Micro and nano hierachical structures of BiOI/activated carbon for efficient visible-light-photocatalytic reactions

Jianhua Hou,Rui Wei,Kun Jiang,Ming Shen,Xiaoge Wu,Chuanbao Cao,Faryal Idrees

doi:10.1038/s41598-017-12266-x

Jianhua Hou, Rui Wei + Show 5 more

Open Access

https://doi.org/10.1038/s41598-017-12266-x

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Abstract

Constructing the heterojunctions or designing the novel nanostructures are thought as effective methods to improve photocatalytic activities of semiconductors. Herein, a one-step green route was developed to fabricate bismuth oxyiodide/activated carbon (BiOI/C) composite. The prepared BiOI/C exhibit obviously red shifts and increased absorption range of visible light. The presence of Bi-C bonds confirms the heterojunction, on account of which the BiOI nanosheets tightly grew on the surface of carbon and subsequently provided the hierarchical structure, sufficient interfacial interaction and high specific surface area. Significantly, the sufficient interracial interaction is beneficial to the detachment of electrons (e−)-holes (h+) pairs and the Bi-C bonds work like a bridge to rapidly transmit the e− from BiOI to carbon. What’s more, the hierarchical structure of BiOI/C efficiently shortened the diffusion pathways of pollutants and the high SBET provided more exposed reaction sites. Benefiting from multiple synergistic effects, the as-prepared BiOI/C exhibited enhanced photocatalytic activities in degrading Rhodamine B (RhB) solution under visible light irradiation. The degradation rate of optimized BiOI/C reaches up to 95% in 120 min, and the efficiency is 3.36 times higher than pure BiOI. This study provides a promising strategy that activated carbon can be utilized in highly-efficiency photocatalysts.

Highlights

In past few years, the water pollution and energy crisis problems have seriously threatened the sustainable development of human beings[1]
Different strategies have been adopted to improve photocatalytic response of BiOI, such as, (i) designing a novel nanostructures to increase SBET to provide more active sites for reaction[18,19]; (ii) constructing a hierarchical structures to shorten the pathways of water pollutants[20,21]; (iii) establishing a heterojunction with other semiconductors to prevent the recombination of the e−–h+ pairs and to facilitate the advance quantum efficiency[22,23]
The X-ray powder diffraction (XRD) spectrum of BiOI and bismuth oxyiodide/activated carbon (BiOI/C) is shown in Fig. 2a, the diffraction peaks of BiOI at 24.3, 29.6, 31.6, 45,4, 55.1, 66.1 and 75.1° are corresponding to (101), (102), (110), (200), (212), (220) and (210) plane, respectively, which well match with the tetragonal phase structure (JCPDS No.10-0445)[28], demonstrating the high purity of the sample

Summary

Introduction

The water pollution and energy crisis problems have seriously threatened the sustainable development of human beings[1]. The low quantum yield, weak photo-oxidation ability and easy recombination of e−–h+ pairs of BiOI still hinder its photocatalytic property[17] Regarding these drawbacks, different strategies have been adopted to improve photocatalytic response of BiOI, such as, (i) designing a novel nanostructures to increase SBET to provide more active sites for reaction[18,19]; (ii) constructing a hierarchical structures to shorten the pathways of water pollutants[20,21]; (iii) establishing a heterojunction with other semiconductors to prevent the recombination of the e−–h+ pairs and to facilitate the advance quantum efficiency[22,23]. The commercial activated carbon with high SBET30 can effectively overcome this problem By compositing it with BiOI via a green, facile and low cost method, the BiOI/C is expected to show broadened absorption range of visible light, as well as enhanced photocatalytic property. The multiple synergistic effects of these characteristics dramatically improve the photocatalytic property of BiOI/C for water pollutants degradation

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