A Highly Sensitive Visible-Light Photoelectrochemical Sensor for Pentachlorophenol Based on Synergistic Effect of 2D TiO₂ Nanosheets and Carbon Dots

Abstract

A new visible-light photoelectrochemical (PEC) sensor based on 2D graphene-like TiO 2 nanosheets and carbon dots nanocomposites modified glassy carbon electrode (TiO 2 NSs/C-dots/GCE) is developed for pentachlorophenol (PCP) detection. The 2D TiO 2 NSs and C-dots are both synthesized by one-step solvothermal methods and the TiO 2 NSs/C-dots nanocomposites are prepared by a simple physical mixing method. The C-dots could effectively reduce the recombination of electrons and holes in the nanocomposites, improve the excitation conversion efficiency in visible-light area, and thus remarkably amplify the PEC signal. The PEC signal for PCP at the TiO 2 NSs/C-dots/GCE sensor is about 11-times and 3.2-times larger than that at the C-dots/GCE and TiO 2 NSs/GCE, respectively. The TiO 2 NSs/C-dots/GCE sensor exhibits a wide linear proportion to the PCP concentration in the range from 0.1 to 4.5 nM with a detection limit of 0.05 nM (3S N −1 ). Moreover, the TiO 2 NSs/C-dots/GCE sensor also shows high selectivity, excellent stability, and good repeatability in PCP determination. Furthermore, the TiO 2 NSs/C-dots/GCE sensor is further applied to determinate PCP in practical water samples.

Carbon-based photoelectrochemical sensors: recent developments and future prospects

“…2A). Fu et al 64 used a TiO 2 and CQD nanocomposite for the PEC detection of pentachlorophenol. In this composite, the photogenerated electrons of the CQDs migrated along the interface to the CB of TiO 2 , whereas the holes were unable to migrate to the VB of TiO 2 , thus hindering electron–hole combination.…”

Solvent-controlled synthesis of hydrophilic and hydrophobic carbon dots

“…3 To precisely regulate the luminescence properties of CDs and develop new applications, various methods have been developed to modulate their physical and chemical properties, [4][5][6] such as doping with heteroatoms, 7 covalent modifications, and non-covalent modifications. This has enabled the expansion of the application of CDs in sensors, [8][9][10] biological imaging, 11,12 photoelectric catalysis, [13][14][15] fluorometric probe, [16][17][18] and optoelectronic devices. 19,20 The tuning of hydrophilicity and hydrophobicity of CDs is important in surface manipulation.…”