The exclusive surface and electronic effects of Ni on promoting the activity of Pt towards alkaline hydrogen oxidation

Ni modification is considered as an efficient strategy for boosting the performance of Pt towards alkaline hydrogen oxidation reaction (HOR), yet its specific role is largely undecoded. Here, ultrathin Pt nanowires (NWs) are selected as models for revealing the significance of Ni modification on HOR by precisely positioning Ni on distinct positions of Pt NWs. Ni solely influences the electronic properties of Pt and thus weakens *H adsorption when it is located in the core of PtNi alloyed NWs, leading to a moderate improvement of alkaline HOR activity. When Ni is distributed in both core and surface of PtNi alloyed NWs, Ni strongly weakens *H adsorption but strengthens *OH adsorption. On the other hand, the electronic properties of Pt are hardly influenced when Ni is deposited on the surface of Pt NWs, on which the strong *H and *OH adsorptions lead to the improved HOR activity. This work reveals the significance of Ni modification on HOR, but also promotes the fundamental researches on catalyst design for fuel cell reactions and beyond.