Synthesis of PtAu/TiO2 nanowires with carbon skin as highly active and highly stable electrocatalyst for oxygen reduction reaction

To enhance the activity and durability of platinum (Pt) or platinum-based catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs), fabrication of low-cost platinum catalysts with durable structure is necessary. Here, a series of one-dimensional (1D) platinum-gold/titanium dioxide nanowires (PtAu/TiO 2 NWs) catalysts with different Pt/Au/Ti ratios were synthesized by electrospinning, and the microstructure as well as its electrochemical properties for ORR were investigated. The results illustrate that PtAu/TiO 2 NWs indicate a parabolic-type ORR performance as a function of compositions . The optimized Pt 1 Au 1 /(TiO 2 ) 1 NWs exhibited 4.19 times in mass activity and 2.82 times in SA when compared with commercial Pt on carbon catalyst (20% Pt/C). In addition, the stability test shows that the ECSA of Pt 1 Au 1/ (TiO 2 ) 1 NWs present almost 20% decrease, while the 20%Pt/C drops more than 40% at the same condition. The extraordinary activity of Pt 1 Au 1/ (TiO 2 ) 1 NWs could be attributed to the synergistic effect of TiO 2 and the durability attributed to Au and C skin. The nanowires with larger specific area show that the Pt electronic structure can be changed by the neighbouring TiO 2 , further decreasing the d-band gap to enhance catalytic activity.