Effect of conductive substrate on the photoelectrochemical properties of Cu2O film electrodes for methyl viologen reduction

Amano, Fumiaki; Uchiyama, Akihito; Furusho, Yoshiyuki; Shintani, Ayami

doi:10.1016/j.jphotochem.2019.112254

Cited by 9 publications

(17 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, the mixed oxide layer can be coated on Ti substrates with different shapes. In PEMWE, Ti materials (mesh, felt, or sintered powder) are usually used as a current collector of the anode due to the high stability in the highly oxidative environment. , The Ti felt consisting of microfibers exhibits a three-dimensional (3D) macroporous structure with a large surface area. , Such a large surface area is beneficial to increase the electrochemically active surface area (ECSA) and the contact area between the active layer and the substrate. The porous shape further may improve the mass transport and mitigate the ohmic drop caused by the gas bubble formation on the surface.…”

Section: Introductionmentioning

confidence: 99%

“…4,5 The Ti felt consisting of microfibers exhibits a three-dimensional (3D) macroporous structure with a large surface area. 26,27 Such a large surface area is beneficial to increase the electrochemically active surface area (ECSA) and the contact area between the active layer and the substrate. The porous shape further may improve the mass transport and mitigate the ohmic drop caused by the gas bubble formation on the surface.…”

Section: Introductionmentioning

confidence: 99%

“…11,28 In this study, we used the Ti microfiber felt with a large surface area for the substrate of the IrO 2 -Ta 2 O 5 layer instead of the conventional Ti plate with a flat and dense structure (Figure S1). The specific surface area of the Ti felt composed of prismatic microfibers is 444 cm 2 g −1 , 26,27 which is calculated from the diameter of the prism (20 μm) and the density of Ti (4.506 g cm −3 ). On the other hand, the specific surface area of the Ti plate with a thickness of 0.2 mm is only 23 cm 2 g −1 , which is 19 times lower than that of the Ti felt.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Amano

Furusho

Hwang

2020

ACS Appl. Energy Mater.

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Amano

Furusho

Hwang

2020

ACS Appl. Energy Mater.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Conductive Ti felt (fiber equivalent diameter: 20 μm, thickness: 0.1 mm, and porosity: 66.7%) and Ti plate (thickness: 0.2 mm) substrates were obtained from Nikko Techno and Nilaco, respectively. The areal density of the Ti felt was about 15 mg cm geo –2 , and its specific surface area was 444 cm 2 g –1 . The roughness factor, which is the ratio of the actual surface area to the apparent surface area (cm 2 cm geo –2 ), was 6.7.…”

Section: Methodsmentioning

confidence: 99%

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

et al. 2022

Self Cite

View full text Add to dashboard Cite

A mixed layer of IrO2 and Ta2O5 deposited on a Ti substrate is an effective electrode for the catalysis of oxygen evolution reactions (OERs) in acidic solutions. In our previous work, IrO2–Ta2O5 catalysts supported on Ti fibers exhibited an amorphous structure, a large electrochemically active surface area (ECSA), and a high stability in acidic media. However, the local structure of amorphous OER electrocatalysts has not been studied extensively. In this study, the properties of an amorphous IrO2–Ta2O5 layer were analyzed through X-ray absorption spectroscopy (XAS) to understand the factors that contribute to its high OER stability. Herein, the addition of polyethylene glycol (PEG) to a precursor composed of H2IrCl6 and TaCl5 resulted in the formation of IrO2 nanoparticles with low chlorine residues even after thermal decomposition at a low temperature of 350 °C. X-ray diffraction and Raman spectroscopy results showed that the synthesized IrO2 nanoparticles were amorphous. However, from the XAS results, the local [IrO6] octahedron structure, which is similar to that of rutile IrO2 crystals, was revealed. During the preparation process, PEG assisted a complete ligand exchange from the [IrCl6] octahedron to the [IrO6] octahedron. This local structure of the IrO2 nanoparticles makes the amorphous IrO2–Ta2O5 layer on the Ti fibers stable during OER in acidic media. Furthermore, sintering is unlikely to occur during the synthesis because of the low thermal decomposition temperature of the precursor. As such, the synthesized amorphous IrO2 nanoparticles exhibited a large ECSA. In addition, the high intrinsic activity of the [IrO6] local structure resulted in a small Tafel slope. Thus, the amorphous IrO2 nanoparticles with an [IrO6] local structure are essential not only to achieve high activity but also high stability during the OER.

show abstract

“…17 Large surface area of the substrate is beneficial in increasing the ECSA and the contact area between the electrocatalytic and the substrate layers. 18,19 High-temperature calcination usually forms rutile-type IrO 2 crystallites, 20 but the IrO 2 coated on Ti felt was amorphous even after calcination at 650°C. 17 Amorphous IrO 2 has been reported to exhibit high OER activity compared to crystalline IrO 2 .…”

Section: Introductionmentioning

confidence: 99%

Effect of Adding Polyethylene Glycol to the Precursor Solution of Amorphous IrO2-Ta2O5 Electrocatalysts for Oxygen Evolution Reaction

Furusho

Amano

2021

Electrochemistry

Self Cite

View full text Add to dashboard Cite

Amorphous IrO 2 -Ta 2 O 5 electrocatalyst 2H 2 O O 2 + 4H + 100 nm 50 μm Activity DurabilityWe report amorphous iridium oxide (IrO 2 ) and tantalum oxide (Ta 2 O 5 ) electrocatalysts supported on titanium fiber felt as effective anodes for oxygen evolution reaction (OER). The IrO 2 -Ta 2 O 5 electrode, prepared by thermal decomposition of the precursor added with polyethylene glycol (PEG), achieved a current density of 10 mA cm −2 at a low overpotential of 0.24 V in a sulfuric acidic solution. The high OER activity is because PEG generated mesopores in the amorphous IrO 2 -Ta 2 O 5 layer after heating at 350°C. The increase in the double-layer capacitance, proportional to the electrochemically active surface area (ECSA), was responsible for the high current density at low overpotentials. Furthermore, the addition of the polymer to the precursor suppressed the dissolution of Ir from the anode during the OER stability test and improved the durability of the IrO 2 -Ta 2 O 5 electrocatalyst coated on the Ti felt.

show abstract

Effect of conductive substrate on the photoelectrochemical properties of Cu2O film electrodes for methyl viologen reduction

Cited by 9 publications

References 32 publications

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

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

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

Effect of Adding Polyethylene Glycol to the Precursor Solution of Amorphous IrO<sub>2</sub>-Ta<sub>2</sub>O<sub>5</sub> Electrocatalysts for Oxygen Evolution Reaction

Contact Info

Product

Resources

About

Effect of conductive substrate on the photoelectrochemical properties of Cu2O film electrodes for methyl viologen reduction

Cited by 9 publications

References 32 publications

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

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

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

Effect of Adding Polyethylene Glycol to the Precursor Solution of Amorphous IrO<sub>2</sub>-Ta<sub>2</sub>O<sub>5</sub> Electrocatalysts for Oxygen Evolution Reaction

Contact Info

Product

Resources

About

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