Ultrathin-Layer Structure of BiOI Microspheres Decorated on N-Doped Biochar With Efficient Photocatalytic Activity.

Jianhua Hou,Ting Jiang,Faryal Idrees,Rui Wei,Detlef Bahnemann

doi:10.3389/fchem.2019.00378

Jianhua Hou, Ting Jiang + Show 3 more

Open Access

https://doi.org/10.3389/fchem.2019.00378

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Abstract

Bismuth oxyiodide (BiOI) is among the most potential photocatalysts due to its photocatalytic activity under visible light irradiation. However, the photoinduced carrier separation efficiency has limited the BiOI photocatalytic activity. Herein, we utilized the direct carbonation of sapless cattail grass to obtain N-doped hierarchical structure cattail-based carbon (NCC). The NCC not only served as an appropriate host but also as a self-sacrificing template for BiOI microspheres for the preparation of BiOI/NCC composite material. The acidic solutions (HCl or AcOH) were used as a solvent which helped to obtain a well-defined micro/nano hierarchical BiOI microspheres composed of ultrathin nanosheets. Thus, BiOI/NCC composites were successfully designed through the in-situ self-template rapid dissolution-recrystallization mechanism. Additionally, numerous well-contacted interfaces were formed between NCC and BiOI, which served as an electron-acceptor bridge function for ultrafast electron transfer process in order to hinder the electron-hole pairs recombination. On account of the multiple synergistic effects of micro/nano hierarchical microsphere structure, ultrathin nanosheets, and well-contacted interface, the as-prepared BiOI/NCC composites exhibit the superior degradation of rhodamine B (RhB) than pure BiOI under visible light irradiation.

Highlights

Photocatalysis technology is believed to be a green technology with great potential to thoroughly degrade refractory organic pollutants into non-toxic or low-toxic small molecules by using semiconductor materials as photocatalysts (Hoffmann et al, 1995; Jin et al, 2017)
Bismuth oxyiodide (BiOI)/N-doped hierarchical structure cattail-based carbon (NCC) samples were produced by the following procedure: 60 mg of NCC was put into a round bottom bottle with a mixture of 50 mL ethylene glycol (EG) and 50 mL distilled water during continuous magnetic stirring, 10 mmol Bi(NO3)3·5H2O was added in the reaction system
Self-assembled BiOI microspheres with ultrathinlayer structure loaded on biochar (N-doped cattail-based carbon, NCC), namely BiOI/NCC composite materials were produced through one-step, green and facile approach by the in-situ self-template

Summary

Introduction

Photocatalysis technology is believed to be a green technology with great potential to thoroughly degrade refractory organic pollutants into non-toxic or low-toxic small molecules by using semiconductor materials as photocatalysts (Hoffmann et al, 1995; Jin et al, 2017). The ultrathinlayer formation is recognized as a promising new method, mainly because it enables the photoinduced charge carriers to generate faster transmission to reach the surface of BiOI, leading to superior separation of photoinduced electrons and holes in semiconductor (Zhang et al, 2014; Jiang et al, 2017). Jiang et al (2017) synthesized hollow flowerlike BiOI semiconductor (h-BiOI) with ultrathin nanosheets (the thickness is around 2 nm) using a solvothermal method, which displays improved activity in visible light irradiation. Di et al (2018) fabricated controllable N-doped carbon quantum dots (N-CQDs) with modified BiOI nanosheets nano-junctions, that improve the photocatalytic activity. It is still a challenge to construct the optimized structure with ultrathinlayer in BiOI/N-doped carbon composites via a one-step, facile and green preparation method

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