Ultrafast and large-scale synthesis of Co3O4 quantum dots-C3N4/rGO as an excellent ORR electrocatalyst via a controllable deflagration strategy

Abstract Transition metal quantum dots (QDs) are ideal electrocatalysts due to their short ion diffusion path, high atom utilization and effective electron transfer properties. However, a lack of facile and large-scale synthesis strategy limits their industrial production and commercial application. In this study, a triaminoguanidine salt-induced one-step deflagration method is first reported for the ultrafast (hundreds of milliseconds) and gram-scale synthesis of Co3O4 QDs-C3N4/rGO as an efficient oxygen reduction reaction (ORR) catalyst with high durability. The deflagration reaction process is carefully studied and the formation mechanism is proposed to explain the controllable synthesis of Co3O4 QDs. An optimized sample is capable of achieving an excellent ORR performance in terms of an onset potential of 0.97 V (vs. RHE, equivalent to Pt/C) and the limited current density of −5.33 mA·cm−2 at 0.35 V (vs. RHE, ~7% higher than that of Pt/C). It is believed that this simple and effective synthesis strategy will open up an exciting new avenue to the future design and facile synthesis of Co3O4 or other QDs-based functional materials.