A method for integrating ZnO coated nanosprings into a low cost redox-based chemical sensor and catalytic tool for determining gas phase reaction kinetics

Abstract

A chemical sensor (chemiresistor) was constructed from a xenon light bulb by coating it with a 3-D zinc oxide coated silica nanospring mat, where the xenon light bulb serves as the sensor heater. The sensor response to toluene as a function of xenon light bulb sensor temperature (TLB) and vapor temperature (TV) was observed and analyzed. The optimum operational parameters in terms of TLB and TV were determined to be 435 °C and 250 °C, respectively. The activation energy of toluene oxidation (Ed) on the ZnO surface was determined to be 87 kJ·mol-1, while the activation energy of oxidation (Ea) of the depleted ZnO surface was determined to be 83 kJ·mol-1. This study serves as proof of principle for integrating nanomaterials into an inexpensive sensor platform, which can also be used to characterize gas-solid, or vapor-solid, redox processes.