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

•A non-enzymatic photoelectrochemical (PEC) H2O2 sensor has been constructed.•The sensor consists of Ta3N5 nanotube electrode, without any other catalysts.•High sensitivity of 167.9 uA cm−2 mM−1 has been obtained for H2O2 sensing.•The work expands the application of Ta3N5 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 (Ta3N5) photoanode is fabricated for PEC H2O2 sensor through an anodization procedure combined with subsequent nitridation in NH3 atmosphere. The crystalline phase, morphology and light adsorption property of Ta3N5 are characterized by X-ray diffraction, scanning electron microscope and UV–vis diffuse reflectance spectrophotometer, the results show that Ta3N5 has nanotube structure and can absorb light to 620 nm. The PEC tests exhibit Ta3N5 photoelectrode has much higher current and lower onset potential for hydrogen peroxide (H2O2) oxidation than H2O oxidation, indicating H2O2 possesses faster reaction kinetics over Ta3N5 surface. Furthermore, the Ta3N5 photoelectrode exhibited a high sensitivity of 167.9 μA cm−2 mM−1 for H2O2 determination in the concentration range of 0.1 ∼ 2.6 mM. It is supposed that the fast extraction of hole by H2O2 on the Ta3N5 electrode surface is the key for the high sensing performance achieved in our fabricated PEC sensor.