Oxygen Vacancy-Enriched MXene Nanosheets Coated with MoO_3-x for Glucose Monitoring

Accurate glucose monitoring is crucial for managing diabetes, a chronic metabolic disorder that affects millions of individuals worldwide. While enzymatic glucose sensors dominate the market, they still have many limitations, such as enzyme instability, high cost, and susceptibility to environmental conditions, which highlights the need for nonenzymatic alternatives with improved stability, sensitivity, and cost-effectiveness. In this work, we presented a straightforward design of a heterostructure multilayer system based on MXene nanosheets coated with oxygen vacancy-enriched molybdenum trioxide (MoO_3-x/MXene) and thus developed a highly sensitive nonenzymatic glucose sensor. A solvothermal reaction effectively introduced a high concentration of oxygen vacancies into MoO₃, thereby optimizing its intrinsic electrical conductivity. The stable colloidal solutions of MoO_3-x nanobelts and MXene nanosheets were uniformly integrated by van der Waals interactions, thus resulting in the formation of the heterostructure multilayer system. The remarkable conductivity of the MoO_3-x/MXene heterostructure, coupled with its abundant active sites, significantly enhanced the electrocatalytic efficiency for glucose oxidation. The MoO_3-x/MXene nanocomposites demonstrated a wide glucose detection range from 0.002 to 9 mM. Amperometry testing showed a rapid response and recovery time. Besides, the as-fabricated sensor displayed an excellent anti-interference performance. The results indicate that the MoO_3-x/MXene nanocomposites have great prospects in the field of nonenzymatic glucose detection and also introduce an approach for the development of high-performance electrochemical sensors.