First-Principles Study of Gas Molecule Adsorption on C-doped Zigzag Phosphorene Nanoribbons

DFT Study on the Janus ZrSSe Monolayer for Its Potential Application in NO Gas Sensing

The growth of industry has resulted in increased global air pollution, necessitating the urgent development of highly sensitive gas detectors. In this work, the adsorption of the Janus ZrSSe monolayer for CO, CO2, NH3, NO, NO2, and O2 was studied by first-principles calculations. First, the stability of the ZrSSe monolayer is confirmed through calculations of cohesive energy and AIMD simulations. Furthermore, the calculations indicate that the Se layer exhibits higher selectivity and sensitivity toward gas molecules compared to the S layer. Specifically, among the gases adsorbed on the Se layer, NO has the shortest adsorption distance (1.804 Å), the lowest adsorption energy (-0.424 eV), and the greatest electron transfer (0.098 e). Additionally, density of states analysis reveals that adsorption of NO, NO2, and O2 on the Janus ZrSSe monolayer can induce a transition from a nonmagnetic to a magnetic state. The adsorption of NO not only alters the magnetic state but also induces a transition from a semiconductor to metal, which is highly advantageous for gas sensing applications. There results suggest that the Janus ZrSSe monolayer has the potential to serve as a highly sensitive detector for NO gas.

High-Throughput Screening of Atomic Defects in MXenes for CO2 Capture, Activation, and Dissociation

The capture, activation, and dissociation of carbon dioxide (CO₂) is of fundamental interest to overcome the ramifications of the greenhouse effect. In this regard, high-throughput screening of two-dimensional MXenes has been examined using well-resolved first-principles simulations through DFT-D3 dispersion correction. We systematically investigated different types of structural defects to understand their influence on the performance of M₂X-type MXenes. Defect calculations demonstrate that the formation of M₂C(V_MC) and M₂N(V_MN) vacancies require higher energy, while M₂C(V_C) and M₂N(V_N) vacancies are favorable to form during the synthesis of M₂X-type MXenes. The M₂X-type MXenes from group III to VII series show remarkable behavior for active capturing of CO₂, especially group IV (Ti₂X and Zr₂X) MXenes exhibit unprecedentedly high adsorption energies and charge transfer (>2e) from M₂X to CO₂. The potential CO₂ capture, activation, and dissociation abilities of MXenes are emanated from Dewar interactions involving hybridization between π orbitals of CO₂ and metal d-orbitals. Our high-throughput screening demonstrates chemisorption of CO₂ on pure and defective MXenes, followed by dissociation into CO and O species.

Zipper phosphorene as sensing element towards formaldehyde and acetaldehyde - A first-principles insight

We ascertained the structural stability of zipper phosphorene nanosheet (zP-NS) and studied the adsorption behaviour of toxic aldehyde compounds including formaldehyde (FD) and acetaldehyde (AD) on zP-NS based on first-principles calculation. Considerably, zP-NS reveal a semiconducting character with band gap of 1.35 eV. Especially, four distinct favourable adsorption positions including bridge-, hollow-, top- and valley-site of FD and AD vapours on zP-NS were investigated. Furthermore, the calculated binding-energy of prominent adsorption sites are observed to be in the scope of -0.143 eV to -0.411 eV advocating physisorption nature of the interaction of chief aldehydes on zP-NS. The overall outcomes recommend that zP-NS can be persuasively utilised as a chemical sensor for monitoring FD and AD molecules in indoor air environment.

Impact of structure, doping and defect-engineering in 2D materials on CO2 capture and conversion

2D material based strategies for adsorption and conversion of CO2 to value-added products.