Ultrasensitive photoelectrochemical sensing of nicotinamide adenine dinucleotide based on graphene-TiO2 nanohybrids under visible irradiation

In this paper, the photoelectrochemical behavior of graphene-TiO2 (G-TiO2) nanohybrids was investigated in the visible region and a new photoelectrochemical sensor for sensitive determination of nicotinamide adenine dinucleotide (NADH) was proposed. Under visible light, the G-TiO2 nanohybrids possessed enhanced photocurrent, which was nearly 5 times than that of pure TiO2 nanocrystals (NCs). Based on the enhanced photocurrent of G-TiO2 nanohybrids toward NADH, a new photoelectrochemical methodology for ultrasensitive determination of NADH was developed. The proposed sensor showed linearly enhanced photocurrent by increasing the NADH concentration from 1.0 x 10(-8) to 2.0 x 10(-3) M with a low detection limit of 3.0 x 10(-9) M. Furthermore, this sensor exhibited good selectivity and stability towards NADH determination. This strategy opens up a new avenue for the application of graphene-based hybrids in the field of photoelectrochemical sensing and monitoring. (C) 2012 Elsevier B.V. All rights reserved.