Modified Graphitic Carbon Nitride Nanosheets for Efficient Photocatalytic Hydrogen Evolution

• Published in: ChemSusChem 2019-11, Vol.12 (22), p.4996-5006
• Main Authors: Zhou, Xunfu, Zhu, Yating, Gao, Qiongzhi, Zhang, Shengsen, Ge, Chunyu, Yang, Siyuan, Zhong, Xinhua, Fang, Yueping
• Format: Article
• Language: English
• Subjects: Carbon; Carbon nitride; Charge transfer; cobalt; heterogeneous catalysis; hydrogen; Hydrogen evolution; Hydrogen production; Light irradiation; Nanosheets; nitrides; Photocatalysis; Photocatalysts; photochemistry; Pyrolysis; Quantum efficiency
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201901960

Considerable research efforts have been devoted to develop noble‐metal‐free cocatalysts coupled with semiconductors for highly efficient photocatalytic H2 evolution as part of the challenge toward solar‐to‐fuel conversion. Herein, a new cocatalyst with excellent activity in the electrocatalytic H2 evolution reaction (HER) that is based on Co sheathed in N‐doped graphitic carbon nanosheets (Co@NC) was fabricated by a surfactant‐assisted pyrolysis approach and then coupled with g‐C3N4 nanosheets to construct a 2 D‐2 D g‐C3N4/Co@NC composite photocatalyst by a simple grinding method. As a result of advantages in effective electrocatalytic HER activity, suitable electronic band structure, and rapid interfacial charge transfer brought about by the 2 D‐2 D spatial configuration, the g‐C3N4/Co@NC photocatalyst that contained 4 wt % Co@NC presented a high photocatalytic H2 generation rate of 15.67 μmol h−1 under visible‐light irradiation (λ≥400 nm), which was 104.5 times higher than that of pristine g‐C3N4. The optimum g‐C3N4/Co@NC photocatalyst showed a high apparent quantum efficiency of 10.82 % at λ=400 nm. Cobalt cocatalyst combination: A ternary g‐C3N4/Co@NC photocatalytic system, prepared by the judicious integration of a 2 D Co@NC (graphene‐like nanosheets) cocatalyst and 2 D g‐C3N4 photocatalyst, is used for efficient hydrogen evolution in triethanolamine solution or pure water.