Oxygen reduction reaction on electrochemically deposited sub-monolayers and ultra-thin layers of Pt on (Nb-Ti)2AlC substrate

Catalytic activity towards the oxygen reduction reaction (ORR) in 0.5 M H2SO4 was investigated at sub-monolayers and ultra-thin layers (corresponding to 10, 30 100 monolayers, (MLs)) of Pt electrochemically deposited on (Nb-Ti)2AlC substrate. Electrochemical deposition substrate achieved from solution containing 3 mM K2PtCl4 + NaCl (pH 4) under conditions convective diffusion (RPM = 400) using linear sweep voltammetry (LSV) a rate 2 mV s-1 , by determining limiting potential for each sample QPt vs. E curves. The samples were characterized X-ray photoelectron spectroscopy (XPS). XPS analysis showed that practically whole surface is covered with homogeneous layer Pt, while ion complete metallic form - Pt(0) valence state. Then studied rotating disc electrode cyclic voltammetry. Two different Tafel slopes observed, one close 60 dec-1 low current densities region second ~ 120 high region. This novel catalyst exhibited higher comparison carbon supported one, terms mass kinetic density normalized loading.