Photoelectrochemical sensing of hydrogen peroxide using TiO2 nanotube arrays decorated with RGO/CdS

Abstract

Photoelectrochemical (PEC) sensing has great potential in the field of analytical chemistry due to its low cost, high sensitivity, simple equipment, and easy miniaturization. The design and construct of semiconductor materials used for photoanode with superior optoelectronic properties and excellent photoelectrochemical activity are vital for the realization of effective detection toward the analytes. In this paper, RGO/CdS–TiO2 (RGO, reduced graphene oxide) photoanodes were fabricated by two-step electrochemical anodic oxidation to form highly ordered TiO2 nanotube arrays (TNTs) firstly, then modified with RGO/CdS prepared by cyclic voltammetric electrodeposition. The resultant photoanodes were characterized by scanning electron microscope, X-ray diffraction, and UV–vis diffuse reflectance spectrophotometer as well as photoelectrochemical tests. The fabricated RGO/CdS(5)-TNTs PEC electrode exhibited good sensing for H2O2 with a 5-order wide linear range of 0.1 μM–10 mM and low detection limit of 0.002 μM. The obtained excellent PEC performance can be attributed to the synergistic effect of TNTs having high surface area and one-dimensional (1D) transport properties combined with RGO/CdS as electron collectors and transporters, offering efficient charge carrier separation and good electron transport.