Dynamic strain and switchable polarization: A pathway to enhance the oxygen evolution reaction on InSnO₂N

InSnO₂N is a novel promising material for photoelectrochemical water splitting because of its band gap in the visible range and band edges position, which straddle the redox levels of water. Moreover, this material shows a spontaneous polarization, which could give rise to a photoferroic effect, thus enhancing the power-to-hydrogen conversion efficiency. In this work, we investigate, using Density Functional Theory (DFT) calculations, the photo-electrochemical response of this material to strain. Strain can reduce the reaction overpotentials for the Oxygen Evolution Reaction (OER) to 0.45 V for a −2.5 % compressive strain on the positively polarized material and to 0.40 V for a 2.3 % tensile strain on the negatively polarized structure. When a polarization switching is combined with a dynamic change of the strain during the reaction, the OER overpotential reaches the lowest value of 0.05 V (far below the ideal case for oxides, which is 0.37 V, and what can be reached by considering only the polarization switching at a fixed strain value). This study demonstrates the potential of InSnO₂N as a catalyst for OER and highlights how surface engineering and dynamic catalysis can enhance the electro-catalytic properties of a material.