In Situ X-ray Absorption Spectroscopy of PtNi-Nanowire/Vulcan XC-72R under Oxygen Reduction Reaction in Alkaline Media

[Image: see text] Studying the oxygen reduction reaction (ORR) in the alkaline electrolyte has proven to promote better catalytic responses and accessibility to commercialization. Ni-nanowires (NWs) were synthesized via the solvothermal method and modified with Pt using the spontaneous galvanic displacement method to obtain PtNi-NWs. Carbon Vulcan XC-72R (V) was used as the catalyst support, and they were doped with NH(3) to obtain PtNi-NWs/V and PtNi-NWs/V–NH(3). Their electrocatalytic response for the ORR was tested and PtNi-NWs/V provided the highest specific activity with logarithmic values of 0.707 and 1.01 (mA/cm(2)(Pt)) at 0.90 and 0.85 V versus reversible hydrogen electrode (RHE), respectively. PtNi-NWs showed the highest half-wave potential (E(1/2) = 0.89 V) at 1600 rpm and 12 μg(Pt)/cm(2) in 0.1 M KOH at 25.00 ± 0.01 °C. Additionally, the catalysts followed a four-electron pathway according to the Koutecký–Levich analysis. Moreover, durability experiments demonstrated that the PtNi-NW/V performance loss was like that of commercial Pt/V along 10,000 cycles. Electrochemical ORR in situ X-ray absorption spectroscopy results showed that the Pt L(3) edge white line in the PtNi-NW catalysts changed while the electrochemical potential was lowered to negatives values, from 1.0 to 0.3 V versus RHE. The Pt/O region in the in situ Fourier transforms remained the same as the potentials were applied, suggesting an alloy formation between Pt and Ni, and Pt/Pt contracted in the presence of Ni. These results provide a better understanding of PtNi-NWs in alkaline electrolytes, suggesting that they are active catalysts for ORR and can be tuned for fuel cell studies.