A novel nitrogen dioxide gas sensor based on TiO2-supported Au nanoparticles: a van der Waals corrected DFT study

Abstract

The interactions of nitrogen dioxide molecule with TiO 2 -supported Au nanoparticles were investigated using density functional theory. Surface Au atoms on the TiO 2 -supported Au overlayer were found to be the most favorable binding sites, thus making the adsorption process very strong. Both oxygen and nitrogen atoms of the NO 2 molecule can bind to the Au surface by forming strong chemical bonds. The adsorption of NO 2 molecule on the considered structures gives rise to significant changes in the bond lengths, bond angles, and adsorption energies of the complex systems. The results indicate that NO 2 adsorption on the TiO 2 -supported Au nanoparticle by its oxygen atoms is energetically more favorable than the NO 2 adsorption by its nitrogen atom, indicating the strong binding of NO 2 to the TiO 2 -supported Au through its oxygen atoms. Thus, the bridge configuration of TiO 2 / Au ? NO 2 is found to be the most stable configuration. Both oxygen and nitrogen atoms of NO 2 move favorably towards the Au surface, as confirmed by significant overlaps in the PDOSs of the atoms that forming chemical bonds. This study not only suggests a theoretical basis for gas-sensing properties of the TiO 2 -supported Au nanoparticles, but also offers a rational approach to develop nanostructure-based chemical sensors with improved performance.

First-principles calculations of adsorption sensitivity of Au-doped MoS2 gas sensor to main characteristic gases in oil

“…All theoretical calculations in this paper are based on the density functional theory (DFT) in Materials Studio (MS) [32,33]. The model construction, optimization and parameter calculation were completed by the DMol 3 module [34].…”

The Effect of Au Nanoparticle Addition on Humidity Sensing with Ultra-Small TiO2 Nanoparticles

“…Moreover, the effect of the addition of Au nanoparticles (5 nm) is investigated, which are selected to improve the water adsorption and to obtain improved transient response in terms of response and recovery times. The addition of Au nanoparticle allows the formation of Au/TiO 2 interfaces, which were proven to enhance water adsorption activity [16][17][18] and to act as favorable binding sites for different gases, providing faster response and recovery times [19][20][21][22]. It should be noted that the activation barrier for the dissociation of H 2 O at the Au-TiO 2 interface is substantially smaller than on the supported gold nanoparticle (0.6 eV vs. 1.3 eV) [17].…”

Use of nanostructured and modified TiO2 as a gas sensing agent

“…Incorporating Au into the TiO 2 surface is an example of chemical sensitization, as Au favors the connection between the molecules of the target gases and the metallic network. Abbasi and Sardroodi [105] made Au/TiO 2 sensors for the detection of NO 2 , where they revealed that the atoms that make up the target gas chemically bond to Au. This agrees well with Chomkitichai et al [106], who concluded that the H 2 gas detection performance increased with the introduction of 0 to 0.75% Au in TiO 2 .…”