Ibrahim, Abdulrauf Onimisi and Wan Daud, Wan Mohd Ashri and Abdul Patah, Muhamad Fazly and Halilu, Ahmed and Juan, Joon Ching and Tanimu, Gazali (2024) A microkinetic study of CO2 hydrogenation to methanol on Pd1-Cu(111) and Pd1-Ag(111) catalysts: a DFT analysis. Physical Chemistry Chemical Physics, 26 (14). pp. 10622-10632. ISSN 1463-9076, DOI https://doi.org/10.1039/d4cp00070f.
Full text not available from this repository.Abstract
The thermochemical conversion of CO2 into methanol, a process known for its selectivity, often encounters a significant obstacle: the reverse water gas reaction. This problem emerges due to the demanding high temperatures and pressures, causing instability in catalytic performance. Recent endeavours have focused on innovatively designing catalysts capable of withstanding such conditions. Given the costliness of experimental approaches, a theoretical framework has emerged as a promising avenue for addressing the challenges in methanol production. It has been reported that transition metals, especially Pd, provide ideal binding sites for CO2 molecules and hydrogen atoms, facilitating their interactions and subsequent conversion to methanol. In the geometric single-atom form, their surface enables precise control over the reaction pathways and enhances the selectivity towards methanol. In our study, we employed density functional theory (DFT) to explore the conversion of CO2 to CH3OH on Pd1-Cu(111) and Pd1-Ag(111) single-atom alloy (SAA) catalysts. Our investigation involved mapping out the complex reaction pathways of CO2 hydrogenation to CH3OH using microkinetic reaction modelling and mechanisms. We examined three distinct pathways: the COOH* formation pathway, the HCOO* formation pathway, and the dissociation of CO2* to CO* pathway. This comprehensive analysis encompassed the determination of adsorption energies for all reactants, transition states, and resultant products. Additionally, we investigated the thermodynamic and kinetic profiles of individual reaction steps. Our findings emphasised the essential role of the Pd single atom in enhancing the activation of CO2, highlighting the key mechanism underlying this catalytic process. The favoured route for methanol generation on the Pd1-Ag(111) single-atom alloy (SAA) surface unfolds as follows: CO2* progresses through a series of transformations, transitioning successively into HCOO*, HCOOH*, H2COOH*, CH2O*, and CH2OH*, terminating in the formation of CH3OH*, due to lower activation energies and higher rate constants.
| Item Type: | Article |
|---|---|
| Funders: | Petroleum Technology Development Fund (PTDF/ED/OSS/PHD/AOI/1459/19), Petroleum Technology Development Fund, Nigeria |
| Uncontrolled Keywords: | Gas Shift Reaction; CU/ZRO2 Catalysis; Mechanism; Precursor; Surface; ZRO2 |
| Subjects: | T Technology > TP Chemical technology |
| Divisions: | Faculty of Engineering > Department of Chemical Engineering Deputy Vice Chancellor (Research & Innovation) Office > Nanotechnology & Catalysis Research Centre |
| Depositing User: | Ms. Juhaida Abd Rahim |
| Date Deposited: | 22 Oct 2024 05:41 |
| Last Modified: | 22 Oct 2024 05:41 |
| URI: | http://eprints.um.edu.my/id/eprint/45463 |
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