Abstract
Co-electrolysis of carbon oxides and nitrogen oxides promise to simultaneously help restore the balance of the C and N cycles while producing valuable chemicals such as urea. However, co-electrolysis processes are still largely inefficient and numerous knowledge voids persist. Here, we provide a solid thermodynamic basis for modelling urea production via co-electrolysis. First, we determine the energetics of aqueous urea produced under electrochemical conditions based on experimental data, which enables an accurate assessment of equilibrium potentials and overpotentials. Next, we use density functional theory (DFT) calculations to model various co-electrolysis reactions producing urea. The calculated reaction free energies deviate significantly from experimental values for well-known GGA, meta-GGA and hybrid functionals. These deviations stem from errors in the DFT-calculated energies of molecular reactants and products. In particular, the error for urea is approximately -0.25 ± 0.10 eV. Finally, we show that all these errors introduce large inconsistencies in the calculated free-energy diagrams of urea production via co-electrolysis, such that gas-phase corrections are strongly advised.
| Original language | English |
|---|---|
| Article number | 196 |
| Number of pages | 10 |
| Journal | Communications Chemistry |
| Volume | 6 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 13 Sept 2023 |
Bibliographical note
Funding Information:This work received financial support from grants PID2021-127957NB-I00 and TED2021-132550B-C21, which are funded by MCIN/AEI/ 10.13039/501100011033 and the European Union. The project that gave rise to these results also received the support of a Ph.D. fellowship from “la Caixa” Foundation (ID 100010434, fellowship code LCF/BQ/DI22/11940040). FI and STB MdM acknowledge funding from the ‘María de Maeztu’ program for Spanish Structures of Excellence (CEX2021-001202-M). We thank Red Española de Supercomputación (RES) for supercomputingtime at Marenostrum 4 (project QHS-2023-2-0013). The use of supercomputing facilities at SURFsara was sponsored by NWO Physical Sciences, with financial support by NWO. We also acknowledge the use of supercomputing resources of the Centro de Computación Científica Apolo at Universidad EAFIT ( https://www.eafit.edu.co/apolo ) and the Center for Functional Nanomaterials, which is a U.S. DOE Office of Science User Facility, and the Scientific Data and Computing Center, a component of the Computational Science Initiative, at Brookhaven National Laboratory under contract no. DE-SC0012704.