Study on enzyme-free glucose sensor based on Au and CuO co-modified TiO2 films for photoelectrochemical detection

Currently, widely used glucose sensors rely on enzyme catalysts, which suffer from issues such as enzyme inactivation, high production costs, and insufficient stability. To address these challenges, this study fabricated TiO₂ films on Ti sheets using radio frequency magnetron sputtering and subsequently modified Au nanoparticles (NPs) and CuO films via direct current magnetron sputtering. Then, Au and CuO co-modified TiO₂ (CuO-Au@TiO₂) photoelectrode with a Z-type band structure was prepared, enabling enzyme-free glucose detection via photoelectrochemical (PEC) sensing technology. The optimized photoelectrode exhibited high sensitivity for glucose detection, with values of 7300 μA μM⁻¹ cm-²(0–1 mM) and 500 μA μM⁻¹ cm⁻² (1–10 mM) under AM 1.5G illumination at a bias of 0.2 V (vs. Ag/AgCl). The detection limit was determined to be 58.14 μM (Signal/Noise = 3), with excellent stability, repeatability, and selectivity. Spectral and PEC performance analyses revealed that the outstanding sensing performance of the CuO-Au@TiO₂ photoelectrode can be attributed to: (1) unique Z-Type band structure promoting carrier separation; (2) the local surface plasmon resonance (LSPR) effect induced by Au NPs enhancing light absorption; (3) CuO can undergo a specific enzyme-like catalytic reaction with glucose molecules under alkaline conditions. This research offers a novel, convenient, and accurate monitoring approach for diabetes management and prevention.