Synthesis of highly conductive titanium suboxide support materials with superior electrochemical durability for proton exchange membrane fuel cells

Abstract

The carbon material mainly used as a support material in proton exchange membrane fuel cells (PEMFCs) has a critical limitation—the corrosion reaction of carbon by a water-electrolysis reaction during PEMFC operation. To overcome this corrosion problem, transition metal oxides have recently been proposed as a next-generation support material to replace carbon materials. However, the low electrical conductivity of transition metal oxides leads to a negative effect on the electrochemical performance of PEMFCs. Therefore, in this study, titanium suboxide (TSO) with a crystalline phase of reduced transition metal oxide and high electrical conductivity was synthesized using a combined catalytic and thermal reduction reaction. In particular, the TSO material synthesized at a temperature of 900 °C was confirmed to exhibit a single Ti4O7 phase and electrical conductivity 105–106 times higher than that of bare TiO2. Furthermore, TSO exhibits superior electrochemical durability against corrosion reaction via a water-electrolysis reaction during PEMFC operation.