First-Principles Investigation of Glucose Adsorption and Sensing-Related Electronic Modulation on Ti₃C₂O₂ MXene

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Two-dimensional Ti₃C₂O₂ MXene is a promising material for non-enzymatic glucose sensing due to its conductivity and biocompatibility.
• The precise atomic-scale sensing mechanism of glucose on MXene surfaces is not fully understood.

Purpose of the Study:

• To elucidate the atomic-scale interactions between glucose and Ti₃C₂O₂ MXene using density functional theory (DFT).
• To investigate the sensing mechanism and potential selectivity against common interferents.

Main Methods:

• Density Functional Theory (DFT) calculations employing the PBE functional with D3(BJ) dispersion correction.
• Simulation of glucose adsorption on pristine Ti₃C₂O₂ MXene under idealized vacuum conditions.
• Analysis of adsorption energy, charge transfer (Bader analysis), and density of states (DOS) changes.

Main Results:

• β-d-glucose adsorbs onto Ti₃C₂O₂ MXene with a strong adsorption energy (-0.82 eV) via hydrogen bonding.
• Electron transfer from MXene to glucose (0.15 electrons) leads to a Fermi level shift and reduced DOS at the Fermi level, indicating sensing potential.
• Calculated sensitivity and detection limit are consistent with experimental MXene-based glucose sensors; glucose shows stronger binding than lactate and urea.

Conclusions:

• The study provides baseline mechanistic insights into glucose-MXene interactions, supporting the rational design of MXene-based glucose sensors.
• DFT calculations reveal glucose's preferential binding and electronic perturbations on MXene, crucial for sensor performance.
• Acknowledged limitations include idealized conditions (vacuum, pure termination, zero Kelvin) that necessitate further experimental validation.