Pd-doped h-BN monolayer: a promising gas scavenger for SF6 insulation devices

2020

ACS Omega

ZnO monolayers with desirable n-type semiconducting properties are full of potential for sensing applications. In this work, we investigate using first-principles theory the adsorption and sensing behaviors of Pd-doped ZnO (Pd-ZnO) monolayers with two typical dissolved gases, namely, H 2 and C 2 H 2 , to explore their sensing use for dissolved gas analysis in transformer oil. For Pd doping on the pristine ZnO monolayer, the T O site is identified as the most stable configuration with an E b of −1.44 eV. For the adsorption of H 2 and C 2 H 2 , chemisorption is determined given the large adsorption energy ( E ad ) and formation of new bonds. Analyses of the charge density difference and density of state provide evidence of the strong binding force of Pd–H and Pd–C bonds, while band structure analysis provides the sensing mechanism of the Pd-ZnO monolayer as a resistance-type sensor for H 2 and C 2 H 2 detection with high electrical responses. Also, analysis of the work function (WF) provides the possibility of selective detection of H 2 and C 2 H 2 using a Pd-ZnO monolayer-based field-effect transistor sensor given the opposite changing trend of the WF after their adsorption. Our work may broaden the application of ZnO-based gas sensors for application in the field of electrical engineering.

Section: Resultsmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 99%

First-Principles Insight into Pd-Doped ZnO Monolayers as a Promising Scavenger for Dissolved Gas Analysis in Transformer Oil

Zhou

2020

ACS Omega

“…1. This method is used to verify the energy band structure and density of states of the BN [29], which proves that this method is suitable for the calculation of the BN adsorption system.…”

Section: Computational Methods and Modelsmentioning

confidence: 90%

“…Through the energy analysis of the doping system, Graphene modified by the Rh atom appears to have a good adsorption effect on the H 2 molecule. Other researchers also found that Rh can perform more effectively than other doped transition metals [29][30][31]. Therefore, as a suitable metal, Rh adatom can enhance the surface properties of the 2D material monolayer.…”

Section: Introductionmentioning

confidence: 95%

Adsorption of NO, NO2 on Rh Embedded h-BN Monolayer: A First-Principles Study

Tian

et al. 2021

Preprint

Density functional theory calculations have been made to investigated the adsorption and sensing properties of harmful nitrogen oxides (NO, NO2) on rhodium (Rh) doped hexagonal boron nitride (BN) to explore the feasibility of Rh-doped BN (Rh-BN) based gas sensor. For each gas molecule, various adsorption positions and orientations were examined. The favorable adsorption configuration has been established and the corresponding adsorption energy has been calculated. Besides, to understand the adsorption mechanism, The properties such as electron density, the energy band structure, state density of states, and charge transfer of the adsorption system were investigated in greater detail. The calculations indicate that the most stable structure is that the Rh atom located directly above the N atom, and a stable chemical bond with a length of 2.096 Å formed between the Rh atom and N atom, with a significant binding energy (𝐸𝑏) of -1.561 eV. Then, adsorption performance of Rh-BN monolayer upon nitrogen oxides is in order as NO2 > NO, with the adsorption energy (𝐸𝑎) of -3.919 eV and -3.318 eV, respectively. This indicates that the Rh-BN single layer possesses ideal adsorption and sensing properties. Furthermore, by doping the Rh atom, many levels of impurities are introduced into the intrinsic BN band structure, thereby improving the interaction between BN and adsorbed gas molecules. Following adsorption of NO and NO2, the band gap (Eg) of the doping system is wider. It has been demonstrated that gas adsorption reduces the electrical conductivity of the system, but increases the sensitivity of the system. The above calculation and analysis are of great importance for the exploration of the Rh-BN single layer as innovative gas detection material.

“…The red and blue regions in the figure represent electron accumulation and depletion, respectively [ 22 ]. The electrons are mainly concentrated around the Ir atom, which illustrates that the bonds formed by Ir atom and surrounding S atoms have a strong binding force [ 30 ]. The Ir atom acts as an electron acceptor and obtains 0.274 e from MoS 2 monolayer, and the S mainly behaves as an electron donator.…”

Section: Resultsmentioning

confidence: 99%

The Adsorption and Sensing Performances of Ir-modified MoS2 Monolayer toward SF6 Decomposition Products: A DFT Study

Liu

Wang

et al. 2021

Nanomaterials

In this paper, the Ir-modified MoS2 monolayer is suggested as a novel gas sensor alternative for detecting the characteristic decomposition products of SF6, including H2S, SO2, and SOF2. The corresponding adsorption properties and sensing behaviors were systematically studied using the density functional theory (DFT) method. The theoretical calculation indicates that Ir modification can enhance the surface activity and improve the conductivity of the intrinsic MoS2. The physical structure formation, the density of states (DOS), deformation charge density (DCD), molecular orbital theory analysis, and work function (WF) were used to reveal the gas adsorption and sensing mechanism. These analyses demonstrated that the Ir-modified MoS2 monolayer used as sensing material displays high sensitivity to the target gases, especially for H2S gas. The gas sensitivity order and the recovery time of the sensing material to decomposition products were reasonably predicted. This contribution indicates the theoretical possibility of developing Ir-modified MoS2 as a gas sensor to detect characteristic decomposition gases of SF6.