Doped TiO2 supported-Catalysts for Oxygen Evolution Reaction in Polymer Electrolyte Membrane Electrolytic Cell

Tuesday, 30 May 2017
Grand Ballroom (Hilton New Orleans Riverside)
E. J. Kim, M. Kim, and E. Cho (Korea Advanced Institute of Science and Technology)
Polymer electrolyte membrane electrolytic cells (PEMECs) is one of appropriate energy storage systems connected with renewable energy due to high drive current and endurance under road fluctuation. In water electrolysis, oxygen evolution reaction (OER) occurs under acidic and high potential. So, the large amount of precious metal catalyst is needed for performance and stability. Introduction of supporting materials could reduce the amount of precious metal catalyst without performance degradation. Titanium oxide (TiO2) is one of few materials which shows good stability under acidic and high potential conditions. Also low electronic conductivity of TiO2 (~10-6 S/cm) can overcome with introduction of appropriate doping element into TiO2.

In this work, various metal elements were doped into TiO2 supporting materials. M-doped TiO2 were prepared by electrospinning method. Figure 1 (a) is a SEM image of prepared nanofiber TiO2. M-doped TiO2 were characterized to study physical and chemical properties. Then, iridium catalysts on M-doped TiO2 support (Ir/M-doped TiO2) were synthesized by polyol method and were electrochemically evaluated. OER activity of prepared catalysts was measured by linear sweep voltammetry in oxygen-saturated 0.5 M H2SO4, respectively. As shown in fig. 1 (b), polarization curves for each catalysts were changed as variation of doping elements. Ir/M-doped TiO2 shows higher OER activity than iridium black. From these results, it was obtained that introduction of dopant into TiO2 change the characteristics of TiO2 and this change contribute to improvement OER activity. Ir/M-doped TiO2could be suggested OER catalyst to reduce the amount of precious metal catalyst without performance degradation.

Fig 1. (a) SEM images of electrospun TiO2 nanofiber, (b) Polarization curves of prepared catalysts and commercial Ir black measured in O2-saturated 0.5 M H2SO4 solution at room temperature with rotation speed of 1600 rpm and scan rate of 2 mV/sec