Selective hydrogenation of nitroaromatics catalyzed by surface Pt-rich high-entropy alloy catalysts at room temperature†

Abstract

The selective hydrogenation of nitroaromatics is a promising and environmentally friendly method for synthesizing the chemical intermediates of functionalized aromatic amines. However, achieving room-temperature hydrogenation remains a formidable challenge. In this study, we prepared a high-entropy alloy (HEA) catalyst with a similar core–shell structure, with a Pt-rich HEA as the shell and a CuNi-rich HEA as the core. This catalyst enables 100% conversion and selectivity for the hydrogenation of p-chloronitrobenzene under ambient temperature, in both solvent-involved and solvent-free systems. Additionally, it exhibits excellent stability, recyclability, and versatility. Furthermore, heat treatment-induced disruption of the Pt-rich surface structure leads to significant reduction in catalytic activity or even deactivation due to the migration of surface Pt atoms towards the interior of the alloy. These findings highlight the crucial role played by the Pt-rich surface structure in attaining outstanding performance in nitroaromatic hydrogenation. This work offers novel insights and strategies for designing efficient catalysts tailored specifically for selective nitroaromatic hydrogenation.