Self-regeneration of supported transition metals by a high entropy-driven principle.

Hou, Shengtai; Ma, Xuefeng; Shu, Yuan; Bao, Jiafeng; Zhang, Qiuyue; Chen, Mingshu; Zhang, Pengfei; Dai, Sheng · Nat Commun · 2021

basic_science · Level V

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Abstract

The sintering of Supported Transition Metal Catalysts (STMCs) is a core issue during high temperature catalysis. Perovskite oxides as host matrix for STMCs are proven to be sintering-resistance, leading to a family of self-regenerative materials. However, none other design principles for self-regenerative catalysts were put forward since 2002, which cannot satisfy diverse catalytic processes. Herein, inspired by the principle of high entropy-stabilized structure, a concept whether entropy driving force could promote the self-regeneration process is proposed. To verify it, a high entropy cubic Zr<sub>0.5</sub>(NiFeCuMnCo)<sub>0.5</sub>O<sub>x</sub> is constructed as a host model, and interestingly in situ reversible exsolution-dissolution of supported metallic species are observed in multi redox cycles. Notably, in situ exsolved transition metals from high entropy Zr<sub>0.5</sub>(NiFeCuMnCo)<sub>0.5</sub>O<sub>x</sub> support, whose entropic contribution (TΔS<sub>config</sub> = T⋆12.7 J mol<sup>-1</sup> K<sup>-1</sup>) is predominant in ∆G, affording ultrahigh thermal stability in long-term CO<sub>2</sub> hydrogenation (400 °C, >500 h). Current theory may inspire more STWCs with excellent sintering-resistance performance.