Amorphous Iridium and Tantalum Oxide Layers Coated on Titanium Felt for Electrocatalytic Oxygen Evolution Reaction

Abstract

The layer of electrocatalytic mixed oxides is known as a dimensionally stable anode (DSA) used in many industrial electrochemical processes. A layer of iridium oxide (IrO2) and tantalum oxide (Ta2O5) coated on a titanium (Ti) substrate electrode is active for oxygen evolution reaction (OER) in acidic solution. Herein, we used a porous Ti felt composed of microfibers as a conductive substrate for the IrO2-Ta2O5 electrocatalytic layer. The effect of the Ti substrates and the calcination temperature on the electrocatalytic activity for OER was investigated by cyclic voltammetry in an acidic sulfate solution. The results show that the IrO2-Ta2O5 layer on the porous Ti felt with a large surface area was more active than the layer on the conventional Ti plate. The electrocatalytic activity of IrO2-Ta2O5 layers was maximized by calcination at 350 °C and decreased by increasing the calcination temperature with the decrease of the double-layer capacitance (C dl), which is recognized as an electrochemically active surface area (ECSA). The IrO2-Ta2O5 thin layer on the Ti felt was amorphous in the measurement of X-ray diffraction and Raman spectroscopy. The amorphous layer was confirmed to have rare cracks, larger ECSA, and higher catalytic activity for OER. The overpotential required to reach the current density of 10 mA cm–2 was only 0.27 V. The constant current was the Faradaic current for water oxidation to evolve O2.

Accelerating Bubble Detachment in Porous Transport Layers with Patterned Through-Pores

“…However, mass transport losses must first be minimized in order to facilitate high current density operation. While extensive research has been conducted for designing the catalyst layer − and membrane to advance electrolyzer performance, the strategic design of porous transport layers (PTLs) for high current density operation ( i > 5 A/cm 2 ) has been largely overlooked in the field.…”

Structure–Stability Relationship of Amorphous IrO2–Ta2O5 Electrocatalysts on Ti Felt for Oxygen Evolution in Sulfuric Acid

“…The titanium substrates were cut to a size of 1.0 × 2.5 cm 2 , washed with acetone and deionized water, and masked with Teflon tape to expose an area of 1.0 cm 2 . The IrO 2 –Ta 2 O 5 layer (Ir/Ta mole ratio = 70:30) was deposited on the Ti substrates through drop-casting. , The precursor solution (10 μL) was dropped onto the apertural area and dried at 80 °C for 5 min. This procedure was repeated three times.…”

Boosting the oxygen evolution stability and activity of a heterogeneous IrRu bimetallic coating on a WO3 nano-array electrode for PEM water electrolysis

“…[21][22][23] When it comes to the electrode, catalyst-coated membranes (CCMs) is comprehensively effected by catalyst activity, catalyst layer structure and electrolyte membrane. The use of a nanostructured electrode with ordered mass-delivery channels and a three-phase interface is an effective strategy, and it can be based on nanobers, 24 nanoarrays, 25 and so on. 26 Issues hindering the application of nanostructured electrodes in PEM water electrolysis include difficulties obtaining both chemically stable and conductive electrodes and ensuring the good distribution of the catalyst on the electrode surface.…”