PtFeCoNiCu High-Entropy Alloy Catalyst for Aqueous-Phase Hydrogenation of Maleic Anhydride

High-entropy alloys (HEAs), as new heterogeneous catalytic materials, possess remarkable catalytic performance in numerous reactions. However, rational and controllable synthesis of these complex structures remains a challenge. In this work, bulk and carbon nanotube (CNT)-supported ultrasmall PtFeCoNiCu HEA nanoparticles with an average particle size of 1.58 nm are prepared by lithium naphthalenide-driven reduction under mild conditions. The supported PtFeCoNiCu/CNT catalyst exhibits high catalytic activity in the aqueous-phase hydrogenation of maleic anhydride to succinic acid with a selectivity of 98% at full conversion of maleic acid (the hydrolysis product of maleic anhydride), a low apparent activation energy (Ea = 49 kJ mol-1), and excellent stability. Moreover, a much higher mass-specific activity of Pt in the catalyst is displayed over PtFeCoNiCu/CNT (1515.4 mmolmaleic acid gPt-1 h-1) than that of 5 wt % Pt/CNT (388.0 mmolmaleic acid gPt-1 h-1). This work provides a strong support for HEAs as advanced heterogeneous catalysts and will be of great significance for promoting the research and application of HEAs in the field of selective hydrogenation.

Automated summary

High-entropy alloys (HEAs) show remarkable catalytic performance in various reactions, but their synthesis with controlled structures remains a challenge. This study successfully prepared ultrasmall PtFeCoNiCu HEA nanoparticles supported on carbon nanotubes (CNTs) through a lithium naphthalenide-driven reduction method. The supported PtFeCoNiCu/CNT catalyst exhibited high catalytic activity, selectivity, low activation energy, and excellent stability in the hydrogenation reaction of maleic anhydride to succinic acid. Moreover, the mass-specific activity of Pt in this catalyst was much higher than that of Pt/CNT. This work provides strong support for HEAs as advanced heterogeneous catalysts and promotes further research and application in selective hydrogenation.