Low-iridium doped single-crystalline hydrogenated titanates (H2Ti3O7) with large exposed {100} facets for enhanced oxygen evolution reaction under acidic conditions

Development of efficient and stable electrocatalysts for oxygen evolution reaction (OER) under acidic conditions is desirable goal for commercializing proton exchange membrane (PEM) water electroyzer. Herein, we report iridium-doped hydrogenated titanate (Ir–HTO) nanobelts as a promising catalyst with a low-Ir content for the acidic OER. Addition of low-Ir (∼ 3.36 at%) into the single-crystalline HTO nanobelts with large exposed {100} facets significantly boost catalytic activity and stability for OER under acidic conditions. The Ir-HTO outperforms the commercial benchmark IrO2 catalyst; an overpotential for delivering 10 mA cm−2 current density was reduced to about 25% for the Ir-HTO. Moreover, the catalytic performance of Ir-HTO is positioned as the most efficient electrocatalyst for the acidic OER. An improved intrinsic catalytic activity and stability are also confirmed for the Ir-HTO through in-depth electrochemical characterizations. Therefore, our results suggest that low-Ir doped single-crystalline HTO nanobelts can be a promising catalyst for efficient and durable OER under acidic conditions. •We developed an Ir-doped catalyst for the acidic oxygen evolution reaction (OER).•Ir was incorporated into a H2Ti3O7 nanobelts (Ir–HTO) with large exposed {100} facets.•The single-crystalline nature of HTO increased the active sites for the OER.•The Ir-HTO nanobelts have a low Ir content (about 3–4 wt%) at the atomic scale.•The Ir-HTO nanobelts have high catalytic activity and durability for acidic OER.