Improvement of The CO2 Sensitivity of HPTS Along With ZnO/CuO Nanoparticles: A Comparative Study Between Core-Shell And Hybrid Structures

Abstract

Semiconductor metal oxide materials have gained huge attention in gas sensors owing to their high sensitivity to many target gases. Herein, ZnO/CuO core-shell and ZnO/CuO hybrid, which were synthesized by different sol-gel methods and formed in two different crystal structures, were used as an additive material to enhance the response range of 8-hydroxypyrene-1, 3, 6-trisulfonic acid (HPTS) for the sensing of gaseous carbon dioxide. Metal oxide materials were characterized by using XPS, XRD, FTIR, SEM, UV-Vis, and PL spectroscopy. The HPTS dye along with the ZnO/CuO hybrid material displayed a higher CO2 gas sensitivity as 94% ratio (I0/I100=16.90) and Stern-Volmer constant (KSV) value and extended linear response range compared to the HPTS-based sensing thin films along with ZnO/CuO coreshell material and additive-free form. ZnO/CuO core-shell and hybrid structures were used for enhancing of carbon dioxide sensitivity of the HPTS dye.

Improvement of the CO2 Sensitivity: HPTS-Based Sensors along with Zn@SnO2 and Sn@ZnO Additives

“…Techniques based on infrared absorptiometry, electrochemistry, and luminescence can be used to primarily identify the presence of CO 2 gas. Optical sensors have gained popularity in recent years as a result of their advantages, such as electrical isolation, minimal noise interference, lower cost, fast response, adaptability for miniaturization, and simplicity of production and use. − Currently, electrochemical and optical devices based on spectroscopic changes are used to measure CO 2 , but optical chemical measurement methods have advantages, such as shorter response times, greater sensitivity, stability, and lower prices. The most common pH-sensitive fluorescent indicator dye, 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS), is commonly used for the accurate and continuous monitoring of dissolved CO 2 gas in various research fields.…”

“…Despite the widespread use of HPTS dye in optical applications and its superior response to CO 2 , it exhibits some disadvantages, such as stability, low relative signal variation, and reproducibility. As such, HPTS dye has been used with various additives such as ionic liquids (ILs), metal oxide nanoparticles (NPs), , coordination polymers (CPs), and/or metal oxide semiconductors (MOSs) , to eliminate such disadvantages. By incorporating MOSs into the sensor design, it is possible to increase the sensitivity and selectivity toward gas molecules.…”