Sulfur-Stabilizing Ultrafine High-Entropy Alloy Nanoparticles on MXene for Highly Efficient Ethanol Electrooxidation.

Peng, Wei; Lu, Ying-Rui; Lin, Haiping; Peng, Ming; Chan, Ting-Shan; Pan, Anlian; Tan, Yongwen · ACS Nano · 2023

basic_science · Level V

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Abstract

High-entropy alloys (HEAs) are significantly promising candidates for heterogeneous catalysis, yet the controllable synthesis of ultrafine HEA nanoparticles (NPs) remains a formidable challenge due to severe thermal sintering during the high-temperature fabrication process. Herein, we report a sulfur-stabilizing strategy to construct ultrafine HEA NPs with an average diameter of 4.02 nm supported on sulfur-modified Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> (S-Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub>) MXene, on which the strong interfacial metal-sulfur interactions between HEA NPs and the S-Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> supports significantly increase the interfacial adhesion strength, thus greatly suppressing nanoparticle sintering by retarding both particle migration and metal atom diffusion. The representative quinary PtPdCuNiCo HEA-S-Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> exhibits excellent catalytic performance toward alkaline ethanol oxidation reaction (EOR) with an ultrahigh mass activity of 7.03 A mg<sub>Pt+Pd</sub><sup>-1</sup>, which is 4.34 and 5.17 times higher than those of the commercial Pt/C and Pd/C catalysts, respectively. In situ attenuated total reflection-infrared spectroscopy studies reveal that the high intrinsic catalytic activity for the EOR can be ascribed to the synergy of different catalytically active sites of HEA NPs and the well-designed interfacial metal-sulfur interactions.