Two‐dimensional metallic CoTe <sub>2</sub> flakes for electrocatalytic hydrogen evolution
Yu‐Qing Zhao, Qian Liu, Bojian Zhou, Guang Yang, Shaolong Jiang
Abstract
Abstract Two‐dimensional (2D) metallic 1T‐CoTe 2 has attracted considerable attention due to its fascinating physical properties and promising applications in electronics and catalysis. However, the production of high‐quality 2D 1T‐CoTe 2 still remains challenging. Herein, we demonstrate a methodology to realize the facile synthesis of ultrathin, high‐quality CoTe 2 flakes with a thickness down to 2.3 nm on mica substrates by an ambient‐pressure chemical vapor deposition (CVD) technique. The atomic arrangement is verified by scanning transmission electron microscopy. The theoretical calculations uncover the metallic characteristic of 1T‐CoTe 2 in the 2D limit. Remarkably, the CVD‐derived 2D metallic CoTe 2 flakes for the hydrogen evolution reaction (HER) catalyst exhibit admirable performance, such as an overpotential of 186 mV at 10 mA·cm −2 , a Tafel slope of 78 mV·dec −1 , an exchange current density of 69 μA·cm −2 , and negligible performance degradation after 1000 cycles. These results establish novel approaches for the synthesis and HER application of 2D metallic 1T‐CoTe 2 .