Bioelectrocatalytic performance of glucose oxidase/nitrogen‐doped titania nanotube array enzyme electrode

BACKGROUND The substrate materials of enzyme electrodes strongly affect bioelectrocatalytic activity. TiO 2 nanotube arrays ( NTAs ) show good affinity to glucose oxidase ( GOx ) but low conductivity. TiN NTAs show good conductivity but low affinity to GOx . Nitrogen‐doped TiO 2 (N‐ TiO 2 ) NTA with good hydrophilicity and conductivity was designed to prepare a GOx /N‐ TiO 2 NTA enzyme electrode to promote bioelectrocatalytic performance. RESULTS N‐ TiO 2 NTA had a well‐ordered nanoarray structure with slightly distorted pore mouth and wrinkled nanotube wall. N‐ TiO 2 NTA exhibited decreased charge transfer resistance and similar contact angle to TiO 2 NTA , presenting high electrical conductivity and good hydrophilicity. GOx /N‐ TiO 2 NTA exhibited highly increased current response at a potential of −0.45 V, presenting good bioelectrocatalysis towards glucose. A GOx /N‐ TiO 2 NTA enzyme electrode was used to fabricate a glucose biosensor, showing a high sensitivity of 733.17 µA mM −1 cm −2 and a linear range of 0.05–0.85 mmol L −1 and low detection limit of 2.9 µmol L −1 for glucose determination. It exhibited high selectivity in the presence of common interfering substances and was used to determine glucose in serum. It also had good reproducibility and long‐time storage stability. In addition, the GOx /N‐ TiO 2 NTA enzyme electrode was used to fabricate a glucose fuel cell, showing maximum power density of 23.92 µW cm −2 as well as good bioelectrocatalytic stability. CONCLUSION High bioelectrocatalytic activity and stability of GOx /N‐ TiO 2 NTA proved that N‐ TiO 2 NTA could act as a reasonable supporting substrate material for enzyme electrodes for various bioelectrocatalytic applications. © 2015 Society of Chemical Industry