Highly dispersed Pt nanoparticles onto dendritic silica as colorimetric probe for CO sensing in mainstream cigarette smokes

Abstract

Carbon monoxide (CO) is a typical substance harmful to human body produced during cigarette smoking. Its content in cigarette smoke is one of the important indicators for evaluating its toxicity and the filtration effect of cigarette filter tips, which provides important guidance for its rational design. In this work, Pt nanoparticles with superior peroxidase catalytic ability were synthesized and loaded onto fibrous SiO2 nanoparticles as nanozymes to detect CO in cigarette smoke by taking advantage of the reduced catalytic performance of CO adsorption on the active sites of the nanozymes. The fibrous SiO2 not only provide abundant sites for the deposition and dispersion of Pt NPs, but also prevent their aggregation and thus maintain their high catalytic activity. Density functional theory calculations reveal that Pt nanoparticles exhibits superior peroxidase ability over Au and Pd nanoparticles, which can be significantly inhibited by CO. Accordingly, a nanozyme-inhibition based colorimetric method was developed for the detection of CO in cigarette smoke with the limit of detection of 0.15 mg/L. The applicability of this method was validated by analyzing the CO contents in 8 kinds of cigarette smoke with different types of filter tips. The concentrations of CO are in the range of 5.40–6.73 mg/branch, which are in good agreement with those of GC results, indicating the accuracy and reliability of our method. This assay is fast, convenient and sensitive for quantitatively assessing the CO content in cigarette smoke, and it lays the foundation for prompting the widespread use of nanozyme-inhibition in chemical sensing.