High-Entropy Strategies Afford Transition Metal Perovskite Oxides with Enhanced Low-Temperature NOx Removal Efficiency

"High-entropy exclusion" and "elementary substitution" strategies are developed to afford high-entropy perovskites (HEPs) for NH3-SCR reaction at low-temperature. Among the six metals (Mn, Fe, Co, Ni, Cr, Al), HEP-no-Al exhibits the highest catalytic activity. It was found that the rich valence states of the elements at the B-site played a crucial role in enhancing the catalytic performance. Cr at the B-site was substituted with Mo and W, and B-site substitution by Mo further improves the NO removal efficiency to 100% at 180 °C.