Perovskite With Tunable Active-Sites Oxidation State by High-Valence W for Enhanced Oxygen Evolution Reaction

Abstract

Perovskite oxides have been established as a promising kind of catalyst for alkaline oxygen evolution reactions (OER), because of their regulated non-precious metal components. However, the surface lattice is amorphous during the reaction, which gradually decreases the intrinsic activity and stability of catalysts. Herein, the precisely control tungsten atoms substituted perovskite oxides (Pr0.5Ba0.5Co1-xWxO3-δ) nanowires were developed by electrostatic spinning. The activity and Tafel slope were both dependent on the W content in a volcano-like fashion, and the optimized Pr0.5Ba0.5Co0.8W0.2O3-δ exhibits both excellent activity and superior stability compared with other reported perovskite oxides. Due to the outermost vacant orbitals of W6+, the electronic structure of cobalt sites could be efficiently optimized. Meanwhile, the stronger W-O bond could also significantly improve the stability of latticed oxide atoms to impede the generation of surface amorphous layers, which shows good application value in alkaline water splitting.

Co3O4 supported by ultrathin-layered graphitic carbon nitride for efficient electrocatalytic evolution of oxygen

“…Pt was the counter electrode and saturated glyceryl electrode (SCE) was the reference electrode. The potential value was adjusted using a reversible hydrogen electrode (RHE) using the formula: E RHE = E SCE + 0.24 + 0.0591 × pH, 28,29 where E SCE is the measurement potential of the reference electrode. The electrochemical performance of all catalysts was tested in a three-electrode system with KOH solution (1 M) as the electrolyte.…”

2D Ti3C2Tx MXene-Supported Graphitic Carbon-Nitride-Decorated Co3O4 Nanoparticles as Efficient Catalysts for Oxygen Evolution Reaction

“…To prepare the working electrodes, 20 mg of the samples was placed in a 1 mL mixture solution containing deionized water, anhydrous ethanol, and Nafion (5%) (70:30:5) and then sonicated for 30 min to ensure that the samples were completely dispersed in the mixture to form a homogeneous catalyst ink, followed by applying it uniformly on carbon paper and drying it in a vacuum oven at 60 °C as the working electrode. Pt was used as the counter electrode, and the saturated calomel electrode (SCE) was used as the reference electrode, using a reversible hydrogen electrode (RHE) adjusted potential value according to the formula: E RHE = E SCE + 0.24 + 0.0591 × pH, 39 where E SCE is the measured potential referring to the SCE reference electrode. The catalyst was tested for OER catalytic performance by linear scanning voltammetry (LSV) over a voltage range of 0.9−2.0 V vs RHE at a scan rate of 5 mV/s.…”