Synthesis of highly active Zr oxide-based oxygen reduction electrocatalysts as PEFC cathode

摘要

In order to develop a non-precious metal cathode for PEFCs, we have tried Zr oxide based materials. To synthesize fine particles, we used oxy-zirconium phthalocyanine (ZrOPc) as a starting material. ZrOPc was placed on carbon nanotube (CNT) and treated under 0.5%O_2 + 2%H_2 - N_2 atmosphere in the temperature range, 800℃ ～ 1000℃. The slow scan voltammetry (SSV) was performed to evaluate the catalytic activity for the oxygen reduction reaction (ORR) under nitrogen and oxygen atmosphere separately in 0.1 mol dm_(-3) H_2SO_4 at 30℃. The XRD analysis of these catalysts showed Tetragonal ZrO_2. The particle size was smaller than 10 nm and covered by precipitated carbon. The maximum ORR current was 142 mA gCat/C~(-1) at 0.8 V. This value was much higher than that of partially oxidized carbonitride (Zr-CNO).