Microwave sintered porous CoCrFeNiMo high entropy alloy as an efficient electrocatalyst for alkaline oxygen evolution reaction

Fabrication, Microstructure, Mechanical, and Electrochemical Properties of NiMnFeCu High Entropy Alloy from Elemental Powders

“…Hence, the comparatively better catalytic activity of S2 with 100 cycles of CV could be due to the presence of porous microstructure and the formation of nano oxide sheets during the cyclic voltammetry sweep. The combination of porosity and nano oxide layers exposed the active sites and enhanced the catalytic activity [24,25]. So, the overpotential of S2 is lower when compared to S4, but not as low as S2-CV 100 cycles because of the presence of porosity and the absence of nano oxide layers.…”

“…For instance, it has been shown by other researchers that the HEA MnFeCoNi exhibited a low overpotential value of 302 mV to reach a current density of 10 mA cm −2 with good stability for 20 h [24]. A porous HEA CoCrFeNiMo with a magnesium space holder exhibited excellent catalytic activity with an overpotential of 220 mV and attained a current density of 10 mA cm −2 with good stability for 24 h [25]. Hence HEAs could be considered as a cheaper alternative to a rare earth-metal catalyst.…”

Bibliometric Mapping of Literature on High-Entropy/Multicomponent Alloys and Systematic Review of Emerging Applications

“…In this regard, HEA/MCAs have been developed from low-cost, non-noble metals, such as Al, Co, Fe, Cu, Zn, Cr, etc., [34,130,132], while others contain more expensive noble or platinum-group metals, such as platinum, palladium, and iridium [34,126,129]. Examples of the different catalytic applications investigated thus far include water splitting (together with hydrogen and oxygen evolution reactions) [6,126,127,132,133], methanol oxidation [134], degradation of azo dyes [128], carbon dioxide/carbon monoxide reduction reactions [129], and hydrogenation of p-nitrophenol [130].…”

“…For instance, the propensity for the formation of an intermetallic compound is favored when the solvent and solute atoms have different atomic sizes, valence, and electronegativity, according to the classical Hume-Rothery rules [2,3]. In the past few years, solid-solution alloys with simple crystal structures from multi-principal metallic components (≥5) in near-equimolar or equimolar ratios have been reported [1,[4][5][6]. It is proposed that the contribution of high mixing configurational entropy to the total free energy of the alloy can stabilize simple, solid-solution phases and suppress the formation of complex, intermetallic compounds [4,7].…”

“…This has largely been spurred by the opportunity to explore new alloy compositions that transcend the scope of traditional alloy compositions, as well as the potential to investigate interesting new advanced applications. Besides, various research directions have been explored, including investigating the formation of simple crystalline phases, with the different number of principal elements (e.g., vanadium (V), hafnium (Hf), chromium (Cr), manganese (Mn), iron (Fe), copper (Cu), and nickel (Ni)), ranging from five to as many as twenty [1,2,5,6,[14][15][16]. Similarly, researchers have utilized low-density metals, such as magnesium (Mg), aluminum (Al), lithium (Li), silicon (Si), titanium (Ti), and zinc (Zn), to develop lightweight structural HEA materials [17,18] for potential applications in the aerospace and transportation industries.…”