Experimental and theoretical investigation of high-entropy-alloy/support as a catalyst for reduction reactions

Control of chemical composition and incorporation of multiple metallic elements into a single metal nanoparticle (NP) in an alloyed or a phase-segregated state hold potential scientific merit; however, developing libraries of such structures using effective strategies is challenging owing to the thermodynamic immiscibility of repelling constituent metallic elements. Herein, we present a one-pot interfacial plasma–discharge-driven (IP-D) synthesis strategy for fabricating stable high-entropy-alloy (HEA) NPs exhibiting ultrasmall size on a porous support surface. Accordingly, an electric field was applied for 120 s to enhance the incorporation of multiple metallic elements (i.e., CuAgFe, CuAgNi, and CuAgNiFe) into ally HEA-NPs. Further, NPs were attached to a porous magnesium oxide surface via rapid cooling. With solar light as the sole energy input, the CuAgNiFe catalyst was investigated as a reusable and sustainable material exhibiting excellent catalytic performance (100% conversion and 99% selectivity within 1 min for a hydrogenation reaction) and consistent activity even after 20 cycles for a reduction reaction, considerably outperforming the majority of the conventional photocatalysts. Thus, the proposed strategy establishes a novel method for designing and synthesizing highly efficient and stable catalysts for the convertion of nitroarenes to anilines via chemical reduction.