A doped metal oxide PGM-free electrocatalyst for the oxygen reduction reaction

A non-carbonaceous electrocatalyst free of platinum group metals (PGM-free) was developed based on dual doped titanium suboxide. Specifically, Ti4O7Ni0.15Cu0.22 (TONC) was prepared by dual doping titanium dioxide with Cu and Ni. Density functional theory (DFT) computations confirms that the unique combination of dopant and Ti suboxide in TONC creates a low band-gap material with high electrical conductivity. The resultant dual-doped Ti suboxide shows significant electrocatalytic activity for the oxygen reduction reaction (ORR) in alkaline media, reducing the performance gap between PGM-free electrocatalysts and Pt/C to ca. 18 mV in RDE testing. Furthermore, TONC displays vastly superior electrochemical durability compared to both Pt/C and other carbon-based PGM-free catalysts. TONC showed lower ORR activity in acidic media compared to Pt/C but TONC had superior durability. Thus TONC has is a both a promising catalyst and catalyst support material for either anion-exchange membrane (AEM) or proton exchange membrane fuel cells.