A novel MoS2/Pd5 nanocluster heterojunction system with improved surface reactivity for efficient gas sensing: A DFT study

Abstract

Our work has reflected considerable interest in unique Pd nanocluster/MoS₂ heterojunction systems due to their potential applications in materials science, chemistry and physics. We focused on exploiting Pd₅/MoS₂ nanocluster system, a novel heterojunction material for gas sensing applications. In addition, we exploited the electronic properties of Pd dopant on the MoS₂ surface to make a comparative study. Our DFT calculations indicate that the Pd₅/MoS₂ heterojunction structure exhibits a higher affinity for adsorbing gas molecules such as CO, NH₃, NO, and NO₂, while the perfect MoS₂ shows weak gas adsorption capacity. Pd₅/MoS₂ heterojunction exhibits semiconducting feature with a weakened and narrower band gap, making it more suitable for gas sensing due to its higher conductivity. We analyzed important factors like adsorption distance/energies, density of states, band structure and difference of electron density concerning adsorbed gases on the heterojunction surface. Based on the electron density difference maps, we can see the giant growth of charges over the adsorbed molecules, as well as between the adsorbing atoms. Based on our findings, the conductivity of the nanomaterial undergoes a remarkable change, which helps reinforce the applicability of the Pd₅/MoS₂ heterojunction nanosystem in sensing and adsorbing gas molecules.