Yanni Luo,Xuecai Tan,David J. Young,Quanyou Chen,Yuehui Huang,Defen Feng,Chenhao Ai,Yan Mi
In photoelectrochemical sensor (PEC sensor), sensitivity and selectivity are two essential factors which are determined by photosensitive of materials and identification of elements. Herein, a novel PEC aptamer sensor for streptomycin-specific detection was developed, with which the visible-light-active TiO 2 /BiOI/BiOBr heterostructure and aptamers were employed as photoactive material and bio-identification elements, separately. The combination of an appropriate amount of TiO 2 with BiOI/BiOBr enhanced the photocurrent response, and thus is beneficial to the construction of PEC sensors. In addition, the one-pot synthesis of TiO 2 /BiOI/BiOBr has the advantage of being environmentally-friendly. Under optimized conditions, the photocurrent response of aptamer/TiO 2 /BiOI/BiOBr/ITO is linear with SRT concentration from 0.05 to 150 nM, and the detection limit (S/N = 3) is as low as 0.04 nM. This novel PEC sensing strategy provided an ultra-sensitive sensor with high selectivity and stability for SRT detection.
Qianqian Ni,Xin Ke,Wenjing Qian,Zheng Yan,Jingde Luan,Wengang Liu
A single hydrothermal reaction was used to create BiOI/BiOBr composites, which demonstrated good sunlight-driven photocatalytic degradation activity of tetracycline (TC) over a broad pH range and the degradation efficiency can be stable at about 90%. Moreover,·O 2 - has been identified as the most important active ingredient in the photocatalytic system. Density functional theory (DFT) calculations were used to investigate the electron transfer mechanism of BiOX heterojunctions on a molecular scale, as well as to propose possible photocatalytic degradation mechanisms and reaction sites for tetracycline in different deprotonated forms at a wide range of pH values. The quantitative structure-activity relationship (QSAR) was also used to assess the toxicity of the intermediates. In summary, this study presents new concepts for investigating the photodegradation behavior of antibiotics throughout a wide pH range, which is predicted to be employed for surface water remediation.
Qianqian Ni,Huiping Shao,Yun Zhang,Xin Ke,Wengang Liu
Oxygen vacancies could be induced into the heterojunction structure of BiOI/BiOBr via high-temperature calcination. Light absorption, charge transfer efficiency, photocatalytic activity, and mechanism are all intimately connected to oxygen vacancies. Density-functional theory simulations demonstrate that surface oxygen vacancies adsorb oxygen to active sites, whereas bulk oxygen vacancies activate oxygen adsorbed to the surface to reactive radicals. Meanwhile, the addition of oxygen vacancies efficiently reduces the effects of background ions and pH on tetracycline breakdown in the real aquatic environment. The experimental results are consistent with the DFT calculations. This paper presents a straightforward approach for creating heterojunction surface and bulk-phase oxygen vacancies, as well as an understanding of the many roles that different types of oxygen vacancies play in the photocatalytic degradation process.
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