General Synthesis of Composition‐Tunable High‐Entropy Amorphous Oxides Toward High Efficiency Oxygen Evolution Reaction

Abstract

High‐entropy materials have attracted much attention in the electrocatalysis field due to their unique structure, high chemical activity, and compositional tunability. However, the harsh and complex synthetic methods limit the application of such materials. Herein, a universal non‐equilibrium liquid‐phase synthesis strategy is reported to prepare high‐entropy amorphous oxide nanoparticles (HEAO‐NPs), and the composition of HEAO‐NPs can be precisely controlled from tri‐ to ten‐component. The non‐equilibrium synthesis environment provided by an excessively strong reducing agent overcomes the difference in the reduction potentials of various metal ions, resulting in the formation of HEAO‐NPs with a nearly equimolar ratio. The oxygen evolution reaction (OER) performance of HEAO‐NPs is further improved by adjusting the composition and optimizing the electronic structure. The Fe16Co32Ni32Mn10Cu10BOy exhibits a smaller overpotential (only 259 mV at 10 mA cm−2) and higher stability in OER compared with commercial RuO2. The amorphous high‐entropy structure with an optimized concentration of iron makes the binding energy of CoNi shift to a higher direction, promotes the generation of high‐valence active intermediates, and accelerates the OER kinetic process. The HEAO‐NPs have promising application potential in the field of catalysis, biology, and energy storage, and this work provides a general synthesis method for composition‐controllable high‐entropy materials.

Ultrathin Porous Pd Metallene with Amorphous/Crystalline Phase Coexitence as Electrocatalysts for the Oxygen Reduction Reaction

“…The global concept of low-carbon economy and sustainable development has greatly promoted the development of renewable energy conversion and storage systems . Water electrolysis devices, fuel cells, and metal–air batteries with high energy conversion efficiency are environmentally friendly, and are considered to be effective solutions for future renewable energy. − Because of its significance in electrochemical energy conversion and storage devices, oxygen electrocatalysis is one of the hot spots in the field of electrochemical research, as well as one of the important factors for device application. ,− In particular, the oxygen reduction reaction (ORR) plays a key role in the oxygen electrode. Since ORR is the 4-electron/proton transfer process, with high overpotential and sluggish kinetic reaction rate, it is urgent to develop high-performance catalysts to accelerate ORR kinetics, improve Faradaic efficiency and reduce energy consumption.…”

Porous high-entropy oxide nanosheets as highly-efficient electrocatalysts for water oxidation

“…22–24 The unique advantages of high-entropy composition and structure endow many tunable physicochemical properties to transition metal oxides, which is beneficial to synergistically optimize the electrical conductivity, catalytic active centers as well as the binding ability to intermediate species, and then result in higher intrinsic catalytic activity and stability. 2,25,26 In light of this, various high-entropy oxides including (CrFeCoNiMo) 3 O 4 nanosheet, (FeCoNi 2 CrMn) 3 O 4 , (Fe 0.2 Co 0.2 Ni 0.2 Cr 0.2 Mn 0.2 ) 3 O 4 and LaCr 0.2 Mn 0.2 Fe 0.2 Co 0.2 Ni 0.2 O 3− δ have been developed as electrocatalysts for OER. 27–30 The differences in OER performance of high-entropy oxides demonstrate the important role of the constituent elements in the abundant regulating range of compositions.…”