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 × 10−8 to 2.0 × 10−3 M with a low detection limit of 3.0 × 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.

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► The photoelectrochemical behavior of G-TiO2/GCE was investigated in visible region.
► The G-TiO2/GCE possessed enhanced photocurrent than pure TiO2 nanocrystals.
► A photoelectrochemical sensor for ultrasensitive determination of NADH was proposed.
► The proposed sensor showed linear range of 1.0 × 10−8 to 2.0 × 10−3 M for NADH detection.
► This strategy largely reduces the destructive effect of UV light to biomolecules.