Integrated BiPO4 nanocrystal/BiOBr heterojunction for sensitive photoelectrochemical sensing of 4-chlorophenol

Abstract

It is generally known that pollution by 4-chlorophenol (4-CP) raises environmental concerns owing to the high toxicity of 4-CP. The necessity for determining and controlling the presence of 4-CP in the aqueous environment to achieve good water-quality objectives is now well recognized. Thus, a sensitive photoelectrochemical (PEC) sensing platform was fabricated on the basis of a BiPO₄ nanocrystal/BiOBr (BiPO₄/BiOBr) heterojunction for monitoring 4-CP. The BiPO₄/BiOBr heterojunction was prepared using an in situ hydrothermal route assisted by the ionic liquids 1-hexadecyl-3-methylimidazolium bromide ([C₁₆mim]Br) as the source of Br, and 1-octyl-3-methylimidazolium dihydrogen phosphate ([Omim]H₂PO₄) as the P source. Ionic liquids can also act as morphological templates, and have been considered to offer a suitable green route to nanocrystal synthesis. The resultant BiPO₄/BiOBr heterojunction presented a higher PEC response than BiOBr. The BiPO₄/BiOBr/ITO displayed an obvious photocurrent increment against 160 ng mL⁻¹ 4-CP, and therefore a PEC sensing platform on the basis of a BiPO₄/BiOBr heterojunction was fabricated for monitoring 4-CP. This PEC sensor exhibited a wide linear range from 8.00 to 2400.00 ng mL⁻¹ with a low detection limit, high selectivity, and good anti-interference properties. The as-prepared PEC sensor is expected to be utilized to determine 4-CP, and offers an important analytical method for rapid detection in real samples.