High throughput screening of noble Metal-Free High-Entropy alloys catalysts for selective catalytic oxidation of NH3

Abstract

The high price and scarcity of Pt require the development of alternative low-cost catalysts for selective catalytic oxidation of ammonia (NH3-SCO). This work uses first-principles-based high-throughput calculations to evaluate noble metal-free high-entropy alloys (NMF-HEAs) as potential NH3-SCO candidate catalysts to replace Pt. Firstly, by employing empirical rules to determine the formation probability of single-phase solid solution, 350 NMF-HEAs are found to be single-phase solid solution among the vast configuration space (about 104) consisting of 20 non-noble metals. Among these, NMF-HEAs containing Cu and Zn elements are identified as promising catalysts based on the reactivity and selectivity rules of the NH3-SCO process. Further analysis of elemental composition and distribution on configurations with N-atom adsorption energies reveals that the co-existence of Cu and Zn elements and the symmetric distribution of surface atoms is conducive to tuning N-binding ability in the optimal region. Finally, full reaction paths of NH3-SCO processes on the optimal CuZnNiMoCo HEA are calculated and confirm their activity comparable to that of Pt catalysts and better selectivity. This study gains insight into the effects of the composition and surface configuration of HEAs on the NH3-SCO process and provides a theoretical framework for designing and optimizing efficient catalysts of the NH3-SCO process.