Sulfonated carbon dots modified IrO2 nanosheet as durable and high-efficient electrocatalyst for boosting acidic oxygen evolution reaction

Abstract

Oxygen evolution reaction (OER) plays a crucial role in developing energy conversion and adjusting electronic structure of the electrocatalysts can effectively improve the catalytic activity and stability. However, it is a challenge to adjust the electronic structure on two-dimensional iridium dioxide nanosheets (IrO₂ NS), which have the advantages of high atom utilization. Here, we regulate the surface properties of IrO₂ NS through sulfonated carbon dots (SCDs) to promote the OER catalytic process. The catalyst IrO₂ NS/SCDs-2 exhibited excellent catalytic activity with a lower overpotential of 180 mV than IrO₂ NS (230 mV) at the current density of 10 mA·cm⁻² in a 0.5 M H₂SO₄ solution. And after 160 h of stability testing, the overpotential of IrO₂ NS/SCDs-2 only decreased by 4 mV. Moreover, transient potential scanning test can visually demonstrate that the addition of SCDs improves the conductivity of the catalyst and increases the electron transfer rate.