One-pot synthesis of BiPO4 functionalized reduced graphene oxide with enhanced photoelectrochemical performance for selective and sensitive detection of chlorpyrifos

Abstract

The design and exploitation of photoelectrochemical (PEC) sensors with advanced nanomaterials is of great importance to achieving the goal of sensitive and inexpensive detection. In this paper, a series of bismuth phosphate (BiPO₄) functionalized reduced graphene oxide (BiPO₄–rGO) nanocomposites (NCs) were prepared using a one-step solvothermal method. Compared with the pure BiPO₄ nanoparticles (NPs), all of the as-prepared BiPO₄–rGO NCs with different starting mass ratios of graphene oxide (GO) to BiPO₄ showed an enhanced PEC response. On this basis, the BiPO₄–rGO_0.03 NCs (the starting mass ratio of GO to BiPO₄ = 0.03) with the best PEC response were used for the PEC determination of chlorpyrifos. With the addition of chlorpyrifos, the formation of a Bi–chlorpyrifos complex on the BiPO₄ NPs gave rise to an increase in steric hindrance which caused the electron transfer of BiPO₄ NPs to trail off towards the electrode surface, and consequently resulted in an obvious decrease in photocurrent. The designed PEC sensor displayed a linear response for chlorpyrifos in the range from 0.05 to 80 ng mL⁻¹ with a low detection limit of 0.02 ng mL⁻¹ (S/N = 3). The common interferents such as methyl parathion, pentachlorophenol, and carbaryl had no obvious influence on the detection of chlorpyrifos, although these substances were reported to influence the PEC sensing of chlorpyrifos to some extent. The applicability of this method was also investigated by the determination of chlorpyrifos in wastewater samples with satisfactory results. Thus, it is expected that the resulting BiPO₄–rGO NCs can serve as a potential photoactive material for PEC sensing related applications.