mechanism; density functional theory
ruthenium
density functional theory
CeO
CO methanation
mechanism

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title = "Computational study of CO2 methanation on Ru/CeO2 model surfaces: On the impact of Ru doping in CeO2",

abstract = "The Sabatier reaction (CO 2 + H 2 → CH 4 + H 2O) can contribute to renewable energy storage by converting green H 2 with waste CO 2 into CH 4. Highly dispersed Ru on CeO 2 represents an active catalyst for the CO 2 methanation. Here, we investigated the support effect by considering a single atom of Ru and a small Ru cluster on CeO 2 (Ru 6/CeO 2). The influence of doping CeO 2 with Ru was investigated as well (Ru 6/RuCe x-1O 2x-1). Density functional theory was used to compute the reaction energy diagrams. A single Ru atom on CeO 2 can only break one of the C-O bonds in adsorbed CO 2, making it only active in the reverse water-gas shift reaction. In contrast, Ru 6 clusters on stoichiometric and Ru-doped CeO 2 are active methanation catalysts. CO is the main reaction intermediate formed via a COOH surface intermediate. Compared to an extended Ru(11-21) surface containing step-edge sites where direct C-O bond dissociation is facile, C-O dissociation proceeds via H-assisted pathways (CO → HCO → CH) on Ru 6/CeO 2 and Ru 6/RuCe x-1O 2x-1. A higher CO 2 methanation rate is predicted for Ru 6/RuCe x-1O 2x-1. Electronic structure analysis clarifies that the lower activation energy for HCO dissociation on Ru 6/RuCe x-1O 2x-1 is caused by stronger electron-electron repulsion due to its closer proximity to Ru. Strong H 2 adsorption on small Ru clusters explains the higher CO 2 methanation activity of Ru clusters on CeO 2 compared to a Ru step-edge surface, representative of Ru nanoparticles, where the H coverage is low due to stronger competition with adsorbed CO.",

keywords = "CO2 methanation; ruthenium; CeO2; mechanism; density functional theory, ruthenium, density functional theory, CeO, CO methanation, mechanism",

author = "Lulu Chen and Filot, \{Ivo A.W.\} and Hensen, \{Emiel J.M.\}",

year = "2023",

month = dec,

day = "1",

doi = "10.1021/acscatal.3c03742",

language = "English",

volume = "13",

pages = "15230--15247",

journal = "ACS Catalysis",

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T1 - Computational study of CO2 methanation on Ru/CeO2 model surfaces

T2 - On the impact of Ru doping in CeO2

AU - Chen, Lulu

AU - Filot, Ivo A.W.

AU - Hensen, Emiel J.M.

PY - 2023/12/1

Y1 - 2023/12/1

N2 - The Sabatier reaction (CO 2 + H 2 → CH 4 + H 2O) can contribute to renewable energy storage by converting green H 2 with waste CO 2 into CH 4. Highly dispersed Ru on CeO 2 represents an active catalyst for the CO 2 methanation. Here, we investigated the support effect by considering a single atom of Ru and a small Ru cluster on CeO 2 (Ru 6/CeO 2). The influence of doping CeO 2 with Ru was investigated as well (Ru 6/RuCe x-1O 2x-1). Density functional theory was used to compute the reaction energy diagrams. A single Ru atom on CeO 2 can only break one of the C-O bonds in adsorbed CO 2, making it only active in the reverse water-gas shift reaction. In contrast, Ru 6 clusters on stoichiometric and Ru-doped CeO 2 are active methanation catalysts. CO is the main reaction intermediate formed via a COOH surface intermediate. Compared to an extended Ru(11-21) surface containing step-edge sites where direct C-O bond dissociation is facile, C-O dissociation proceeds via H-assisted pathways (CO → HCO → CH) on Ru 6/CeO 2 and Ru 6/RuCe x-1O 2x-1. A higher CO 2 methanation rate is predicted for Ru 6/RuCe x-1O 2x-1. Electronic structure analysis clarifies that the lower activation energy for HCO dissociation on Ru 6/RuCe x-1O 2x-1 is caused by stronger electron-electron repulsion due to its closer proximity to Ru. Strong H 2 adsorption on small Ru clusters explains the higher CO 2 methanation activity of Ru clusters on CeO 2 compared to a Ru step-edge surface, representative of Ru nanoparticles, where the H coverage is low due to stronger competition with adsorbed CO.

AB - The Sabatier reaction (CO 2 + H 2 → CH 4 + H 2O) can contribute to renewable energy storage by converting green H 2 with waste CO 2 into CH 4. Highly dispersed Ru on CeO 2 represents an active catalyst for the CO 2 methanation. Here, we investigated the support effect by considering a single atom of Ru and a small Ru cluster on CeO 2 (Ru 6/CeO 2). The influence of doping CeO 2 with Ru was investigated as well (Ru 6/RuCe x-1O 2x-1). Density functional theory was used to compute the reaction energy diagrams. A single Ru atom on CeO 2 can only break one of the C-O bonds in adsorbed CO 2, making it only active in the reverse water-gas shift reaction. In contrast, Ru 6 clusters on stoichiometric and Ru-doped CeO 2 are active methanation catalysts. CO is the main reaction intermediate formed via a COOH surface intermediate. Compared to an extended Ru(11-21) surface containing step-edge sites where direct C-O bond dissociation is facile, C-O dissociation proceeds via H-assisted pathways (CO → HCO → CH) on Ru 6/CeO 2 and Ru 6/RuCe x-1O 2x-1. A higher CO 2 methanation rate is predicted for Ru 6/RuCe x-1O 2x-1. Electronic structure analysis clarifies that the lower activation energy for HCO dissociation on Ru 6/RuCe x-1O 2x-1 is caused by stronger electron-electron repulsion due to its closer proximity to Ru. Strong H 2 adsorption on small Ru clusters explains the higher CO 2 methanation activity of Ru clusters on CeO 2 compared to a Ru step-edge surface, representative of Ru nanoparticles, where the H coverage is low due to stronger competition with adsorbed CO.

KW - CO2 methanation; ruthenium; CeO2; mechanism; density functional theory

KW - ruthenium

KW - density functional theory

KW - CeO

KW - CO methanation

KW - mechanism

UR - https://www.scopus.com/pages/publications/85178156679

U2 - 10.1021/acscatal.3c03742

DO - 10.1021/acscatal.3c03742

M3 - Article

SN - 2155-5435

VL - 13

SP - 15230

EP - 15247

JO - ACS Catalysis

JF - ACS Catalysis

IS - 23

ER -

Computational study of CO2 methanation on Ru/CeO2 model surfaces: On the impact of Ru doping in CeO2

Abstract

Funding

UN SDGs

Keywords

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