Corrosion-Resistant PEMFC Cathode Catalysts Based on a Magnéli-Phase Titanium Oxide Support Synthesized by Pulsed UV Laser Irradiation

Abstract

Nano-sized sub-stoichiometric titanium oxide (TiOx), synthesized by pulsed UV laser irradiation of TiO 2 , was used as a catalyst support material for a PEMFC cathode, and its catalytic activity for the oxygen reduction reaction (ORR) and stability against high potentials >1.0 V were examined by comparison to a conventional Pt/C catalyst. The catalyst structure and composition were determined by XRD, TEM and EDX, and the results showed that Pt particles deposited on a TiOx support are alloyed with titanium to form an ordered Pt 3 Ti phase. The catalytic activity for ORR was evaluated using the rotating disk electrode (RDE) technique in 0.1M HClO 4 at 25 C, and the results showed that Ti-alloyed Pt/TiOx catalysts exhibited 2-fold higher specific activity than conventional Pt/XC72. This enhanced activity of Pt/TiOx catalysts is believed to be due to the formation of Pt-Ti alloy. Catalyst stability at high potentials was examined by potential cycling between 1.0 and 1.5 V vs RHE in 0.1M HClO 4 at 60 C. While Pt/TiOx catalysts retained their initial electrochemical active area (ECA) after 10000 voltage cycles, Pt/XC72 lost 30-50% of its initial ECA after 10 000 cycles, which indicates that Pt/TiOx catalysts are highly stable under high potential conditions.

Activity of IrO2 supported on tantalum-doped TiO2 electrocatalyst for solid polymer electrolyte water electrolyzer

“…8,9 The high corrosion resistance and electrochemical stability demonstrated by titanium oxides even at low pH has encouraged studies of these materials in fuel cells. 10 Titania has the added advantage of being cost-effective, nontoxic, and readily available. However, because of the low electron conductivity of TiO 2 , IrO 2 supported on bare TiO 2 electrocatalyst is deemed unsuitable.…”

“…Tantalum-modied TiO 2 has previously been used as a thick lm gas sensor, nanowires for solar cells, and for varistor applications and possesses electrical conductivities of as high as 10 3 S cm À1 when synthesized as an epitaxial thin lm.…”

Oxygen Reduction Reaction Activity and Durability of Pt Catalysts Supported on Titanium Carbide

“…So far, electronic conductive oxides or nitrides have been examined as stable supports for PEFCs, e.g., Pt/SnO2 [18,19], Pt/TiO2 [20][21][22][23], Pt/Ti4O7 [24,25], Pt/TiN [26], among others. The support materials used are typically in the form of nanoparticles with HSA to disperse Pt catalyst particles uniformly, but the use of HSA supports often leads to a high contact resistance between the particles.…”

Advances in Ceramic Supports for Polymer Electrolyte Fuel Cells

“…TEM images proved that after 8000 cycles the Pt/XC-72 went through considerable Pt aggregation whereas the morphology of Pt/TSO remained intact. Ioroi et al also studied Pt/TSO-based electrodes for PEMFC [43][44][45]. Although promising, one of the most significant issues that still remains unsolved with the sub-stoichiometric titanium oxide is its relatively low surface area which translates to lower current densities.…”