Platinum-Group-Metal High-Entropy-Alloy Nanoparticles

Abstract

The platinum-group metals (PGMs) are six neighboring elements in the periodic table of the elements. Each PGM can efficiently promote unique reactions, and therefore, alloying PGMs would create ideal catalysts for complex or multistep reactions that involve several reactants and intermediates. Thus, high-entropy-alloy (HEA) nanoparticles (NPs) of all six PGMs (denoted as PGM-HEA) having a great variety of adsorption sites on their surfaces could be ideal candidates to catalyze complex reactions. Here, we report for the first time PGM-HEA and demonstrate that PGM-HEA efficiently promotes the ethanol oxidation reaction (EOR) with complex 12-electron/12-proton transfer processes. PGM-HEA shows 2.5 (3.2), 6.1 (9.7), and 12.8 (3.4) times higher activity than the commercial Pd/C, Pd black and Pt/C catalysts in terms of intrinsic (mass) activity, respectively. Remarkably, it records more than 1.5 times higher mass activity than the most active catalyst to date. Our findings pave the way for promoting complex or multistep reactions that are seldom realized by mono- or bimetallic catalysts.

On the electronic structure and hydrogen evolution reaction activity of platinum group metal-based high-entropy-alloy nanoparticles

“…29 To understand the very high HER performance of IrPdPtRhRu HEA NPs, the TOF values at 50 mV were plotted as a function of experimental d-band centre (set Fermi level at zero binding energy) because the metal-H binding of monometallic and most binary catalysts can be inferred from the d-band centre. 11 When the d-band centre moves to lower energy, the metal-H bonding becomes weaker and thus HER activity increases. As shown in Fig.…”

“…10 We have found that IrOsPtPdRhRu could catalyse ethanol oxidation with a 12-electron process, although the single metals generally prompt a four-electron process at most. 11 Löffler et al found that Cr-Mn-Fe-Co-Ni complex solid solution showed at least comparable catalytic activity to Pt in oxygen reduction reaction (ORR), in despite that none of its constituents had good ORR activity. 12 In addition to HEA, other alternative denominations have also been discussed elsewhere, such as complex solid solutions, [12][13][14] multiprincipal element alloys, 15 polyelemental particles, 16,17 multi-elemental alloy, 18 and multimetallic clusters/particles.…”

“…19 These kinds of alloys may present a class of promising ideal catalysts having desired activity, stability and selectivity and thus make a paradigm shi in catalysis research. 20 These alloy catalysts with appealing performances have been reported recently, [10][11][12][17][18][19][21][22][23][24] yet, the interpretation on their properties is still challenging. Quite recently, Rossmeisl and co-authors have made a great step in theoretically predicting ORR 25 and CO 2 and CO reduction 26 properties on HEAs by combing density functional theory calculations and supervised machine learning.…”

A Tensile‐Strained Pt–Rh Single‐Atom Alloy Remarkably Boosts Ethanol Oxidation

“…As shown in Table S1 in the Supporting Information, PtBi@PtRh 1 nanoplates exhibit a high electrocatalytic performance toward EOR in alkaline electrolyte, outperforming current state-of-theart high-performance electrocatalysts. [2,15,42,[56][57][58][59] It should be noted that, although such unique tensile-strained SAA nanoplates are not directly achieved by a wet-chemical co-deposition method, it is already possible to scale up the synthesis of this nanostructured catalyst to ≈200 mg per batch (Figure S40, the Supporting Information).…”

Hydrogen Spillover-Driven Low Temperature Synthesis of High-Entropy Alloy Nanoparticles as a Robust Catalyst

“…11 In an early study, Yao et al succeeded in the fabrication of HEA NPs containing up to eight elements on conductive carbon nano bers, using a carbothermal shock method based on ash heating (at approximately 10 5 K/s) to approximately 2000 K followed by rapid cooling (at the same approximate rate). [12][13][14] Subsequently, methods incorporating ultrasonication, 15 solvothermal synthesis, 16 polyols in solution 17,18 and fast moving bed pyrolysis 19 were explored as alternative synthetic approaches. Unfortunately, these methods still require the application of high temperatures and special experimental apparatuses.…”