Bimetallic decoration is a promising technique for enhancing the gas-sensing characteristics of resistive sensors. In this study, pristine WS₂ nanosheets (NSs), Ru-implanted WS₂ NSs, separate Pt and Pd nanoparticles (NPs) decorated on Ru-implanted WS₂ NSs, and Pt/Pd bimetallic NPs decorated on Ru-implanted WS₂ NSs sensors were prepared and utilized for acetone detection in self-heating operations at low applied voltages (1–5 V). The gas sensors were characterized by employing various techniques to explore their phases, morphologies, and chemical compositions. The Ru-implanted WS₂ NSs sensor decorated with Pt/Pd bimetallic NPs exhibited good selectivity and fast dynamics toward acetone. Also, the optimized sensor displayed an acceptable response to acetone even in a high-humidity environment. The enhanced acetone sensing of the optimized gas sensor was related to the spillover and catalytic effects of the implanted Ru and Pt/Pd NPs on acetone, enhanced oxygen ionosorption with the formation of defects under implantation, and the formation of Schottky barriers between Pt/Pd and Ru-implanted WS₂. We successfully demonstrated the potential of this novel sensing material for room-temperature acetone sensing.