Ice‐Assisted Synthesis of Black Phosphorus Nanosheets as a Metal‐Free Photocatalyst: 2D/2D Heterostructure for Broadband H 2 Evolution

• Published in: Advanced functional materials Vol. 29; no. 28
• Main Authors: Zhang, Qingzhe, Huang, Shengyun, Deng, Jiujun, Gangadharan, Deepak Thrithamarassery, Yang, Fan, Xu, Zhenhe, Giorgi, Giacomo, Palummo, Maurizia, Chaker, Mohamed, Ma, Dongling
• Format: Journal Article
• Language: English
• Published: 01-07-2019
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201902486

Abstract
A 2D/2D heterojunction of black phosphorous (BP)/graphitic carbon nitride (g‐C
3
N
4
) is designed and synthesized for photocatalytic H
2
evolution. The ice‐assisted exfoliation method developed herein for preparing BP nanosheets from bulk BP, leads to high yield of few‐layer BP nanosheets (≈6 layers on average) with large lateral size at reduced duration and power for liquid exfoliation. The combination of BP with g‐C
3
N
4
protects BP from oxidation and contributes to enhanced activity both under λ > 420 nm and λ > 475 nm light irradiation and to long‐term stability. The H
2
production rate of BP/g‐C
3
N
4
(384.17 µmol g
−1
h
−1
) is comparable to, and even surpasses that of the previously reported, precious metal‐loaded photocatalyst under λ > 420 nm light. The efficient charge transfer between BP and g‐C
3
N
4
(likely due to formed NP bonds) and broadened photon absorption (supported both experimentally and theoretically) contribute to the excellent photocatalytic performance. The possible mechanisms of H
2
evolution under various forms of light irradiation is unveiled. This work presents a novel, facile method to prepare 2D nanomaterials and provides a successful paradigm for the design of metal‐free photocatalysts with improved charge‐carrier dynamics for renewable energy conversion.