Hematite decorated with Ni metal-organic framework for sensitive photoelectrochemical sensing of glucose

Photoelectrochemical (PEC) sensor is a simple and practical detection device with the advantages of low background signals and high sensitivity. In this work, a simple two-step post-calcination method was adopted to prepare alpha-Fe2O3 photoelectrode, followed by a Ni metal-organic framework (Ni-MOF) was deposited via a onestep solvothermal process, to obtain Ni-MOF/alpha-Fe2O3 photoelectrode, which was finally used for glucose sensing. The linear sweep voltammetry for glucose oxidation over Ni-MOF/alpha-Fe2O3 displayed a 0.24 V negative shift of initial potential and a significant photocurrent increase compared to bare alpha-Fe2O3, suggesting an accelerated glucose oxidation kinetics caused by Ni-MOF. (Photo)electrochemical characterizations revealed Ni-MOF could not only promote the charge separation but also provide active sites for glucose oxidation. As a result, Ni-MOF/ alpha-Fe2O3 demonstrated a superior sensing performance toward glucose in the concentration range of 0.002-1.6 mM at 0 V vs. SCE. Specially, when the concentration of glucose was 1 mM, the photocurrent of Ni-MOF/alpha-Fe2O3 was increased by 18-fold compared to alpha-Fe2O3. The Ni-MOF/alpha-Fe2O3 sensors also offered good selectivity, excellent reproducibility and remarkable long-term stability. Especially, the present Ni-MOF/alpha-Fe2O3 based PEC method exhibited comparable accuracy to high performance liquid chromatography (HPLC) in real sample analysis, such as bread and glucose solution. The results of this work would provide useful information for developing new semiconductor PEC glucose sensors.