Sonoelectrochemical exfoliation of defective black phosphorus nanosheet with black phosphorus quantum dots as a uric acid sensor

To maintain human health, the development of rapid uric acid (UA) sensing is crucial. In this study, defective black phosphorus nanosheets with black phosphorus quantum dots (dBPN/BPQDs) were successfully and rapidly prepared by sonoelectrochemical exfoliation. In this process, the intercalation of phosphate ions into the black phosphorus working electrode was improved by coupling ultrasonic radiation with a high intercalating potential (8 V vs. Ag/AgCl/3M). The dBPN/BPQDs with various vacancies (5-9 defects, 5-7-7-5 defects, and 5-8-5 defect vacancies) exhibited a remarkable mass activity (j_m, 1.22 × 10^-3 mA μg^-1) for uric acid oxidation, which was 5.92 times greater than that of reduced graphene oxide (rGO) (2.06 × 10^-4 mA μg^-1). In addition, the sensitivity of the dBPN/BPQD UA sensor was 474.2 μA mM^-1 cm^-2 in the linear analysis range of 0.1-1.3 mM. The sensitivity of the sensor was apparently higher than 67.7 μA mM^-1cm^-2 for rGO. The data from real sample experiments using serum showed that the dBPN/BPQD catalyst had high recoveries (97.3 %-100.2 %) and low related standard deviation (0.44 %-1.52 %). The dBPN/BPQDs exhibited the potential as an amperometric sensor to detect UA without needing enzymes.