@article{
author = "Krstajić Pajić, Mila N. and Dobrota, Ana S. and Mazare, Anca and Đurđić, Slađana and Hwang, Imgon and Skorodumova, Natalia V. and Manojlović, Dragan and Vasilic, Rastko and Pašti, Igor A. and Schmuki, Patrik and Lačnjevac, Uroš",
year = "2023",
abstract = "Efficient cathodes for the hydrogen evolution reaction (HER) in acidic
water electrolysis rely on the use of expensive platinum group metals (PGMs). However, to
achieve economically viable operation, both the content of PGMs must be reduced and
their intrinsically strong H adsorption mitigated. Herein, we show that the surface effects of
hydrogenated TiO2 nanotube (TNT) arrays can make osmium, a so far less-explored PGM,
a highly active HER electrocatalyst. These defect-rich TiO2 nanostructures provide an
interactive scaffold for the galvanic deposition of Os particles with modulated adsorption
properties. Through systematic investigations, we identify the synthesis conditions (OsCl3
concentration/temperature/reaction time) that yield a progressive improvement in Os
deposition rate and mass loading, thereby decreasing the HER overpotential. At the same
time, the Os particles deposited by this procedure remain mainly sub-nanometric and
entirely cover the inner tube walls. An optimally balanced Os@TNT composite prepared at
3 mM/55 °C/30 min exhibits a record low overpotential (η) of 61 mV at a current density
of 100 mA cm−2, a high mass activity of 20.8 A mgOs
−1 at 80 mV, and a stable performance in an acidic medium. Density functional
theory calculations indicate the existence of strong interactions between the hydrogenated TiO2 surface and small Os clusters, which
may weaken the Os−H* binding strength and thus boost the intrinsic HER activity of Os centers. The results presented in this study
offer new directions for the fabrication of cost-effective PGM-based catalysts and a better understanding of the synergistic electronic
interactions at the PGM|TiO2 interface.",
publisher = "American Chemical Society",
journal = "ACS Applied Materials and Interfaces",
title = "Activation of Osmium by the Surface Effects of Hydrogenated TiO2 Nanotube Arrays for Enhanced Hydrogen Evolution Reaction Performance",
pages = "31469-31459",
number = "26",
volume = "15",
doi = "10.1021/acsami.3c04498"
}