Spatially Binary Single-Atom La and Mn Sites on Co 3 O 4 for Enhanced Triethylamine Sensing

Triethylamine (TEA) is a hazardous volatile organic compound, and its sensitive and selective detection remains challenging due to the constraints of isolated strategies for improving gas-sensing properties. Herein, we report hollow Co 3 O 4 nanotubes with spatially binary single-atom Mn 3+ and La 3+ sites, which synergistically modulate the electronic structure and defect density to enhance TEA sensing. STEM imaging revealed the spatially binary single-atom Mn 3+ and La 3+ sites on Co 3 O 4 nanotubes. Aberration-corrected STEM confirms Mn 3+ substitutional doping within the lattice and atomically La 3+ anchoring at the surface. With a Co 2+ /Co 3+ ratio of 0.95 and a 2.2-fold rise in oxygen-vacancy density (31.0%), spatially distributed La&Mn-Co 3 O 4 couples Mn-driven electronic activation with La-mediated chemisorption to achieve a 3.4-fold higher response to 100 ppm TEA and a 20 °C lower operating temperature than pristine Co 3 O 4, along with a 1.5-fold improvement in selectivity index. Density functional theory with the Hubbard U correction (DFT + U ) simulation indicates that Mn 3+ introduces mid-gap states and enhances O 2p spin polarization, whereas surface La 3+ provides Lewis acidic binding sites to stabilize TEA adsorption and synergistically downshift the O 2p antibonding band. The combined effects strengthen TEA adsorption and improve sensor performance. This work demonstrates a viable single‐atom dual-dopant approach to design high‐sensitivity and selective gas sensors, offering insights into the atomic‐scale tuning of semiconductor surfaces for chemical sensing applications.