Amorphous/Crystalline Heterostructured Cobalt‐Vanadium‐Iron (Oxy)hydroxides for Highly Efficient Oxygen Evolution Reaction

Abstract

The oxygen evolution reaction (OER) is a key process involved in energy and environment‐related technologies. An ideal OER electrocatalyst should show high exposure of active sites and optimal adsorption energies of oxygenated species. However, earth‐abundant transition‐metal‐based OER electrocatalysts still operate with sluggish OER kinetics. Here, a cation‐exchange route is reported to fabricate cobalt‐vanadium‐iron (oxy)hydroxide (CoV‐Fe0.28) nanosheets with tunable binding energies for the oxygenated intermediates. The formation of an amorphous/crystalline heterostructure in the CoV‐Fe0.28 catalyst boosts the exposure of active sites compared to their crystalline and amorphous counterparts. Furthermore, the synergetic interaction of Co, V, and Fe cations in the CoV‐Fe0.28 catalyst subtly regulates the local coordination environment and electronic structure, resulting in the optimal thermodynamic barrier for this elementary reaction step. As a result, the CoV‐Fe0.28 catalyst exhibits superior electrocatalytic activity toward the OER. A low overpotential of 215 mV is required to afford a current density of 10 mA cm−2 with a small Tafel slope of 39.1 mV dec−1, which outperforms commercial RuO2 (321 mV and 86.2 mV dec−1, respectively).

Host Modification of Layered Double Hydroxide Electrocatalyst to Boost the Thermodynamic and Kinetic Activity of Oxygen Evolution Reaction

“…Layered double hydroxides (LDHs) have been considered as the promising candidate with satisfying performance toward OER especially in alkaline water splitting, [ 16–21 ] which can be described by the general formula [M 2+ 1− x M 3+ x (OH) 2 ] x + (A n − ) x / n · y H 2 O (M 2+ and M 3+ are divalent and trivalent metals in the positively charged host layers; A n − is the interlayer anion for charge compensation). Typically, the edge‐sharing metal‐O 6 octahedral host layer has turned out to be the active center for oxygen‐evolving process.…”

A Glass‐Ceramic with Accelerated Surface Reconstruction toward the Efficient Oxygen Evolution Reaction

“…For example, amorphous RuTe 2 porous nanorods and NiFeMo oxides have been fabricated for water splitting [10, 11] . Although amorphous materials have intrinsic high activity, the low electrical conductivity severely limits their charge transfer kinetics [12] . Therefore, the development of new noble‐metal‐free electrocatalysts is vitally in demand.…”

Synergized Multimetal Oxides with Amorphous/Crystalline Heterostructure as Efficient Electrocatalysts for Lithium–Oxygen Batteries

“…[15,16,21,22] Compared with unary and binary metal oxides, trimetallic oxides, especially those featured with the introduction of a third metallic element with high valence, can achieve effectively modulated electronic structure, optimizing the adsorption energy of reaction intermediates and thereby promoting the catalytic activity. [23,24] For example, Sargent and co-workers reported that introduction of non-3d metal W with high-valence High theoretical specific energy of rechargeable lithium-oxygen (Li-O 2 ) batteries makes them very promising in the development of long driving range electric vehicles and energy storage on large-scale. However, the large polarization and poor cycling stability associated with insufficient catalytic cathodes and the insulating nature of discharge products limit their practical applications.…”