Tantalum nitride nanotube structured electrode for non-enzymatic hydrogen peroxide sensing via photoelectrochemical route

Abstract

• A non-enzymatic photoelectrochemical (PEC) H 2 O 2 sensor has been constructed. • The sensor consists of Ta 3 N 5 nanotube electrode, without any other catalysts. • High sensitivity of 167.9 uA cm −2 mM −1 has been obtained for H 2 O 2 sensing. • The work expands the application of Ta 3 N 5 in the field of chemical analysis. Photoelectrochemical (PEC) sensing holds great promise in the field of analytical chemistry owing to its high sensitivity, low cost and simple equipment. In this paper, tantalum nitride (Ta 3 N 5 ) photoanode is fabricated for PEC H 2 O 2 sensor through an anodization procedure combined with subsequent nitridation in NH 3 atmosphere. The crystalline phase, morphology and light adsorption property of Ta 3 N 5 are characterized by X-ray diffraction, scanning electron microscope and UV–vis diffuse reflectance spectrophotometer, the results show that Ta 3 N 5 has nanotube structure and can absorb light to 620 nm. The PEC tests exhibit Ta 3 N 5 photoelectrode has much higher current and lower onset potential for hydrogen peroxide (H 2 O 2 ) oxidation than H 2 O oxidation, indicating H 2 O 2 possesses faster reaction kinetics over Ta 3 N 5 surface. Furthermore, the Ta 3 N 5 photoelectrode exhibited a high sensitivity of 167.9 μA cm −2 mM −1 for H 2 O 2 determination in the concentration range of 0.1 ∼ 2.6 mM. It is supposed that the fast extraction of hole by H 2 O 2 on the Ta 3 N 5 electrode surface is the key for the high sensing performance achieved in our fabricated PEC sensor.