The Elements Selection of High Entropy Alloy Guided by Thermodynamics and the Enhanced Electrocatalytic Mechanism for Oxygen Reduction Reaction

Abstract

Owing to their exceptional properties, high‐entropy alloys (HEAs) have received considerable attention in the field of electrocatalysis. However, few studies focus on the origin of their outstanding performance. Here, carbon‐supported PtFeCoNiMn (with an atomic ratio of 21:20:20:20:19) HEA nanoparticles via shock‐heating and shock‐cooling strategy are rationally designed and successfully prepared. The above five metal elements are rationally selected from the perspective of thermodynamics and geometric effects. Subsequently, the alloying process of the PtFeCoNiMn HEA is investigated via operando X‐ray diffraction characterizations. The electronic structures of each metal atom on the PtFeCoNiMn HEA and monometallic nanoparticles surface are revealed by density function theory calculations for illustrating the performance enhancement mechanism. It is found that Pt atoms on the PtFeCoNiMn HEA surface exhibit a wider range of d‐band center distribution range than the corresponding monometallic nanoparticles, which contributes to the enhanced selective adsorption of O2 reactants/intermediates. Importantly, some Fe, Co, Ni, and Mn atoms on the HEA surface manifest less positive d‐band center values than the corresponding monometallic nanoparticles, with similar d‐band center positions to some Pt atoms. This indicates that the inactive atoms in monometallic nanoparticles can be transformed into ORR active sites in the HEA matrix owing to the electronic interaction between adjacent atoms.

Noble‐Metal‐Free High‐Entropy Alloy Nanoparticles for Efficient Solar‐Driven Photocatalytic CO2 Reduction

“…As depicted in Figure 2b, the HEA NPs exhibit an average diameter of 3.5 ± 0.2 nm, while Figure 2c shows a lattice spacing of 0.221 nm, corresponding to the (111) plane. [22] Energy-dispersive X-ray spectroscopy mapping (Figure 2d-i emission spectroscopy (ICP-AES), as presented in Figure S3, Supporting Information. Taken together, these structural results provide conclusive evidence for the successful formation of FeCoNiCuMn HEA NPs.…”

NiCoCrFeY High Entropy Alloy Nanopowders and Their Soft Magnetic Properties

“…High entropy alloys break through the limitations of traditional alloy components, and by adjusting the combination and content of multiple components, they are endowed with excellent mechanical and magnetic properties [7], such as high strength [8][9][10], high toughness [11][12][13], high hardness [14], corrosion resistance [15][16][17], and radiation resistance [18], and have shown great potential for application in many fields [19][20][21][22][23][24][25]. There are three main representative types of high entropy alloys: Cantor alloys (CoCrFeMnNi), which are dominated by 3d transition group metals; Senkov alloys (NbMoTaW), which are dominated by refractory metals; and low density, high entropy alloys (AlMgLiZnCu, AlMgZnCuSi, AlZrTiNbMo) [26,27], which are dominated by lightweight elements, such as aluminium, magnesium and titanium. Among them, Cantor alloys are based on three ferromagnetic elements, Fe, Co and Ni, and one or more non-ferromagnetic elements, such as antiferromagnetic Cr, antimagnetic Cu, Si, Ga, paramagnetic Al, Ti, Mn, Sn, etc., are added in trace amounts to improve the magnetic and mechanical properties of the alloys, so as to obtain high entropy soft magnetic materials with excellent comprehensive performance [13,28,29].…”

Unraveling Reactivity Origin of Oxygen Reduction at High-Entropy Alloy Electrocatalysts with a Computational and Data-Driven Approach

“…For instance, Pedersen et al highlighted that traversing from simple Pt alloys to HEAs broadens the distribution of the binding energies of key reaction intermediates (e.g., *OH), increasing the likelihood of achieving optimal binding properties that align with the activity volcanoes . Numerous experimental investigations have underscored the significant promise of HEAs as ORR electrocatalysts. − With a low-temperature solution-based approach, He et al synthesized a CrMnFeCoNi HEA that demonstrated an exceptional ORR efficiency, showcasing a half-wave potential of 0.78 V and an onset potential of 0.88 V vs RHE, rivaling that of commercial Pt/C catalysts . In another study, Li et al crafted an AlCuNiPtMn HEA with a modest Pt content of approximately 20–30 at % while exhibiting improved durability and ORR activity in comparison to commercial Pt/C .…”