Continuous Synthesis of Hollow High‐Entropy Nanoparticles for Energy and Catalysis Applications

Abstract

Mixing multimetallic elements in hollow‐structured nanoparticles is a promising strategy for the synthesis of highly efficient and cost‐effective catalysts. However, the synthesis of multimetallic hollow nanoparticles is limited to two or three elements due to the difficulties in morphology control under the harsh alloying conditions. Herein, the rapid and continuous synthesis of hollow high‐entropy‐alloy (HEA) nanoparticles using a continuous “droplet‐to‐particle” method is reported. The formation of these hollow HEA nanoparticles is enabled through the decomposition of a gas‐blowing agent in which a large amount of gas is produced in situ to “puff” the droplet during heating, followed by decomposition of the metal salt precursors and nucleation/growth of multimetallic particles. The high active sites per mass ratio of such hollow HEA nanoparticles makes them promising candidates for energy and electrocatalysis applications. As a proof‐of‐concept, it is demonstrated that these materials can be applied as the cathode catalyst for Li–O2 battery operations with a record‐high current density per catalyst mass loading of 2000 mA gcat.−1, as well as good stability and durable catalytic activity. This work offers a viable strategy for the continuous manufacturing of hollow HEA nanomaterials that can find broad applications in energy and catalysis.

Laser-generated high entropy metallic glass nanoparticles as bifunctional electrocatalysts

“…However, at the 2 nd IP or in other words, the 2 nd set of active sites at about 0.4 V higher overpotential (compared to the 1 st IP), the CrCoFeNiMn cantor HEMG NPs outperform the other compositions as also visible from the corresponding LSV curves at lower potentials with higher negative current density values. Accordingly, also the Cr 16 S8(b) in the ESM). Even though more IPs from other less active sites could be extracted, it is not feasible due to the higher overpotentials.…”

“…Nonetheless, we will use the expression HEA throughout this manuscript as it is deeply rooted in the discourse. It is well established that a rational design of HEA composition allows controlling their physicochemical properties at the nanoscale and performance, e.g., in catalysis [12,15,16] and energy storage [17][18][19]. Due to these unique interactions of distinct neighboring metal atoms [2], HEA NPs are discussed and developed as very promising candidates to replace established but scarce and expensive noble metals in catalytic reactions such as oxygen evolution [20][21][22][23][24], oxygen reduction [2,25,26], methanol oxidation [27][28][29], CO 2 reduction [30,31] and hydrogen evolution [22,32,33].…”

High-entropy materials for catalysis: A new frontier

“…Carbothermal shock synthesis of HEA nanoparticles manifests the accessibility of single-phase HEA nanoparticles with intriguing catalytic properties. The following synthetic work extended to a portfolio of nanoscale HEA architectures ranging from aerosols to hollow nanoparticles (61)(62)(63). However, fabrication of multielemental alloy (MEA) nanoparticles remains unpredictable because of the innumerable elemental combinations.…”

Spontaneously Forming Oxide Layer of High Entropy Alloy Nanoparticles Deposited on Porous Carbons for Supercapacitors

“…Recently, the concept of high entropy alloys (HEAs) had been extended and researched in energy conversion and storage, such as electrocatalyst for hydrogen evolution reaction, an anchor of polysulfide for lithium‐sulfur batteries, and electrode materials for supercapacitors [25–31] . Specially, the applications of HEAs in supercapacitors exhibited a superior capacitive performance.…”

“…[24] Recently, the concept of high entropy alloys (HEAs) had been extended and researched in energy conversion and storage, such as electrocatalyst for hydrogen evolution reaction, an anchor of polysulfide for lithium-sulfur batteries, and electrode materials for supercapacitors. [25][26][27][28][29][30][31] Specially, the applications of HEAs in supercapacitors exhibited a superior capacitive performance. For instance, Jin et al [29] prepared a new class of high entropy metal nitrides functioned as a promising candidate for electrochemical supercapacitor, with a specific capacitance of 230 F/g at a scan rate of 10 mV/s.…”