Development of Electrodeposited IrO2 Electrodes and Its Catalytic Activity towards Oxygen Evolution Reaction in Polymer Electrolyte Membrane Based Water Electrolysis

Polymer electrolyte membrane based water electrolysis (PEMWE) is an environmental friendly way to produce hydrogen with largely reduced CO₂ emission [1]. However, for commercial applications, further cost reduction is highly required. Conventionally, Ir and Ru based electrocatalysts are utilized in anodes (~4 mg/cm²), and Pt based electrocatalysts in cathodes (~1 mg/cm²). In this study, electrodes were fabricated by anodic electrodeposition of IrO₂on carbon papers [2], and its catalytic activities towards oxygen evolution electrodes (anodes) were characterized.

 By anodic electrodeposition technique, IrO₂ was electrodeposited on carbon papers in a three electrode cell (Autolab, PGSTAT302N). A glassy carbon electrode and SCE were utilized as counter and reference electrodes, respectively. The deposition voltage and time were varied to control the loading amount and surface morphology. After electrodepositon, the microstructures and oxidation states of IrO₂ deposition were analyzed by field emission scanning electron microscope (FE-SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The amount of deposited IrO₂, which was determined by the inductively coupled plasma-mass spectrometry (ICP-MS), was 0.007~0.464 mg/cm² at various deposition voltages and times.

 For single cell tests, cathode electrodes were fabricated by spraying commercial Pt/C (Tanaka, 45.9 wt%) on carbon paper (Pt loading: 0.8 mg/cm²), and commercial Nafion 212 membranes were utilized as polymer electrolytes. Then, the water electrolysis performances were evaluated at 90^oC. The highest performance was observed for the electrodes with IrO₂ loading of 0.09 mg/cm². Interestingly, although the anode catalyst loading was largely decreased, the single cell performances in this study were comparable to the previous reports [3-5].

References

[1]     F. Mueller-Langer, E. Tzimas, M. Kaltschmitt, S. Peteves, Int. J. Hydrogen Energy, 32, 3797, (2007).

[2]     K. Yamanaka, Jpn. J. Appl. Phys., 28, 632, (1989).

[3]     Shidong Song, Huamin Zhang, Xiaoping Ma, Zhigang Shao, Richard T. Baker, Baolian Yi, Int. J. Hydrogen Energy, 33, 4955, (2008).

[4]     Jinbin Cheng, Huamin Zhang, Guobao Chena, Yining Zhanga, Electrochim. Acta, 54, 6250, (2009).

[5]     Lirong Ma, Sheng Sui, Yuchun Zhai, Int. J. Hydrogen Energy, 34, 678, (2009).