Carbon dot intercalated MXene with an excellent oxygen reduction reaction electrocatalytic performance

The design of non-metallic electrocatalysts with high activity and prolonged durability in alkaline environments is essential for the development of efficient, cost-effective and simplified electrocatalytic oxygen reduction systems. Layer-restacking is the bottleneck restricting its ion dynamics and active site exposure, and carbon dot (CD) intercalation MXene can prevent layers of MXene restacking. Here, we report a novel MXene/CD composite composed of layered MXene templates and zero-dimensional carbon dot particles. The composite material was synthesized by the strong interaction between CD and MXene core. In the process of mutual combination, CD can be embedded into MXene nanosheets, increasing the interlayer spacing and promoting the electrolytic diffusion between MXene sheets. Therefore, MXene/CD nanodot hybrids exhibit good ORR catalytic activity. In 0.1 M KOH solution, the half-wave potential of MXene/CD was 0.78 V, and diffusion limiting current density was 5.6 mA cm⁻². Additionally, after 50,000 s of cyclic operation tests, the relative current density has decayed by only 3.8%, demonstrating excellent stability.