Single-atom Pt supported on holey ultrathin g-C₃N₄ nanosheets as efficient catalyst for Li-O₂ batteries

As for electrocatalysis, single-atom metal catalysts have been proved to lower the cost and utilize precious metals more efficiently. Herein, single-atom Pt catalyst supported on holey ultrathin g-C₃N₄ nanosheets (Pt-CNHS) was synthesized via a facile liquid-phase reaction of g-C₃N₄ and H₂PtCl₆. The single-atom Pt can achieve high dispersibility and stability, which can promote the utilization efficiency as well as enhance the electrochemical activity. When employed as Li-O₂ batteries' cathode catalyst, Pt-CNHS exhibits excellent electrocatalytic activity. Li-O₂ batteries utilizing Pt-CNHS show much higher discharge specific capacities than those with pure CNHS. Li-O₂ batteries with Pt-CNHS cathode can be cycled stably for 100 times under the discharge capacity of 600 mAh g^-1. Based on experimental results and density functional theory calculations, the superior electrocatalytic activity of Pt-CNHS can be ascribed to the large surface area, the enhanced electrical conductivity and the efficient interfacial mass transfer through Pt atoms and porous structure of CNHS.