Highly sensitive detection of nitrite by using gold nanoparticle-decorated alpha-Fe2O3 nanorod arrays as self-supporting photo-electrodes

摘要

Gold nanoparticle (AuNPs)-decorated alpha-Fe2O3 nanorod arrays (AuNPs-Fe2O3) were successfully fabricated by immersing hydrothermal-induced Fe2O3 nanorod arrays into HAuCl4 solution, followed by a simple reduction process. The obtained AuNPs on the alpha-Fe2O3 nanorods were about 3-5 nm in diameter. The photocurrent of AuNPs-Fe2O3 was twice as large as that of alpha-Fe2O3 nanorods. Benefiting from the good photoelectric properties, the proposed AuNPs-Fe2O3 can be directly utilized as a self-supporting photoelectrode for nitrite detection. As a result, the as-constructed sensor exhibited good photoelectron catalytic activity and selectivity, high sensitivity (0.1736 +/- 0.01 mu A mu M-1 cm(-2)) and a low limit of detection (0.07 mu M). The current response has a high linear correlation (R >= 0.999) in a wide range from 1 mu M to 1000 mu M and high stability. In addition, the as-constructed sensor was further employed for nitrite detection in tap and rain water samples to evaluate its practical applications.