Facile wet chemical method for fabricating p-type BiOBr/n-type nitrogen doped graphene composites: Efficient visible-excited charge separation, and high-performance photoelectrochemical sensing

The development of highly efficient visible-excited charge separation photo active materials has attracted great attention for solving the global energy crisis and environmental problems. In this paper, p-type BiOBr nanoplates decorated n-type nitrogen doped graphene (BiOBr-NGR) composites are constructed by a facile wet chemical method. The formation of p-n junctions was beneficial to the efficient visible-excited charge transfer, and effectively restrains the recombination of photoinduced electron-hole pairs, resulting enhanced photoelectrochemical (PEC) performance. In particular, it is shown by means of the transient-state surface photocurrent responses that the photocurrent intensity of the as-fabricated composites exhibited 2.6 times higher than that of pristine BiOBr. Based on the robust photocurrent signal, a novel PEC sensor based on BiOBr-NGR was established for sensitive and selective detection of chlorpyrifos. The as-fabricated PEC sensor demonstrates many advantages such as wide linear range (5 pg mL−1-11.6 ng mL−1), low detection limit (1.67 pg mL−1, S/N = 3), and remarkably convenient, which provides a general format for chlorpyrifos detection in food and environment analysis.