Premium
Tweaking Nickel with Minimal Silver in a Heterogeneous Alloy of Decahedral Geometry to Deliver Platinum‐like Hydrogen Evolution Activity
Author(s) -
Majee Rahul,
Kumar Arun,
Das Tisita,
Chakraborty Sudip,
Bhattacharyya Sayan
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201913704
Subject(s) - nickel , catalysis , alloy , materials science , platinum , overpotential , atom (system on chip) , crystallography , chemistry , metallurgy , electrochemistry , electrode , computer science , embedded system , biochemistry
Five‐fold intertwined Ag x Ni 1− x ( x =0.01–0.25) heterogeneous alloy nanocrystal (NC) catalysts, prepared through unique reagent combinations, are presented. With only ca. 5 at % Ag (AgNi‐5), Pt‐like activity has been achieved at pH 14. To reach a current density of 10 mA cm −2 the extremely stable AgNi‐5 requires an overpotential of 24.0±1.2 mV as compared to 20.1±0.8 mV for 20 % Pt/C, both with equal catalyst loading of 1.32 mg cm −2 . The turnover frequency (TOF) is as high as 2.1 H 2 s −1 at 50 mV (vs. RHE). Site‐specific elemental analyses show the Ag:Ni compositional variation, where the apex and edges of the decahedra are Ag‐rich, thereby exposing Ni onto the faces to achieve maximum charge transport for an exceptional pH universal HER activity. DFT calculations elucidate the relative H‐atom adsorption capability of the Ni centers as a function of their proximity to Ag atom.