A New High Entropy Glycerate for High Performance Oxygen Evolution Reaction

Abstract

Herein, a new high entropy material is reported, i.e., a noble metal‐free high entropy glycerate (HEG), synthesized via a simple solvothermal process. The HEG consists of 5 different metals of Fe, Ni, Co, Cr, and Mn. The unique glycerate structure exhibits an excellent oxygen evolution reaction (OER) activity with a low overpotential of 229 and 278 mV at current densities of 10 and 100 mA cm−2, respectively, in 1 m KOH electrolyte, outperforming its subsystems of binary‐, ternary‐, and quaternary‐metal glycerates. The HEG also shows outstanding stability and durability in the alkaline electrolyte. The result demonstrates the significance of synergistic effect that gives additional freedoms to modify the electronic structure and coordination environment. Moreover, HEG@HEG electrolyzer shows a good overall water splitting performance and durability, requiring a cell voltage of 1.63 V to achieve a current density of 10 mA cm−2.

Self‐Reconstruction of Sulfate‐Containing High Entropy Sulfide for Exceptionally High‐Performance Oxygen Evolution Reaction Electrocatalyst

“…At overpotential of 270 mV, the FeNiCoCrMnS 2 delivers a current density of 335 mA cm -2 , outperforming of many reported transition metal chalcogenides, transition metal chalcogenides's derivatives, and other HEMs catalysts (Figure 3b and Table S2, Supporting Information). [11,12,15,16,19,20,[32][33][34][35][36] Furthermore, to yield an even higher current density of 1000 mA cm -2 , the FeNiCoCrMnS 2 only requires overpotential of 308 mV, comparable to many recently reported nonprecious, state-of-the-art catalysts, such as S-(Ni,Fe)OOH (≈350 mV), [19] (Ni,Fe)OOH (289 mV), [37] NiFe-LDH/Cu (315 mV). [38] At 100 mA cm -2 , the FeNiCoCrMnS 2 shows 13, 24, 26, and 51 mV of overpotential improvements over the FeNiCoCrS 2 , FeNiCoS x , FeNiS x , and FeS x , respectively.…”

“…Materials Synthesis: High entropy glycerate templates were first synthesized using a facile solvothermal process as reported previously. [35] In brief, equimolar metal nitrates of (Fe(NO 3 ) 3 •9H 2 O, Ni(NO 3 ) 3 •6H 2 O, Co(NO 3 ) 2 .6H 2 O, Cr(NO 3 ) 2 .9H 2 O, and Mn(NO 3 ) 2 .6H 2 O (0.5 mmol each) were dissolved in 34 mL isopropanol, followed by the addition 6 mL of glycerol. Homogeneously mixed solution was transferred to a 100 mL Teflon-lined stainless-steel autoclave for solvothermal reaction at 150 °C for 10 h. The resulting powders were collected and used as the templates for the metal sulfides synthesis.…”

“…The M-O signal then increases with the reaction time and becomes equal to that of the OH -, indicating the formation of (oxy)hydroxide. [17,35,37] The XPS data depicts that the FeNiCoCrMnS 2 converts to MOOH in situ during the OER, with some sulfate left in the structure. This again supports the aforementioned statement that the co-existence of MOOH (or M 3+ ) and SO 42is favorable for OER activity.…”

Advanced High Entropy Perovskite Oxide Electrocatalyst for Oxygen Evolution Reaction

“…The presence of Cr has been shown to increase OER activity in various materials. [ 46–48 ] A partial oxidation of Cr 3+ to Cr 6+ improves the OER activity. [ 49,50 ] Also, Mn 3+ cations are often regarded as the active species, with the existence of Mn 4+ critically affecting the catalytic activity in a manner that a synergistic effect of Mn 3+ and Mn 4+ ions was found to enhance the electrocatalytic performance in OER reactions.…”

Tailoring the Electrocatalytic Activity of Pentlandite FexNi9‐XS8 Nanoparticles via Variation of the Fe : Ni Ratio for Enhanced Water Oxidation

“…[4][5][6] Consequently, intensive research has been conducted to design cost-effective, efficient, stable, and earthabundant electrocatalysts to bring these energy technologies to cost parity. Currently, non-noble transition metal catalysts including layered double hydroxides LDH (e. g. FeNi LDH), [7] metal oxides (e. g. Co 3 O 4 ), [8][9][10][11][12][13] perovskites (e. g. LaSrFeO 3 ) [14,15] and high entropy materials (e. g. multi-metallic glycerate) [16,17] are reported as the most active non-precious OER catalysts in alkaline environment. In particular, the NiFe (oxy)hydroxide has revealed outstanding OER activity and stability.…”