Oxygen vacancy-regulated TiO2 nanotube photoelectrochemical sensor for highly sensitive and selective detection of tetracycline hydrochloride

Investigation of the mechanism of oxygen vacancy-regulated photoelectrochemical sensors for highly sensitive and selective determination of biomolecules containing electron-donating groups is an innovative research field. In this study, oxygen vacancy-regulated TiO2 nanotube arrays (Ov-TNTs) with high photoelectrochemical ac-tivity were synthesized and applied to defect tetracycline hydrochloride (TC). The synergistic effect of oxygen vacancies and Ti3+ droves Ov-TNTs with a narrow energy band to generate more photogenerated carriers under irradiation. The photocurrent response of the oxygen vacancy-regulated photoelectrochemical sensor decreased with increasing TC concentration, which could be mainly attributed to adsorption of TC, which consumed part of the oxygen vacancies on the surface of Ov-TNTs. This system had excellent linearity in the range of 0.1-1000 nM with a detection limit of 0.33 nM (S/N = 3). In addition, the sensor was highly selective for TC determination due to the mutual electrostatic interaction between negatively charged TC-containing electron-donating groups (-NH2 and-OH) and positively charged Ov-TNTs. This study provided a foundation for developing an oxygen vacancy-regulated adsorptive photoelectrochemical sensor.

Automated summary

Investigation into the mechanism of oxygen vacancy-regulated photoelectrochemical sensors for highly sensitive and selective detection of biomolecules with electron-donating groups is an innovative research field. This study synthesized oxygen vacancy-regulated TiO2 nanotube arrays with high photoelectrochemical activity and applied them to detect tetracycline hydrochloride. The synergistic effect of oxygen vacancies and Ti3+ in the nanotube arrays led to increased generation of photogenerated carriers, while the adsorption of tetracycline hydrochloride consumed the oxygen vacancies and decreased the photocurrent response of the sensor. The sensor showed excellent linearity in the range of 0.1-1000 nM and high selectivity for tetracycline hydrochloride determination.