Carbon-quantum-dots-embedded MnO2 nanoflower as an efficient electrocatalyst for oxygen evolution in alkaline media

Abstract

Although great advances have been achieved in the field of electrocatalysis, highly active, durable, and earth-abundant electrocatalysts for oxygen production are in increasingly demand as a result of their promising application in future energy-conversion technologies. Here, the construction of a novel class of cost-efficient electrocatalysts for oxygen evolution reaction (OER), employing carbon dots (CDs), is reported. Benefitting from the successful incorporation of CDs into MnO2 nanoflowers, the resultant CDs-MnO2 with high surface areas, enhanced conductivity, as well as fast charge transfer pathways display not only greatly promoted electrocatalytic activity but also high stability for OER. Remarkably, to achieve the current density of 10 mA cm−2, the optimal of CDs0.15-MnO2 requires the overpotential of only 343 mV and the relatively low Tafel slope of 43.6 mV dec−1. More significantly, such CDs0.15-MnO2 catalyst also displays outstanding long-term stability with limited activity and morphology change, showing an advanced class electrocatalyst. These findings open up a new way for the application of CDs and add to the growing family of CDs-metal hybrids with high OER performances.