Paracetamol-Assisted Self-Assembled ZnO Porous Microstructures for Enhanced CO2 Detection

Abstract

Paracetamol-assisted zinc oxide (ZnO) highly porous micro-flakes were synthesized by a rapid two-step synthesis: precipitation (with sodium hydroxide) and calcination (at 250°C for 1 h). Addition of paracetamol during the synthesis not only inhibited the growth of ZnO grains but also originated self-assembly of the micro-flakes resulting in highly porous flower like structures. Increase in paracetamol concentration also increased porosity on ZnO microstructures due to the self-assembly of thinner flakes without any structural changes. X-ray diffraction (XRD) shows the preferential orientation of powders in the (101) direction of hexagonal structure. Raman spectra is dominated by E2 (high) optical mode due to vibration of oxygen atoms. Samples were tested for gas detection at 50, 100, 200, 400, 800 and 1000 (parts per million) PPM concentration of carbon dioxide (CO2). ZnO porous microstructures were obtained with a high concentration of paracetamol, enhancing the carbon dioxide sensing response from 20% to 90% with a response time of 60 s. These simple, low-cost and highly porous self-assembled ZnO structures with enhanced CO2 detection will be of interest for several researchers in the chemical sensor fabrication field.