Publication | Open Access
Designing water resistant high entropy oxide materials
33
Citations
53
References
2024
Year
The ubiquitous presence of moisture usually shows adverse effects on industrial catalysis. Herein, a concept of engineering entropy to design water-resistant oxide catalysts is proposed. The C<sub>3</sub>H<sub>6</sub> oxidation by spinel ACr<sub>2</sub>O<sub>4</sub> (A=Ni, Mg, Cu, Zn, Co) catalysts is selected as a model. Through DFT calculation, the adsorption energy of C<sub>3</sub>H<sub>6</sub>, the dissociation energy of molecular H<sub>2</sub>O on the oxide surface, and the formation energy of oxygen vacancy all suggest better performance induced by higher configurational entropy. Indeed, (Ni<sub>0.2</sub>Mg<sub>0.2</sub>Cu<sub>0.2</sub>Zn<sub>0.2</sub>Co<sub>0.2</sub>)Cr<sub>2</sub>O<sub>4</sub> experimentally show excellent water resistance (>100 h) in C<sub>3</sub>H<sub>6</sub> oxidation, while in sharp contrast binary oxides (e.g., NiCr<sub>2</sub>O<sub>4</sub>, CoCr<sub>2</sub>O<sub>4</sub>) are deactivated in 20 h. H<sub>2</sub>O-TPD, in-situ Raman, and in-situ FTIR all confirm the low H<sub>2</sub>O adsorption energy and strong hydrothermal stability of high entropy oxide, which is attributed to their lower Gibbs free energy. This work may inspire the rational design of water-resistant catalysts.
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