Influences of Work Function Changes in NO2 and H2S Adsorption on Pd-Doped ZnGa2O4(111) Thin Films: First-Principles Studies

Jen-Chuan Tung,Yu-Hsuan Chen,Po-Liang Liu,Ding-Yuan Wang

doi:10.3390/app11115259

Jen-Chuan Tung, Yu-Hsuan Chen + Show 2 more

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https://doi.org/10.3390/app11115259

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Abstract

The work function variations of NO2 and H2S molecules on Pd-adsorbed ZnGa2O4(111) were calculated using first-principle calculations. For the bonding of a nitrogen atom from a single NO2 molecule to a Pd atom, the maximum work function change was +1.37 eV, and for the bonding of two NO2 molecules to a Pd atom, the maximum work function change was +2.37 eV. For H2S adsorption, the maximum work function change was reduced from −0.90 eV to −1.82 eV for bonding sulfur atoms from a single and two H2S molecules to a Pd atom, respectively. Thus, for both NO2 and H2S, the work function change increased with an increase in gas concentration, showing that Pd-decorated ZnGa2O4(111) is a suitable material in NO2/H2S gas detectors.

Highlights

Gas sensors for household and industrial usages have attracted much attention since1970 [1]
Using the framework of density functional theory, we studied the adsorption reactions and work functions of NO2 and hydrogen sulfide (H2 S) on Pd-ZnGa2 O4 (111) surfaces
We found that the work function change of one NO2 (H2 S) molecule on the Pd-ZGO(111) surface is enhanced to

Summary

Introduction

Gas sensors for household and industrial usages have attracted much attention since. 1970 [1]. Metal oxide semiconductors [4], such as SnO2 , Ga2 O3 , and WO3, have been widely studied and used as gas sensors [5–11]. The gas adsorption reaction is converted into the sensitivity response of the sensor to detect gas by measuring the work function, capacitance, conductivity [10,12–15], optical characteristics, and other parameters of the sensing material surface. The density functional theory (DFT) has been widely used in the fields of the gas-sensing mechanism, adsorption of atoms and molecules on surfaces, and surface reconstruction [6,7]. The sensitivity response of the to sensor detect the target gas can molecules. The sensitivity response of the sensor detecttothe target gas can be be determined by the following work function changes. We hope that this work can help experimental researchers to effectively develop gas-sensing devices.

Computational Details

Structures

Work Functions

Adsorption Energies

Conclusions