Surface Defect-Induced Specific Catalysis Activates 100% Selective Sensing toward Amine Gases at Room Temperature.

Abstract

Achieving selective sensing toward target volatile organic compound gases is of vital importance in the fields of air quality assessment, food freshness evaluation, and diagnosis of patients via exhaled breath. However, chemiresistive sensors that exhibit specificity like biological enzymes in a complex environment are rare. Herein, we developed a strategy of optimizing oxygen vacancy structures in tin oxides to induce specific catalysis, activating 100% selective sensing toward amine gases at room temperature. <i>In situ</i> technologies and theoretical calculations reveal that the "donor-receptor" coordination between nitrogen atoms from amine molecules and bridging oxygen vacancies (OV_Bri)-induced electron-deficient center is the essence of specific catalysis and provides the bridge from the surface oxidation reaction to electrophysical characteristics evolution, which allows the sensor to exhibit amine-specific sensing behavior, even in gas mixtures. Moreover, OV_Bri enhances the selectivity by enabling a room-temperature sensing pathway where lattice oxygens participate in catalytic oxidation for amine molecules, resulting in record-high sensing values: 19,938.92 toward 100 ppm of triethylamine, 15,236.78 toward trimethylamine, and 123.41 toward diethylamine. Our findings illustrate the feasibility of designing specific active sites through defect engineering and can contribute to the advancement of highly selective sensors based on catalytic processes.