Two-dimensional ytterbium oxide nanodisks based biosensor for selective detection of urea

Herein, we demonstrate synthesis and application of two-dimensional (2D) rectangular ytterbium oxide (Yb2O3) nanodisks via a facile hydrothermal method. The structural, morphological, compositional, crystallinity, and phase properties of as-synthesized nanodisks were carried out using several analytical techniques that showed well defined 2D rectangular nanodisks/sheet like morphologies. The average thickness and edge length of the nanosheet structures were 20 +/- 5 nm and 600 +/- 50 nm, respectively. To develop urea biosensor, glassy carbon electrodes (GCE) were modified with Yb2O3 nanodisks, followed by urease immobilization and Nafion membrane covering (GCE/Yb2O3/Urease/Nafion). The fabricated biosensor showed sensitivity of 124.84 mu A mM(-1) cm(-2), wide linear range of 0.05-19 mM, detection limit down to similar to 2 mu M, and fast response time of similar to 3 s. The developed biosensor was also used for the urea detection in water samples through spike recovery experiments, which illustrates satisfactory recoveries. In addition, the obtained desirable selectivity towards specific interfering species, long-term stability, reproducibility, and repeatability further confirm the potency of as-fabricated urea biosensor.