(509f) Computational Investigation into Supported and Inverted Cu/ZrO2 Catalysts for Selective Conversion of CO2 to Methanol

Greenhouse gases like CO_2, which are produced from fossil fuel burning, have proven to be a primary reason for global warming and climate change. The carbon-neutral conversion of CO₂ to methanol, using renewable hydrogen, provides a sustainable and lucrative technology for combating CO₂ emissions¹_. The Cu/ZrO₂ catalytic system has been extensively investigated for the above chemistry, owing to its excellent stability and selectivity towards methanol³_. More recently, the inverted ZrO₂/Cu catalysts have shown to have better selectivity performance than the supported system for CO₂ hydrogenation^4,5 _. However, the nature of active sites and synergistic effect between the Cu and ZrO₂ components remains elusive.

In this work, we utilize Density Functional Theory (DFT) calculations to study atomistic models representing supported and inverted Cu-ZrO₂ systems. We elucidate charge transfer characteristics as well as thermodynamic stability of both systems under operando conditions. We find that the formation of oxygen vacancies, prominently around interfacial locations, is most feasible under hydrogen pre-treatment conditions, prior to introducing CO₂ at the inlet. We compute adsorption energies of intermediates relevant to CO₂ hydrogenation and demonstrate that the presence of oxygen vacancies leads to additional stabilization of all species on both systems, further enabling the mechanistic pathways for hydrogenation (Figure 1). The selectivity performance of inverted systems towards is shown to be higher than supported system, owing to the excess stabilization of adsorbed CO on the former compared to the latter.

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2. Li et al. ACS Catal 9, 7840–7861 (2019).
3. Rui et al. Ind Eng Chem Res 60, 18900–18906 (2021).
4. Wu et al. Nat Commun 11, (2020).
5. Duyar et al. Angewandte Chemie 130, 15265–15270 (2018).