23January2020

Nano-Micro Letters

Experimental and DFT Studies of Au Deposition Over WO3/g-C3N4 Z-Scheme Heterojunction

Muhammad Humayun1, 2, Habib Ullah3, Junhao Cao1, Wenbo Pi1, Yang Yuan1, Sher Ali1, Asif Ali Tahir3, Pang Yue4, Abbas Khan5, Zhiping Zheng1, Qiuyun Fu1, Wei Luo1, 2, *

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Nano-Micro Lett. (2020) 12: 7

First Online: 19 December 2019 (Article)

DOI:10.1007/s40820-019-0345-2

*Corresponding author. E-mail: luowei@mail.hust.edu.cn (Wei Luo)

 

Abstract

 


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A typical Z-scheme system is composed of two photocatalysts which generate two sets of charge carriers, and split water into H2 and O2, at different locations. Scientists are struggling to enhance the efficiencies of these systems by maximizing their light absorption, engineering more stable redox couples, and discovering new O2 and H2 evolutions co-catalysts. In this work, Au decorated WO3/g-C3N4 Z-scheme nanocomposites have been fabricated for the first time via wet-chemical and photo-deposition methods. The nanocomposites are utilized in photocatalysis for H2 production and 2,4-dichlorophenol (2,4-DCP) degradation. It is investigated that the optimized 4Au/6%WO3/CN nanocomposite is highly efficient for production of 69.9 and 307.3 µmol h-1 g-1 H2 gas, respectively, under visible-light (λ>420 nm) and UV-visible illumination. Further, the fabricated 4Au/6%WO3/CN nanocomposite is significant (i.e., 100% degradation in 2 h) for 2,4-DCP degradation under visible-light and highly stable in photocatalysis. A significant 4.17% quantum efficiency is recorded for H2 production at wavelength 420 nm. This enhanced performance is attributed to the improved charge separation and the surface plasmon resonance effect of Au nanoparticles. Solid-state density functional theory simulations are performed to countercheck and validate our experimental data. Positive surface formation energy, high charge transfer, and strong non-bonding interaction via electrostatic forces confirm the stability of 4Au/6%WO3/CN interface.


 

Keywords

Polymeric g-C3N4; Plasmonic Au; Charge separation; Solar H2 production; DFT calculations

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