Computational Study on Enhanced CO Sensing Properties of Boron-doped Zn12O12 Nanocluster

Abstract

CO is a threat to human life and environment. It causes CO poisoning and atmospheric pollution causing global warming. Recently detection and sensing of CO has become a huge challenge because of colorless and odorless nature of CO. For the environment protection from the CO toxicity, different devices have been identified for its detection and capturing. Metal oxide e.g. Zn12O12, WO3, TiO2 are semiconductors and are used as sensing materials for gases like CO2, CO, H2 etc. Nanostructured Zn12O12 is a metal oxide semiconductor. It rationalizes the resistance behavior upon CO adsorption. Doping manipulates the geometry of nanocluster making it highly sensitive to CO gas based on change in conductivity due to presence of CO molecules. Our work focuses on the importance of boron-doped nanostructured Zn12O12 signaling CO hence reducing the critical risk factors related to CO gas. Moreover, public and medical awareness regarding hazards of CO gas toxicity can be provided by designing CO gas sensors. Herein; we investigated that boron-doped nanostructured Zn12O12 sensors are efficient to CO sensing as compared to pristine, dealing with its electronic, thermodynamic and spectroscopic properties. Electronic (EHOMO, ELUMO, Eg, DOS, QT) and thermodynamic (ΔG, ΔH, S) parameters were calculated to measure doped Zn12O12 nanocluster sensing potential for CO. Introduction of dopant (boron) in Zn12O12 nanocluster, reduced the HOMO-LUMO gap i.e. 1.04 eV, and resistance hence enhancing the adsorption energy (i.e. 4.9), the stability and the electrical conductivity of nanocluster towards CO. The increasing entropy and negative value of ΔH and ΔG indicated that adsorption of CO over boron-doped Zn12O12 NC is energetically more favorable. UV/Vis spectroscopic analysis revealed that the doping of boron resulted in the shifting of spectral range to fluorescent region depicting radiation emission by boron-doped Zn12O12 upon CO sensing and capturing. Concentration of CO gas molecules were increased and investigated the sensing behavior of boron-doped Zn12O12 nanocluster which showed that singly doped Zn12O12 NC can sense up to 5 CO molecules.