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

• Pd5 cluster decoration in the MoS2 is energetically favorable for gas adsorption. • Pd-doped and Pd5 decorated MoS2 monolayers fall within the scope of semiconductor materials. • The adsorption of gas molecules are stronger on the Pd5/MoS2 heterojunction than that on pure MoS2. Our work has reflected considerable interest in unique Pd nanocluster/MoS 2 heterojunction systems due to their potential applications in materials science, chemistry and physics. We focused on exploiting Pd 5 /MoS 2 nanocluster system, a novel heterojunction material for gas sensing applications. In addition, we exploited the electronic properties of Pd dopant on the MoS 2 surface to make a comparative study. Our DFT calculations indicate that the Pd 5 /MoS 2 heterojunction structure exhibits a higher affinity for adsorbing gas molecules such as CO, NH 3 , NO, and NO 2 , while the perfect MoS 2 shows weak gas adsorption capacity. Pd 5 /MoS 2 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 Pd 5 /MoS 2 heterojunction nanosystem in sensing and adsorbing gas molecules.