Black Ultrathin Single‐Crystalline Flakes of CuVP<sub>2</sub>S<sub>6</sub> and CuCrP<sub>2</sub>S<sub>6</sub> for Near‐Infrared‐Driven Photocatalytic Hydrogen Evolution
Bo Lin, Ruihuan Duan, Yonghui Li, Weibo Hua, Ruhong Zhou, Jiadong Zhou, Jun Di, Xiao Luo, He Li, Wenting Zhao, Guidong Yang, Zheng Liu, Fucai Liu
Abstract
Abstract The development of new near‐infrared‐responsive photocatalysts is a fascinating and challenging approach to acquire high photocatalytic hydrogen evolution (PHE) performance. Herein, near‐infrared‐responsive black CuVP 2 S 6 and CuCrP 2 S 6 flakes, as well as CuInP 2 S 6 flakes, are designed and constructed for PHE. Atom‐resolved scanning transmission electron microscopy images and X‐ray absorption fine structure evidence the formation of ultrathin single‐crystalline sheet‐like structure of CuVP 2 S 6 and CuCrP 2 S 6 . The synthetic CuVP 2 S 6 and CuCrP 2 S 6 , with a narrow bandgap of ≈1.0 eV, shows the high light‐absorption edge exceeding 1100 nm. Moreover, through the femtosecond‐resolved transient absorption spectroscopy, CuCrP 2 S 6 displays the efficient charge transfer and long charge lifetime (18318.1 ps), which is nearly 3 and 29 times longer than that of CuVP 2 S 6 and CuInP 2 S 6 , respectively. In addition, CuCrP 2 S 6 , with the appropriate d‐band and p‐band, is thermodynamically favorable for the H + adsorption and H 2 desorption by contrast with CuVP 2 S 6 and CuInP 2 S 6 . As a result, CuCrP 2 S 6 exhibits high PHE rates of 9.12 and 0.66 mmol h −1 g −1 under simulated sunlight and near‐infrared light irradiation, respectively, far exceeding other layered metal phospho–sulfides. This work offers a distinctive perspective for the development of new near‐infrared‐responsive photocatalysts.