Autocatalytic Formation of High‐Entropy Alloy Nanoparticles

Broge, Nils Lau Nyborg; Bondesgaard, Martin; Søndergaard‐Pedersen, Frederik; Roelsgaard, Martin; Iversen, Bo B.

doi:10.1002/anie.202009002

Cited by 70 publications

(62 citation statements)

References 43 publications

(28 reference statements)

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“…S4). This is the smallest nanoparticle size for HEAs reported in the references [9,11,30,31]. This facilitates exposing more reactive sites for the electrocatalytic process due to the large specific surface area (Table S2).…”

Section: Articles Science China Materialsmentioning

confidence: 99%

Tailoring lattice strain in ultra-fine high-entropy alloys for active and stable methanol oxidation

et al. 2021

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High-entropy alloys (HEAs) have been widely studied due to their unconventional compositions and unique physicochemical properties for various applications. Herein, for the first time, we propose a surface strain strategy to tune the electrocatalytic activity of HEAs for methanol oxidation reaction (MOR). High-resolution aberration-corrected scanning transmission electron microscopy (STEM) and elemental mapping demonstrate both uniform atomic dispersion and the formation of a face-centered cubic (FCC) crystalline structure in PtFeCoNiCu HEAs. The HEAs obtained by heat treatment at 700°C (HEA-700) exhibit 0.94% compressive strain compared with that obtained at 400°C (HEA-400). As expected, the specific activity and mass activity of HEA-700 is higher than that of HEA-400 and most of the state-of-the-art catalysts. The enhanced MOR activity can be attributed to a shorter Pt-Pt bond distance in HEA-700 resulting from compressive strain. The nonprecious metal atoms in the core could generate compressive strain and down shift d-band centers via electron transfer to surface Pt layer. This work presents a new perspective for the design of high-performance HEAs electrocatalysts.

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Section: Articles Science China Materialsmentioning

confidence: 99%

Tailoring lattice strain in ultra-fine high-entropy alloys for active and stable methanol oxidation

et al. 2021

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“…Under the hydrothermal treatment at 120°C, the first molecule of acetylacetone metal salt dissociates to produce a chain autocatalytic reaction, which spontaneously forms randomly distributed M 1 OM 2 bonds (corresponding to the process of rapid nucleation to form solid nanosphere within the initial 5 min, Figure 2c). [42] Secondly, other acetylacetone groups then successively added onto M 1 OM 2 bonds which forms…”

Section: Experimental Synthesis and Characterizations Of Heosmentioning

confidence: 99%

Battery‐Driven N₂ Electrolysis Enabled by High‐Entropy Catalysts: From Theoretical Prediction to Prototype Model

Sun

et al. 2022

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decentralized manner for local consumption, which can reduce the significant cost for massive storage, transport, and related processes. [6,7] Recent research shows that electrochemistry is an enabling technology for this purpose as it is relatively simple to scale electrolytic devices to meet almost any level of demand. [2,5,8] Particularly, water (H 2 O) and nitrogen (N 2 ) could be used as eco-friendly precursors to produce NH 3 in an electrolytic cell (N 2 + 3H 2 O → 2NH 3 + 3/2O 2 ). [6,9] If this electricity is provided by renewable energy systems such as rechargeable batteries driven by solar and wind, then the only input for this process would be supplies of H 2 O, N 2 and renewables. However, the design of such a small-scale, standalone prototype models (i.e., battery-driven N 2 electrolysis) has met with significant challenges.In an N 2 electrolytic cell, the system is composed of two half-reactions, i.e., anodic oxygen evolution reaction (OER, 6OH − → 3/2O 2 + 3H 2 O + 6e: E 0 = 1.23 V vs RHE) and cathodic N 2 reduction reaction (NRR, N 2 + 6H 2 O + 6e → 2NH 3 + 6OH − : E 0 = 0.227 V vs RHE), which is often complicated by side hydrogen evolution reaction (HER, 2H 2 O + 2e → H 2 + 2OH − ) that thermodynamically competes with NRR. [4,10] Consequently, the N 2 electrolysis is restricted by high overpotentials due to four-electron-transfer OER and six-electron-transfer NRR, which requires significant external applied voltages (>1.5 V for batteries)) to drive the ten-electron-transfer reaction efficiently. Consequently, enthusiastic efforts have been devoted to exploring active electrocatalysts to promote the reaction kinetics of NRR and OER, including both molecular and heterogeneous catalysts. [5,[11][12][13] Molecular catalysts have the advantage of highly exposed active sites, but tend to deactivate during electrochemical cycling. [14,15] In contrast, heterogeneous catalysts (such as perovskites, [16] NiFe-nanomeshes, [10] metal oxides [17] ) are more structurally stable, and can easily interface with electrode systems. Thus far, most of the reported catalysts are composed of one to ternary metals or non-metals. [16][17][18] Although these catalysts are desirable candidates for catalyzing simple proton/ electron transfer reactions, they generally do not perform well for reactions involving multi-step reaction paths, especially in combination of NRR and OER with ten electron-transfer processes. [19] High-entropy (HE) materials, particularly high-entropy oxides (HEOs), represent a class of materials made up of more A small-scale standalone device of nitrogen (N 2 ) splitting holds great promise for producing ammonia (NH 3 ) in a decentralized manner as the compensation or replacement of centralized Haber-Bosch process. However, the design of such a device has been impeded by sluggish kinetics of its half reactions, i.e., cathodic N 2 reduction reaction (NRR) and anodic oxygen evolution reaction (OER). Here, it is predicted from density function theory that high-entropy oxides (HEOs) are potential catalyst...

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“…Therefore, to reduce the sizes of HEAs and increase their specific surface areas, it is imperative to develop new synthetic methods for HEA preparation (Table 1). [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] Firstly, Yao et al reported a two-step carbon-thermal shock (CTS) method to prepare eight-element HEA nanoparticles (Figure 2a,b); since then, numerous scientists have begun to explore HEA nanoparticle synthesis methods. [46] Their research group then proceeded to apply this method to prepare HEAs using other element types.…”

Section: Size and Morphologymentioning

confidence: 99%

High‐Entropy Alloys for Electrocatalysis: Design, Characterization, and Applications

Zhang

Wang

2021

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electrochemical processes, including the nitrogen reduction reaction (NRR), carbon dioxide reduction reaction (CO 2 RR), oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and alcohol oxidation reaction (AOR). In the past few years, researchers have devoted themselves to developing high-performance electrocatalysts, to reduce the overpotential of the above-mentioned electrochemical reactions. [4] Currently, the most widely used and representative electrocatalysts are precious metal (e.g., Pt, Pd, Ru, Rh, Ir, Ag, and Au) alloys or their alloys with transition metals (e.g., Fe, Co, Ni, and Cu); thus, these catalysts generally comprise no more than three elements. [5] Excellent electrocatalytic performances typically require researchers to adjust and optimize the coordination environment of the electrocatalysts' surface/interface atoms and the adsorption energy of the reaction intermediates. [6] To a certain extent, the limited and simple alloy compositions prevent the development of certain special properties. Therefore, it is very important to explore unconventional alloy systems for electrocatalysis.High-entropy alloys (HEAs) are an emerging class of multicomponent alloys that have been widely employed as electrocatalysts. [7] The design concept of HEAs has already overcome the limitations of primitive alloy materials (Figure 1a). [8] HEAs provide enormous possibilities for the design of electrocatalysts (especially multifunctional electrocatalysts), owing to their variable element compositions. More importantly, the high mixing entropy (ΔG mix = ΔH mix − TΔS mix ) can result in the formation of single-phase solid solution HEA structures. [9] Clearly, a high ΔS mix can significantly lower ΔG mix and enhance the stability of the material system. [10] It is also beneficial to improve the lifetimes of electrocatalysts under severe conditions such as high temperature, strong corrosion resistance, and high electrochemical potential. [11] Since 2004, almost 5000 papers have been published regarding HEAs in various fields (e.g., magnetocaloric, anti-radiation, superconducting, thermoelectric, and catalysis materials) (Figure 1b); this is primarily attributable to their superior physical and chemical properties compared to traditional alloys (i.e., superior hardness, anti-oxidation, anti-corrosion, high strength, and wear resistance). [12] Recent studies have shown that HEAs represent excellent electrocatalytic materials for electrochemical reactions pertaining to energy storage and conversion, including NRR, CO 2 RR, OER, HER, ORR, and AOR. [13] High-entropy alloys (HEAs) are expected to function well as electrocatalytic materials, owing to their widely adjustable composition and unique physical and chemical properties. Recently, HEA catalysts are extensively studied in the field of electrocatalysis; this motivated the authors to investigate the relationship between the structure and composition of HEAs and their electrocatalytic performance. In this review, the latest...

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Autocatalytic Formation of High‐Entropy Alloy Nanoparticles

Cited by 70 publications

References 43 publications

Tailoring lattice strain in ultra-fine high-entropy alloys for active and stable methanol oxidation

Tailoring lattice strain in ultra-fine high-entropy alloys for active and stable methanol oxidation

Battery‐Driven N₂ Electrolysis Enabled by High‐Entropy Catalysts: From Theoretical Prediction to Prototype Model

High‐Entropy Alloys for Electrocatalysis: Design, Characterization, and Applications

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Autocatalytic Formation of High‐Entropy Alloy Nanoparticles

Cited by 70 publications

References 43 publications

Tailoring lattice strain in ultra-fine high-entropy alloys for active and stable methanol oxidation

Tailoring lattice strain in ultra-fine high-entropy alloys for active and stable methanol oxidation

Battery‐Driven N2 Electrolysis Enabled by High‐Entropy Catalysts: From Theoretical Prediction to Prototype Model

High‐Entropy Alloys for Electrocatalysis: Design, Characterization, and Applications

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Battery‐Driven N₂ Electrolysis Enabled by High‐Entropy Catalysts: From Theoretical Prediction to Prototype Model