This research uses density functional theory approach combined with the spin–orbit coupling to study how the SOx molecules stick to Au5 cluster functionalized MoTe2 nanosheets. In fact, the promising Au/MoTe2 heterostructure system is constructed to model the attachment of gases on its surface. The high efficiency of adsorption process is evident from the strong sticking of the SOx to the Au atoms. Both Au1 and Au5 cluster modified MoTe2 nanosheets revealed semiconducting feature, and in Au5 cluster modified system, the band gap narrowed, while the conductivity is enhanced. Thus, results showed that adding Au cluster to the MoTe2 made it best for adsorbing gases, while MoTe2 without any additives absorbed the gases weakly. The conductivity and recovery time are also analyzed to further describe the results. Based on our theoretical consequences, the Au5 cluster functionalized MoTe2 (Au/MoTe2 heterostructure system) seem good for constructing innovative sensors to detect SOx molecules.