Enhanced capture and electronic sensing of catechol by transition metal-decorated silicon carbide monolayers: First-principles insights

The efficient detection and removal of catechol are critical for environmental monitoring due to its high toxicity. In this study, first-principles calculations based on Density Functional Theory (DFT) were performed to investigate the sensing and capture capabilities of two-dimensional silicon carbide (2D-SiC) monolayers functionalized with transition metal (TM) adatoms (Ag, Au, Pd, Ti). Our results demonstrate that TM decoration significantly enhances surface reactivity compared to the pristine 2D-SiC. The Ti-decorated platform exhibits the strongest interaction, with an adsorption energy of 2.41 eV and a significant charge transfer of 0.369 | e |, driven by a robust sp 2 -to-sp 3 hybridization transition and localized structural buckling. Electronic analysis reveals that catechol adsorption induces notable modulations in the bandgap and work function of the decorated layers. Specifically, Au- and Pd-decorated monolayers show significant bandgap variations (∼0.4 eV), acting through "turn-on" and "turn-off" chemiresistive mechanisms, respectively. Conversely, the electronic stability of the Ti-decorated system, combined with its high binding affinity, positions it as an ideal candidate for environmental remediation and capture rather than reversible sensing. These findings provide a theoretical framework for the development of high-performance 2D-SiC-based devices for targeted environmental applications.