Journal Article

Dynamic Tuning of a Thin Film Electrocatalyst by Tensile Strain

van de Lagemaat, Jao, Neale, Nathan R., Svedruzic, Drazenka, Gregg, Brian. A., Ha, Mai-Anh, Benson, Eric E.

2019

Overview

We report the ability to tune the catalytic activities for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) by applying mechanical stress on a highly n-type doped rutile TiO 2 films. We demonstrate through operando electrochemical experiments that the low HER activity of TiO 2 can reversibly approach those of the state-of-the-art non-precious metal catalysts when the TiO 2 is under tensile strain. At 3% tensile strain, the HER overpotential required to generate a current density of 1 mA/cm 2 shifts anodically by 260 mV to give an onset potential of 125 mV, representing a drastic reduction in the kinetic overpotential. A similar albeit smaller cathodic shift in the OER overpotential is observed when tensile strain is applied to TiO 2 . Results suggest that significant improvements in HER and OER activities with tensile strain are due to an increase in concentration of surface active sites and a decrease in kinetic and thermodynamics barriers along the reaction pathway(s). Our results highlight that strain applied to TiO 2 by precisely controlled and incrementally increasing (i.e. dynamic ) tensile stress is an effective tool for dynamically tuning the electrocatalytic properties of HER and OER electrocatalysts relative to their activities under static conditions.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 639/301 / 639/4077 / 639/638 / Catalysts / CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS / electrocatalysis / Electrochemistry / Humanities and Social Sciences / MATERIALS SCIENCE / multidisciplinary / Physical growth / Science / Science (multidisciplinary) / Strain / tensile strain / Tensile stress / Thin films / Titanium dioxide / water splitting