Molecular Adsorption of NH3 and NO2 on Zr and Hf Dichalcogenides (S, Se, Te) Monolayers: A Density Functional Theory Study

Abstract

Due to their atomic thicknesses and semiconducting properties, two-dimensional transition metal dichalcogenides (TMDCs) are gaining increasing research interest. Among them, Hf- and Zr-based TMDCs demonstrate the unique advantage that their oxides (HfO2 and ZrO2) are excellent dielectric materials. One possible method to precisely tune the material properties of two-dimensional atomically thin nanomaterials is to adsorb molecules on their surfaces as non-bonded dopants. In the present work, the molecular adsorption of NO2 and NH3 on the two-dimensional trigonal prismatic (1H) and octahedral (1T) phases of Hf and Zr dichalcogenides (S, Se, Te) is studied using dispersion-corrected periodic density functional theory (DFT) calculations. The adsorption configuration, energy, and charge-transfer properties during molecular adsorption are investigated. In addition, the effects of the molecular dopants (NH3 and NO2) on the electronic structure of the materials are studied. It was observed that the adsorbed NH3 donates electrons to the conduction band of the Hf (Zr) dichalcogenides, while NO2 receives electrons from the valance band. Furthermore, the NO2 dopant affects than NH3 significantly. The resulting band structure of the molecularly doped Zr and Hf dichalcogenides are modulated by the molecular adsorbates. This study explores, not only the properties of the two-dimensional 1H and 1T phases of Hf and Zr dichalcogenides (S, Se, Te), but also tunes their electronic properties by adsorbing non-bonded dopants.

Atomic insights into the interaction of N2, CO2, NH3, NO, and NO2 gas molecules with Zn2(V, Nb, Ta)N3 ternary nitride monolayers

“…NH 3 is a donor to the Zn 2 TaN 3 monolayer, as for most of 2D materials, but it is hardly removable (t = 1.56 Â 10 7 s) from its surface, which is different from most of 2D materials, where NH 3 possesses a weak van der Waals interaction. [96][97][98][99] NO and NO 2 induce local dipoles of a different orientation on the Zn 2 TaN 3 monolayer surface, which can facilitate their detection. 100,101…”

Adsorption and Gas-Sensing Performance of the Small-Molecule Gas on ZrSe2 Monolayers: A First-Principles Study

“…Transition-metal dihalogenate (TMD) layered materials have not only excellent physical and chemical properties but also band gaps that graphene lacks, which has led to their increased use in gas sensors. − For example, Liu et al used density functional theory (DFT) to investigate the gas-sensitive properties of Ir-modified MoS 2 monolayer films to three typical gases in transformer oil: methane (CH 4 ), ethane (C 2 H 4 ), and acetylene (C 2 H 2 ). Based on the analysis of state density (DOS) and charge density difference (CDD), it is shown that Ir decorated MoS 2 has a great prospect as a gas sensor for dissolved gas detection .…”

Sulfur-Rich N-Doped Co9S8 Catalyst for Highly Efficient and Durable Overall Water Electrolysis Application

“…For example, due to its high conductivity, intrinsic kinematics, robustness, mixed valence state, and efficient and durable electrochemical activity, Co 9 S 8 is considered a promising electrocatalyst material [13][14][15], but it suffers from poor electrochemical activity arising from its sluggish kinetics during catalytic OER and HER processes [18][19][20]. The catalytic activity of an electrocatalyst is mainly determined by its electronic structure, which can be altered intrinsically via the addition of heteroatoms (e.g., N and S) to the host structure [21,22]. The unfilled outermost 2p and 3p respective orbitals of N and S exhibit promising electron-withdrawing ability and high electronegativity due to the capture of electrons from adjacent Co atoms via acceptor/donor interactions [17,21,23].…”